My Cherokee has been driving me nuts. It's been overheating since we replaced the water pump that was leaking bad enough to cause an over-temperature situation. The radiator did have some clogging but that was resolved with a new all metal 2 row radiator. Basically everything new in the cooling system except the rad cap and that tested out okay. Still it would over heat when worked mildly, as in steeper than usual stretches of upgrade.
The oil was fine; looked like oil, not a milkshake. Coolant looked fine. When it overheated it would puke two or three quarts. Then sitting on the driveway running the engine, A/C on to create load, electric fan disconnected in an effort to see what's going on, I discovered bubbling, boiling in the coolant expansion / overflow bottle. Going like a percolator.
Some Jeeps have a head that gives trouble. All is usually fine until one has an over heating event. Then many of these heads develop small cracks. Sometimes that causes water in the oil and vice versa. sometimes it does not. Sometimes it percolates like mine did.
So I have a reman head, almost completed the install. I lost a socket someplace in the garage (I suppose) or someplace. I can not find it! Had to get a new one. It seems most auto parts stores don't carry it. Due to head bolt design it must be a 12 point socket, 13 MM. The only place around here that has that in stock is NAPA. I know because when I was tearing it down I ran into the issue and had to buy one. I bought the only one the local store had yesterday. Then I lost it. So they are bringing one over from the warehouse in ABQ. I'll have it this afternoon. Perhaps SnapOn has them too, maybe Matco, but I didn't try to chase them down.
It's maddening though because you need a deep socket as half the bolts have a threaded top stud portion. OK, that's what I bought. it's a 3/8" drive. I wanted a 1/2" but all they carried was this deep 13 MM 3/8" drive. I can use andapter so it's no problem, right? Wrong. The rear most stud on the drivers side is close to the bodywork. Try as I might there was no way to get a deep socket plus an adapter and the wrench in there. OK, no real problem, just use a 3/8" handle, right? Well half right. That's fine for disassembly. (Oh this stud is one of the ones with a stud extension on top, so a deep socket is a must.)
For assembly a torque wrench is required. Have to hit 110 ft lbs. My 3/8" drive torque wrench stops at 75 ft lbs. Everybody around here has 3/8 drives that measure inch lbs. Well NAPA has some nice 3/8" drive torque wrenches but they are $180 and up. Still cheaper than having a shop do the head, but I have no other use for it. Ah, NAPA has a 13 MM standard length socket in 1/2" drive; that would fit my torque wrench. That's cool! Oh, but wait, the std length socket won't be usable on that head bolt (with the threaded stud top). .... This is one of the few such head bolts that actually makes use of the upper threads. The engine ground strap attaches to it.
After reflection, I cut enough off the top of that bolt. Just enough to enable use of a std length socket. Then I found some thin nuts to use for securing the ground starp and the bracket that secures a wiring harness.
More than likely none of the Cherokee owners here will ever be changing their head with the engine in the vehicle. But be warned, you need the correct 13MM 12 point socket(s) to do the job. I have never seen this issue on any of the Jeep forums but I only go there once in a while so may have missed, not found it.
Anyhow the new socket should be here in an hour or so. I just had to vent a little.
You have my sympathy Don!
I never had to change the head on my Cherokee but I did on my wagoneer >:( I made a lot of tools.
If you really want something to make you cuss, buy your wife a Land Rover. You have to pull the manifold to change the spark plug wires and that's one of the simple maintenance items.
The optimist in me is glad it cracked in a good spot! Had it leaked into the oil, you could have been looking at bottom end damage! (Of course, had that happened, you would have had an excuse to put a 4.2 crank in ;D )
As annoying as it can be to work on the I-6s, especially near the firewall, they sure do go the distance. My 98 cherokee just rolled over 200k on Tuesday.
Quote from: mgramann on July 26, 2012, 04:51:16 PM
The optimist in me is glad it cracked in a good spot!
:) and the sockets were on sale too!
"You have to pull the manifold to change the spark plug wires and that's one of the simple maintenance items"
arr you'l be talking about the Disco 2 spark packs ! cunningly situated between the engine and the bulkhead
remove secondary air tube- dislocate three fingers and wrist and its easy !
well actually I lay on the engine on cardboard and used a bent pair of snipe nosed pliers !
But yes I was wondering why the F an engineer would ever put a standard maintenance item situated in such a ridiculus place ! hopefully TATA have fired him
hopefully you didnt loose the socket in the cylender
Quote from: CjAl on July 26, 2012, 08:37:54 PM
hopefully you didnt loose the socket in the cylinder
[rofl2] [rofl2] No, I checked there. ;D
I did find it on the floor where it had rolled up under the tire. Now I have a spare. :D
Head's on, manifolds are on, starting on rehanging the P/S, A/C, etc. etc. in the AM
I cracked a 360 similarly it sounds like. With the radiator cap off, romping the gas caused an exhaust powered geyser
i have a friend with a cherokee with a very similar problem right now. after new water pump, thermostats, cap and radiator its still running warm while driving but not idling.
i may have to be the bearer of bad news once again.
