Jeep Head

[peternap]

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.

[UK4X4]

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

[Tinga]

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

[OlJarhead]

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 

[mgramann]

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.

[Tinga]

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.

[mgramann]

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.

[Tinga]

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)

[mgramann]

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...

[Tinga]

^^ 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)

[mgramann]

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?

[MountainDon]

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.

[rick91351]

Well at least it is not a new short block.   

[MountainDon]

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.

[rick91351]

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.

[kenhill]

We had a 10 year old Jeep Cherokee straight 6 that started to overheat.  Radiator replacement did the trick.

[MountainDon]

....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!

[kenhill]

Oh.....
Is it possible that sealent was used on the head gasket that could have flowed into the coolent passages and restricting flow?

[rick91351]

Sorry MD but I did read radiator cap.....   I ask for a reprieve......

[MountainDon]

No sealant used, as per the Fel=Pro directions

[MountainDon]

  I ask for a reprieve......

not a problem.
Still exasperated, though (about the cooling). Or lack thereof.

[UK4X4]

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 !

[OlJarhead]

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.

[OlJarhead]

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.

[MountainDon]

No error codes.  One O2 sensor is about six months old; something reached up and tore off the wire one day

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........