If the coolant and oil show no contamination there is a test that will reveal the presence of the products of combustion in the coolant. In my case I found I could induce bubbling/boiling by put a sheet of cardboard in front of the grill, disconnecting the electric fan, turning on the A/C and running the engine at 2500 RPM or so for a few minutes. The overflow tank would start bubbling/boiling.
I saw something on TV awhile back that may help. A spark plug modified with an air hose fitting can test this. It will also check the condition of the rings and valves. Each cylinder should be checked at TDC. Upon being pressurized, if the coolant bubbles, it's a head gasket or head issue. If air comes out of the crankcase oil fill, the cylinder rings are likely worn. If air comes out of the throttle body, intake valves aren't seating correctly. If air comes out of the exhaust, the exhaust valves are a problem.
Makes me glad that I just picked the parts out and had our shop do it for us. ;D
We *DO* have alot of the reverse TORX bits, but I don't recall having any deep socket ones.
The lives!!! Started right up. Test drive later.
I may grumble about the weird stuff I run into when doing mechanical work, but it beats paying the shop. Sort of funny, I did not begrudge them the cost of replacing the belt idler on the Honda... couple hundred bucks or so. But I was going to feel really bad if I forked over the cash for this job. It also helps that there was no time crunch to get it completed. ... I also replaced the fan shroud as it fractured into 4 pieces when I went to reinstall it. The plastic gets brittle after many hours of heat. The local dealer had one in stock so it must be fairly common.
i am done buying new vehicles. i sold my 2010 dodge ram and i am sticking to my early 90's vehicles except for the 04 wrangler. i can rebuild them almost indefinatly and do it all myself. thats gold in the age of $100+/hr shop rates.
a friend of mine works at toyota as a tech. do you know you have to disassemble the entire front end of a prius to change the headlights? ya, thats good engineering
Since I was 17 I think I only ever paid a mechanic once- for a BMW engine rebuild after a catostrophic head gasket failure at about 125 mph
He 'repaired' it, then it dropped a valve during the test drive....writing off another bunch of parts.
eventually got a second engine from france and swapped that in.
Still now when really I can afford to pay some one else I still tend to do things myself, it gets done right and I find tinkering enjoyable.
Things I wont touch are auto transmissions, and major engine repairs, even head gaskets these days on the V style engines can be a pain in the rear with so much electronics involved.
Loved working on my wrangler 6 cyl - simple robust engineering- good luck on the test later today !
motors are what i prefer to build. auto transmissions are not too bad they are just intimidating, lots of parts to keep track of. i have rebuilt two but admit that my 220k mi suburban makes me cringe every time the tranny does something out of the ordinary.
Quote from: CjAl on July 29, 2012, 08:14:32 AM
motors are what i prefer to build. auto transmissions are not too bad they are just intimidating, lots of parts to keep track of. i have rebuilt two but admit that my 220k mi suburban makes me cringe every time the tranny does something out of the ordinary.
You should have a 95 Bronco. They made that transmission just to give me ulcers.
... I'd of probably put a couple of 300 grain hollow point 45's into it by now!
It still overheats and bubbles/boiling occurs in the expansion/overflow tank, when working hard on an upgrade. *#&%@!!
Tomorrow I'm leaving it at Quanz (http://www.quanzautocare.com/) (one of the few places I have faith in) for their opinion and some testing. Then we're heading to the cabin for a few days in a borrowed F150 4x4. There's not much left to suspect and there's one I don't care to think about.
thats not good.
Hey Don---this reminds me of our old Dodge Coronet 500 3-on-the-tree war wagon me and my brothers all learned to drive in. It would idle fine but overheat with any demands put on it. We tried advancing the timing and putting more expensive gas in, in case it was pre-detonating-- Dad tried everything to increase the coolant flow to no avail----it wasn't until he put in a more restrictive thermostat that impeded flow a bit that made it run cool again.....The coolant wasn't spending enough time in the radiator.
Radiator cap been pressure tested, thermostat also makes sense.
That's weird.
Any chance the impellor on the water pump is slipping on the inside of the pump? What if you completely remove the thermostat? Hmmm... hopefully Quanz will figure it out. I usually don't use them because they seem to be a bit high priced. But I don't mind paying more if they get it right the first time.
you guys arent taking into account the pressurozed cooling system. that means compression from somewhere. if its not the gasket and not the head then it has to be the block. i have seen many small hairline cracks that were initially missed because they were so small but once it heated up it would expand. so hopefully they missed something in the head. bad head is bad but still better then a bad block
Crap Don that sucks! How many miles on the rig?
I solved my problem on my last trip by cleaning my K&N filter -- no joke! d*
But I still have some O2 sensor problems or a bad catalytic converter (PO171 code I beleive)....
I carry a code reader everywhere I go so I can check the 'check engine' light if it comes on and since I'm out of work will be doing my own mechanicing now to. First up will be replacing the rad and fan shroud and skid plate...then we'll see if she heats up under load.
Also I plan to replace the O2 sensors.
Anyway, again, I'm sorry to hear about the issues....can't imagine what might be the problem since you replaced everything! One thing to check though is the dizzy (distributor). Seems on older jeeps as they wear the dizzy can loosen up and cause timing issues. There is a mod that can be done to resolve this, or a new (er) on can be installed. If the dizzy causes the timing to advance a little too much, or to retard a little too much then it's possible to cause overheating -- so too can leanout caused by too much air and not enough fuel (clogged injectors or clogged fuel filter) -- might check those to.
BTW, the most likely socket in my collection to go run off with a measuring tape is 13mm too. Something about that size just has a wild hair.
I have my fingers crossed Don. There are still a few things that can cause it and hopefully they'll find it's one of them.
In any event, rebuilt short blocks aren't that expensive, just a lot of work.
http://www.steelseal.com/store/pc/viewcontent.asp?idpage=1
I had good luck with this on a head gasket leak, only a small one but held for over a year before we left the states all was working fine
LOL Our 13mm long socket always seems to go missing. Just about read to have it chained somewhere on the Jeep, JUST so it doesn't walk off again. That and a few Torx bits.
Hopefully she gets back up and running soon for ya
Quote from: NM_Shooter on August 03, 2012, 10:29:26 AM
BTW, the most likely socket in my collection to go run off with a measuring tape is 13mm too. Something about that size just has a wild hair.
as long as the 1/2" sticks around you'll be ok ;)
Oh and I HATE METRIC.....just sayin' lol d*
I'm really hoping it's an easy fix. As I mentioned earlier, even if it is the block, I'm still glass half full in that a stroker isn't too tough to build.
Not too tough. You'll pay the most for the machine shop work. I picked our parts out that I wanted and let the machine shop do the put together and install. We haven't had to run the bigger injectors or premium fuel, but depending on your elevation, maybe or you might hit ping city.
My brother and I had the machine shop assemble the short block for us too. We installed a cam(crane or comp?) and also bigger injectors. Honestly, I think the injectors had us running a bit rich, and we had to run premium. We never tried it, but I'm betting we could have run E-85 without adjustments.
If we did it again, we would pass on the cam and injectors.
What elevation are you at? We're just a SMIDGE above sea level and run regular ol CRAP through it. We *do* try to get the non ethanol though, although I doubt it makes much difference switching back and forth.
We won't do anything more to it till we regear and see where we are at then ( still running 3.73's)
We've got a Comp Cam with stock Valve springs. If we woulda went any more aggressive it would have cost us a tidy sum more for performance springs. We did spring for roller rockers, chromoly rods, forged pistons and dual billet timing chain though. Thought it best to upgrade the weak parts of the 4.0. So far with the zinc oil we're doing fairly well, despite a few CPS *oppsies* (Shear pin rattled loose)
Elevation was around 900ft. Honestly I think it was the injectors. They were 24lb from a Mustang Cobra if I remember correctly. Much too big.
Are those other items prone to fail? I have been lucky in that regard. Sounds like you have a pretty nice powerplant! Can you explain more about the sheer pin issue? I've never heard of this one before.
In all honesty, my ideal jeep engine build would be a 4bt :) I really wish the U.S. would lose the diesel stigma...
^^ You and my husband both. We have a '71 Chief that we want to go to diesel too. It's gonna be our BOV / tower. You might try going back to the 19lb. I've heard all over boards people having fuel issues with the 24lb ones. Some can run them nicely, but after lots of tweaking.
As far as the pin, there's a pin in the CPS that broke loose and vibrated. It was just a defect in the part. Our mechanics, drilled the hole a bit larger and used a better quality pin.
I don't think it's a known issue. What issue I hear of is sticky lifters or just outright CAM failure. Flat tappet engines NEED that zinc as a buffer and thanks to all the regs, they've cut down on how much is in oils nowadays.( Zinc doesn't seem to play nicely with the nice CAT's vehicles have nowadays)
You can still get high zinc oil from shops and additives as well. We run a non detergent oil with zinc added already.
Are you a member of Jeep strokers? There's lots of good info about building a stroker. Part numbers and everything included. Saved my butt when the shop needed some obscure bolt for the timing chain lol. (We have a '02 head on an '89 block. Caused all types of issues)
Sadly we don't have that jeep anymore. It was my brothers and he was starting a seasonal service business a few years back-so it made sense to free up a little cash for equipment. It turned out to be a very wise investment.
We built ours using info on a "From Junker to Stroker" article we found on google. It was an early 90's YJ, so we stuck with the electronics and got a donor block/head from a similar year. A crank from a late 80's 4.2 yj fit nicely, without any surprises. I'll keep Jeep strokers in mind should I ever get the opportunity again. For now, my stock 4.0 is hanging in there, knock on wood!
Sorry for the hijack Don-any updates?
The shop, Quanz Auto, went through it with a fine tooth comb while we were up at the cabin. Included was a block test, testing for combustion gases in the coolant. That came up negative; block and head are good. They even thought to ask if I had "re-chipped" the system; answer to that, No.
The only part in the cooling system I have not replaced is the mechanical driven fan clutch. It seems good and not just my opinion but that of serveral mechanics. However, Quanz told me two things that are interesting. Their experience with these is that if the water pump needs replacing and there are 100,000+ miles on the pump and fan clutch, you should change both the pump and the clutch no matter how good the fan clutch seems to be. And secondly, never buy an aftermarket fan clutch, get an OEM. So tomorrow I'll pick it up from Quanze, pay them their $80 diagnostic fee and stop by the Jeep dealer on the way home for a new fan clutch. Then I'll load the trailer with 100 US gallons of H20 and see what happens on the steep grade up the highway to the cabin.
Well at least it is not a new short block. ;D
So the new OEM fan clutch made no difference. :( I hauled a trailer of building materials that was no heavier than other loads I hauled before this trouble started over the weekend. The Jeep hit hot just like before at just about the same spot(s). The temperature sender is the only part not changed. However, the engine is definitely getting too hot. I had my infrared thermometer along and when the gauge alarm went off and the gauge indicated a temperature of about 250 F, the infrared gave me a reading of 248 off the thermostat housing right where the sender mounts.
Today I visited two more highly rated independent shops in ABQ. Both have been in business decades. There was a lot of head scratching going on and no definite solution. By consensus there seems to be a small chance of a malfunctioning thermostat. And one opinion that perhaps there is too much insect debris in the A/C condenser in front of the coolant radiator. So I removed the grill and blasted out the condenser at the car wash. We lost some of the black paint with that. So I repainted and reinstalled the grill. This afternoon after it has cooled I'll replace the thermostat, that's easy and cheap. Then tomorrow I'll try hauling a load of water up to the cabin; that never used to be a problem. With having installed a new fan clutch, radiator, radiator cap, hoses, water pump, thermostat, fan shroud and a re-manufactured head there is not much left to replace.
I may now have a better understanding how it is some folks end up with derelict vehicles parked in their yards.
I am seriously considering replacing the entire vehicle. I think I said once before that if this was a horse I would have shot it long ago. There are some nice Toyota Tacomas available.
Radiator has not been replaced I would look at that as well. I however dont think I would have it 'rodded out' I would be very concerned of leaks starting afterward. Have you priced a new radiator? The work horse it has been and the attempt to fix and what you are out already I would be tempted to go ahead and do that however there has to be an end.
We had a 10 year old Jeep Cherokee straight 6 that started to overheat. Radiator replacement did the trick.
Quote from: MountainDon on August 27, 2012, 02:14:15 PM
....having installed a new fan clutch, radiator, radiator cap, hoses, water pump, thermostat, fan shroud and a re-manufactured head ....
Note: the seventh word in the above quote is radiator.
signed: Exasperated!
Oh.....
Is it possible that sealent was used on the head gasket that could have flowed into the coolent passages and restricting flow?
Sorry MD but I did read radiator cap..... ;D I ask for a reprieve......
No sealant used, as per the Fel=Pro directions
Quote from: rick91351 on August 27, 2012, 06:29:56 PM
;D I ask for a reprieve......
not a problem.
Still exasperated, though (about the cooling). Or lack thereof.
Probably not it, but i had a friend once who had a similar seemingly unfathomable high temperature issue
He'd been sold the wrong fan for the truck and the fins were the pushing air out - rather than sucking in
Took him two head gasket jobs to solve it.
Does the lower intake hose still have the wire in it to stop it sucking flat ? my 6 cyl jeep had one
thermostat - just take it out completely - its not cold yet
run the engine with the to hose undone- got decent flow ?
For bleeding the system park on a hill and do it
Does running the heater on full lower the engine temp ? ie heater core is not blocked
Run a divertor hose and run without the heater core
Timing right ?
remove the water pump again and check the impellor is tight on its shaft and that the in and out ports line up with the block properly.
Thats about it from me !
I haven't taken mine out to see if I've corrected the issue but here is a question: what are the color of the plugs? Tailpipe? Have you changed out the O2 sensor recently? Before and after the catalytic converter? MAP Sensor?
I ask this because I think my problem wasn't cooling system related at all. Like you I replaced everything to no avail and continued to have issues except one difference: I had a PO171 code that kept coming up.
Before replacing the O2 sensor I noticed my K&N filter had nearly come off so I began to suspect a lean running condition which can cause overheating. I replaced the K&N (it was due anyway) and the O2 sensor and the Jeep is running much happier today.
I still need to replace the missing heat shroud and skid plate (both are supposed to help with the overheating issue) and if that doesn't work then I'm dropping the pan and replacing the oil pump and screen. Oil provides more cooling power where it counts anyway so if the screen is clogged (I do have 253,000 miles on it now) or the pump is getting worn/weak then no amount of water cooling is going to stop it from overheating under a load.
One thing I also need to do is replace the rear O2 sensor and map sensor and any pcv valves etc that need replacing...I know it too but just keep putting it off....the jeep runs great though and my wife often takes it to work (she's driving it today) but I haven't put it under a load lately to see if it still gets hot.
Last time it hit about 220 but it was 100-105 out and I had a bad O2 sensor and loose air filter so I suspect I've probably cured the issue already and don't know it.
No error codes. One O2 sensor is about six months old; something reached up and tore off the wire one day ;D
Stainless steel wire coil in lower hose.
No heater core blockage. Lots of heat available from there and super flow seen when hose is removed and engine run briefly.
I've had the replacement (new) water pump off and it is fine.
Cooling system has no air pockets or bubbles. Thermostat disk has 1/8" hole drilled in the disk, positioned at top, air bleeds past that just fine. Too small a hole to cause any issues with over-cooling or slow warm up.
Thanks all... I think I have thoroughly vented........
I don't know if you have emissions tests Don, but if you don't...rod out the catalytic converter.
I second the idea of leaving the thermostat out. I do that anyway on my 4WD's (Not the land rover).
Dang, Don, take all those new parts and wrap another Jeep around 'em.
My '99 Wrangler has been giving me fits.
Intermittent problem.
For months, every 2-3 tanks of gas it'd loose power, just chug, cough, spit under load, then snap out of it.
All gauges were dead nuts normal, no 'check engine' lights on, nuthin'.
Thought it might be the fuel pump, or hopefully fuel filter.....nada.
This morning, she sputtered again,
But
The 'check engine' light went on........finally!
Something to register on the ODB.
The 02 sensor
$50
20 minutes
Runs like a top
Hand cleaner
Dinner
Fat, dumb, and happy again
Now, after reading about your woes, if she ever overheats, gonna take the ol' gal on a rock climb...one way.
Peter, we live a few miles outside the nearest "emissions test area". However for years there has been talk about including us as there are loads of folks who drive from here on the high mesa to the polluted river valley that consists of a large portion of ABQ which is the reason there is an emissions test area. Anyhow that is not a problem as the cat passed the restriction test with flying colors.
Thermostat vs no thermostat. Well on the trip up to the cabin with the drilled stat, the Jeep pverheated more or less right where I anticipated. Once at the cabin, with 2 more stops for dribbling cool water over the rad exterior, I dumped the load of water in the cistern and let the engine cool. I decided to remove the thermostat for the trip back. I don't view this as a solution, just a crutch and a sop to my curiosity. The trip home showed some lower than usual temperatures as it is mostly downhill and the 830 lbs of water was left behind. Tonight though I pulled the #3 plug again. Instead of the light brown it has been it was more black. Not sure if I'll try a loaded trip with the stat removed? ??? I've already hung too many new parts. Scary thing is that a search for overheating XJ Cherokees in late model years (95 thru 01 more or less) brings up lots of guys with the same problem. Some threads seem to have been resolved with new rads, fan clutches, etc. But there are a number that simply stop with no stated resolution. I think for some reason the engine is producing more heat than it used to. It's very discouraging when after so much work and so many new parts that the XJ can not perform the same tasks it did for years. There is a hidden reason; well hidden. Normal about town driving and highway travel with no heavy loads can be done with little fuss. At this point I am weary of chasing the solution. There are a couple of local recent year Tacomas that are looking more and more attractive.
Looking for a RR X-ing to stall out on....
Speaking from experience! Do the railroaders a favor and don't do that! ;)
I am sort of wondering alcoholic - gas be a problem?
Long time ago we had a F-600 it started over heating we never found out why. We peddled it off and they put a new short block in and is running today. Can the block get garbaged up and not allow for proper circulation? After the F-600 I have alway wondered that.
I'd seriously consider the oil pump screen Don. If it's getting restricted, which can happen with age then it won't be able to provide the cooling that oil provides. Oil actually does more to cool the engine then water/coolant does though most wouldn't believe that.
Just imagine what cools the hottest places in the block (friction heat in the bearings). It's the oil. Which must be circulated well and efficiently and in enough volume to carry away the heat while lubricating the parts.
I haven't ever dropped the pan on an XJ so I don't know how tough it would be to drop the pan and remove the screen and clean it of sludge and crap but I'm willing to bet it would make a difference.
One way to check though would be to do this: Buy SLICK50, do an engine oil change and add the SLICK50...run your test again.
If it runs cooler with the SLICK50 when you're under a load I'll lay dollars to donuts it's the oil screen in the pan that's clogging up and reducing flow since the SLICK50 will be providing more friction reduction then normal the oil will be better able to cope with the temps.
I once drove a Ford Escort across the US pulling an MGBGT. When I first tried doing this (leaving Camp LaJuene after getting out of the Corps) the Escort just couldn't seem to do it. It would cut out and stutter and fail every time I tried to get up to speed in 4th gear. I changed the oil and remembering something my Dad told me from his sportscar racing days I added a quart of SLICK50 and whaddya know the dang stuff worked! I pulled that B across the USA at 70mph no problem! Never got hot either.
I left the B at my cousins in Eugene and went to work in Portland....some 10,000 miles after adding the SLICK50 and changing the oil etc I went back to get the car and pull it the 200 miles to Portland...and I couldn't do it! No way was that Escort going to pull that B again...stunned I unhooked and had to have my wife drive the Escort while I drove the B (with an open header) the rest of the way.
Got one heck of a head ache but loved the ride!
Anyway, something to try right?
All I can say Don...is that you have far more patience than I do! ;)
Quote from: OlJarhead on August 29, 2012, 12:11:40 AM
I'd seriously consider the oil pump screen Don. If it's getting restricted, which can happen with age then it won't be able to provide the cooling that oil provides. Oil actually does more to cool the engine then water/coolant does though most wouldn't believe that.
Just imagine what cools the hottest places in the block (friction heat in the bearings). It's the oil. Which must be circulated well and efficiently and in enough volume to carry away the heat while lubricating the parts.
I haven't ever dropped the pan on an XJ so I don't know how tough it would be to drop the pan and remove the screen and clean it of sludge and crap but I'm willing to bet it would make a difference.
One way to check though would be to do this: Buy SLICK50, do an engine oil change and add the SLICK50...run your test again.
If it runs cooler with the SLICK50 when you're under a load I'll lay dollars to donuts it's the oil screen in the pan that's clogging up and reducing flow since the SLICK50 will be providing more friction reduction then normal the oil will be better able to cope with the temps.
I once drove a Ford Escort across the US pulling an MGBGT. When I first tried doing this (leaving Camp LaJuene after getting out of the Corps) the Escort just couldn't seem to do it. It would cut out and stutter and fail every time I tried to get up to speed in 4th gear. I changed the oil and remembering something my Dad told me from his sportscar racing days I added a quart of SLICK50 and whaddya know the dang stuff worked! I pulled that B across the USA at 70mph no problem! Never got hot either.
I left the B at my cousins in Eugene and went to work in Portland....some 10,000 miles after adding the SLICK50 and changing the oil etc I went back to get the car and pull it the 200 miles to Portland...and I couldn't do it! No way was that Escort going to pull that B again...stunned I unhooked and had to have my wife drive the Escort while I drove the B (with an open header) the rest of the way.
Got one heck of a head ache but loved the ride!
Anyway, something to try right?
I haven't seen much sludge around pick up screens unless the engine was badly neglected and it would have sludge through out the engine. If the valve cover was fairly clean it most likely will have a fairly clean pan and screen.
I know the oil does much of the cooling. But I believe as diyfrank said, there would be traces of crud eldewhere too. The valve cover inside and the head top were pristine looking. Not a trace of any deposits or crud so I really doubt the plugged screen theory. Oil pressure reads good so there is flow. Oil filter reads okay temperature wise when the cooling system goes boinkers.
Rick I have been wondering the same thing... some loss of coolant flow through the block or a loss of ability to transfer heat from the iron to the coolant. But I draw the line at pulling the block. And even though I had little faith in it I tried a bottle of water wetter by Redline. Snake oil.
(and just kidding about the RRX. Decades ago in a blizzard back home I saw a car abandoned on the RRX. Always wondered if it was intemtional or what. Train never did hit the car.
Peter, I guess I do have some patience, but it's not inexhaustible. And I have said a few blue words. This started out as a simple problem. Then it became a challenge. Now it seems to have turned into a gamble; "You got to know when to hold 'em, know when to fold 'em."
Might be time for a new head?? Some of the older 4.0 heads would get hairline cracks in 'em. Supposedly the 2000+ heads stamped TUPY were better.
???
Course if you were pulling the head, might as well spring for a rebuild while she's down..
It's got a newly remanufactured head with the "good" casting number 0630, not a 0331 which is susceptible to cracking between #3 and #4. Thanks for the input.
FWIW and FYI, late '99's can have the 0331 head, 96 thru earlier 99 have the the 0630.
Don, do both heads read the same temp with the IR Gun? What about the exhaust manifolds?
Measure the radiator inlet and outlet temps too. Check the differential... too bad you don't have another jeep to compare it to.
It was mentioned before.. but I wonder how it might be possible to check the fuel mixture. ???
Has your fuel economy changed at all?
It's an inline :)
There is a temperature drop from radiator in to out. I forget the numbers but Quanz, Moneysworth and Walton all measured and state it's fine (when it's sitting there.)
It uses pretty much the same amount of fuel for a trip to and from the cabin as always. That's not a very accurate measure. An old meter I have from the EFI CJ days indicates the mixture is within allowable limts. Quanz also ran a probe and said it was okay. Plus the OBD is clean as a whistle.
[crz] [noidea' [noidea' [noidea' [noidea'
Missed out on one Tacoma TRD today :( but there's another I'll be checking on tomorrow. A little older than my ideal but then it is also cheaper. And it has the factory tow package = 6500 lbs tail.
In the meantime I may rig the chemical sprayer I used to use as a misting, evaporative cooler for my personal comfort (don't worry it was brand new, never saw any pesticides, etc.) in the old CJ as a misting cooler for the XJ radiator for a trip to the cabin.
Don,
What a frustrating experience! First of all, you need to get a better tool set; I just have a $300 Crescent set that is about a 275 piece set and I have a 12 pt 13mm in 1/4 and 3/8, oh, but none in deep 12 pt....Sounds like a good excuse to upgrade!
I don't understand your concern with removing the thermostat; there is nothing to possibly be damaged. Their original function was only to provide heat to the cab, but in recent years has been a way to keep emissions lower by always having the engine temp hotter, but running without one for a short time won't damage anything, just take longer to heat up.
On the oil pickup screen idea, hanging on to this as the only thing I can see as plausible, it could be dirty/clogged while there is no sign elsewhere of crud as something may have possibly come down the filler, unlikely but possible, into the case with as goofy as Jiffy Lube techs are.
You can't sell it; you need to hang on to it just to give us closure on this. Can you feel the flow through the hose? Does the IR gun show much cooler temps on the lower hose vs top (signifying flow)?
Before I say my next line, I have a Dodge with 140k miles with only a water pump and a new ignition cylinder in 8 years of ownership, pretty dang good vehicle, but in my 10 or so years of working auto parts the Chrysler stuff had by far the most number of people swearing them off to never own one again...I am sure that is all much better now that Obama and the UAW are principle shareholders, I can't think of anyone better than the fox to guard the hen house!
Have you tested the T-Stat? Boil tested it? Or did you replace?
http://www.summitracing.com/parts/BRA-1747/
Some say this is the way to solve the problem. High volume/flow water pump. Some claim it will keep the 4.0 running 195 all day long in heavy conditions -- folks that had overheating issues previously like yours.
http://www.lunghd.com/Tech_Articles/Cooling/BurpAirMod.htm
Some say that it's often air bubbles caught in the head that cause the problem. Have you burped the system?
I know the feeling on thinking about selling. I was seriously considering a Ruby a few months back but I'm glad I held off in the end because the XJ is running well today and I have a truck for cabin trips where I need to tow ;)
Well Don.... ???
I'm still thinking it's a simple problem. It's a simple engine and I swear mine is probably still chugging along or the fellow I sold it to.
The only suggestion (and you've done it on the way back) is pull the thermostat out, don't worry about the blackened plug (I always go up one heat range or so on the plugs after I take the Tstat out)....and see if it overheats with a load like it did before.
That will at least narrow it down if you don't want to leave the thermostat out.
The thermostat opens. Starting from cold I can watch the gauge climb and then tick back a notch. This coincides with the top rad hose getting hot all of a sudden, followed by the radiator heating up. The 'stat is removed at present, and I'll see what happens. I can already see it runs much colder about town on the typical short trips here. The computer doesn't like it as seen by the indication of a rich mixture. Maybe I'm being stubborn but it ran perfectly well for the 11+ years we've owned it. Until now. With all the new parts it should run the way the factory designed it.
Flowkooler water pumps are great for slow crawling. That is where they shine. Flowkooler themselves states that the flow is much greater at idle rpm's. By the time engine speed rises to 3500 rpm's the flow has slowed back to normal specs. I don't know how that is done, but that's what they say. "At idle our pumps pump more than twice other pumps and we outflow "performance" pumps by 20%. At 3,500 rpms, the gallons per minute flow rates level off to standard flow rates. " My issues are happening at the higher rpm's; 3000+ when it's working hard. I'm usually running 3000 rpm;s up the approach to the high point. After enough of that the gauge jumps to hot as the alarm sounds. Water flow from a Flowkooler is pretty much in the factory pump range at those speeds. Hesco also has a HD pump; I'm not sure of it's flow rates, but it even more money.
Back to the thermostat and burping. I used to loosen the top bolt on the t-stat housing when refilling the system. I could hear a pffft- pffft as air escaped. Since trying the hole drilled in the stat trick loosening the bolt only gets fluid. The hole does pass the air. There are some stats available with a factory made venting hole. FYI, I usually work on cooling systems on the section of my driveway that permits parking with a distinct nose high tilt. Ideal for assisting in burping through the front end. Some 4.0's have the sensor fitting in the head at the rear. Mine does not; it is factory mounted in the t-stat housing at the front.
It's never knocked or pinged. Never seen any indications of pre -ignition from plug readings, ever. Been looking for that now but, nothing. I pulled the distributor a while back and it checks out on a test bench. Followed the factory installation from the factory service manual. The ECM does all the work after that.
So yes I agree that the solution might be a simple one, but a simple one that is very elusive. Right now it's a lot like a girl friend or wife who has let you down, cheated on you, stolen some cash or whatever. I have lost my trust, my faith. Unlike a girl friend or wife the XJ is an inanimate object; it can not love me back. I have no brand loyalty. I know, "Jeepers" will all gasp collectively at that blasphemy. But really, it is just a machine. I've owned over a dozen different brands of automotive machines in my lifetime, some more than once. There are very few I truly miss for one reason or another.
(https://i139.photobucket.com/albums/q305/djmbucket/vehicles/P1050309sml.jpg)
'06 Toyota Tacoma TRD Off Road package (includes locking rear diff, skid plates) and the factory towing package.
To pretty to take four wheelin' or even to the cabin [cool]
Quote from: rick91351 on August 30, 2012, 07:27:04 PM
To pretty to take four wheelin' or even to the cabin [cool]
Yep! ;D
I wonder what the difference in gas mileage will be. I think it was you Rick, that commented about it getting to be a major expense. Me too. Round trip about $60.00 now.
FWIW, the EPA figures for the Tacoma is 1 better on the combined and the highway side, 2 better on in town. :-\ Jeep highway 19 and Tacoma highway 20. The trip to CA in early June returned an average overall of 18.9; maximum highway speed about 65 mph. The Jeep weighs more than the average XJ one because of the bumpers, tire rack, skidplates, larger tires and so on. (gearing change corrects to be very close to stock as far as engine rpm's per mile. I've talked with one Tacoma owner who has a shell on the bed like ours and he says he gained nearly 2 mpg when he added that. So we'll see.
The shell did help my old 78 F150.
Quote from: rick91351 on August 30, 2012, 07:27:04 PM
To pretty to take four wheelin' or even to the cabin
Not as pristine as the first impression.
(https://i139.photobucket.com/albums/q305/djmbucket/vehicles/P1050311sml.jpg)
Quote from: MountainDon on August 31, 2012, 08:38:22 AM
Not as pristine as the first impression.
(https://i139.photobucket.com/albums/q305/djmbucket/vehicles/P1050311sml.jpg)
If you're saying that's not pristine Don...I'd best not show any pictures of my Bronco. :-\
Now I have the dilemma of what to do with the XJ. It's not right to knowingly offer it for sale without mentioning the issues it's having. Now that I have wheels that work again perhaps I'll have to pursue a solution a little longer. Or accept bottom dollar for a vehicle with known problems. :-[ :(
Nice truck, Don. Too bad the Jeep is being such a bear. I have had similar problems in the past and also got tired of looking for the cause....[ouch]
don i have seen those high flow pumps cause problems at speed. they cause cavitation at higher rpms
The XJ is not overheating for me any more. :)
It is now overheating for someone else. ;D Full disclosure was made so he knows the entire story and was willing to absorb the risk.
That fixes it.... :) :)
Postmortem...
After talking with one of the area's better custom engine rebuilders I have a probable cause for the overheating. We have hard water with a high pH. It should never be used to dilute concentrated antifreeze. I was told that after many years of using regular antifreeze like green Prestone, mixed with our water (50/50 mix) it is not uncommon to see vehicles begin to show overheating problems. A scale can build up on the inside of the cooling passages. This apparently happens with greater frequency with all iron blocks and heads. The hotter the engine runs the more the scale can deposit out of the coolant and stick to the iron. The higher thew pH the worse the problem. A 1/16" layer of build up can slow heat transfer by 40%.
The preventive solution is to use either the pre-diluted antifreeze that is available, or to buy distilled water to mix with the concentrate. The solution at this point is to pull the engine, diassemble the block, take that to a good rebuilder who has the equipment to descale the internal water passages and then reassemble. Or simply install a re-manufactured block. He said that trying to descale the engine with cooling system cleaners does not usually work.
I knew there were good reasons to not drink our tap water. So we'll continue to drink reverse osmosis filtered water and probably simply buy the 50/50 pre-diluted long life coolant such as what the new Toyota has in it.