So i think my head cracked AGAIN!!!! - JeepForum.com
 
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post #1 of 10 Old 06-15-2015, 09:33 PM Thread Starter
juicebox11
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1996 XJ Cherokee 
 
Join Date: Mar 2014
Location: greensboro
Posts: 19
So i think my head cracked AGAIN!!!!

Ok so heres what happened and i would love some feedback on what yall guys think may have happened as well.

first the basics.
Jeep Cherokee Country 4.0 with auto
throttle body spacer and cut exhaust
no other engine mods
5 inch lift on 33's
stock gears

went wheeling the other day and jeep did fine all day. i had even wired my e-fan to a switch in the dash earlier in the day so i could cut it on and off when i wanted because my 4.0 always runs hot.

well the jeep ran great for about 2 or 3 hours of wheeling and then on the last time i hit the mud hole and was crawling back up the trail steam blew out from under the hood and the temp gauge was near 250.
cut the jeep off and sat in the trail for about 15 or so min to let it cool and then drove it home. jeep ran a little hot (maybe 230-240ish) on the ride home but it was only maybe 3 miles at most.

got home and let it sit for about 4 hours and took off again to go meet some friends.

wile going down the highway steam blew out again but this time my gauge instantly pegged at around 260 275 ish. the engine also died out.

pulled over and let it sit. after about 30 min of sitting i tried to drive it back home since i was less then a few miles away but half way it died out again and teh gauge pegged.

thats where i left it untill the next morning.

when i got it the next day it started and ran fine but after only maybe a mile the gauge pegged again and it cut off just as i was pulling into my drive way.

somehow i ran the block out of water but the rad. was still full.
when i went to fill it back up later that day the rad was full but my gauge was still pegged. except for that my scanner that reads live data told me the coolant temp was only 130. then when it got hot enouigh for the thermostat to open it instantly drained the rad and the gauge inside the dash dropped to 175.

now that everything is full again the jeep runs good at idle but is constantly bubbling out of the rad and the level rises and falls constantly.

sorry for the long story but what do u guys think. in all my years of turning wrenches it is acting to me like a cracked head or blown gasket. however i have never seen a 4.0 gasket blow. just the heads crack.

what do yall think might be up with it???????

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post #2 of 10 Old 06-15-2015, 11:22 PM
HwyPilot
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1996 XJ Cherokee 
 
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Location: Osage Beach
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I'd borrow a pressure test kit and see what pressure does to it, it sounds odd alright, leaking freeze plug? The fact that your temp gauge is going bats, and it cutting out falls in line with what these do when overheating (start dropping cylinders due to heat detonation). Even a slight pressure leak and you're pretty much screwed with boil over. Can you tell where the lost antifreeze is going? Any trails left anywhere on the block?

In a pinch, the high dollar red coolant Toyota uses leaves a white deposit trail at leaks, I've used that before for some serious "magic leaks". The good part? It's running, so it doesn't sound like it's all leaking into a cylinder - that said, have you pulled and checked your spark plugs for contamination, and how's your oil look?

BTW, if your block is dry (empty), the gauge sender at the rear of the head will send some off the wall signals, they're made to read liquid temp, not air temp. Your ECU output is reading the sensor at the T-stat housing.

Besides the steam issue (freeze plugs are really making me wonder at this point), it almost sounds like the difference between your ECU temp output and your gauge is a stuck T-stat.
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post #3 of 10 Old 06-16-2015, 07:42 PM Thread Starter
juicebox11
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Location: greensboro
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sorry been swamped with work and side jobs at the house. but i probably should have said in the first psot that i did check the oil and from the dip stick it looks clean. i have my pressure tester here at work with me and will bring it home tonight and test the system on the xj.

their are also no visable leaks on or around the head or water pump either. but when i looked at it the other day it was around 97 degrees outside so i didnt spend much time checking.

im going to test a few more things tommorrow and get back to yall with what i find. pretty sure as soon as i finish this water pump job on a zj ill be pulling it it to pull the head though.

also its a 96 but i bought it for 200 bux with a cracked head and ended up putting a 98 head on it because i couldnt pass up on the deal. so i know these newer heads are bad about cracking. which is why im thinking head problems
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post #4 of 10 Old 06-16-2015, 08:02 PM
CEScuzzy
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Quote:
Originally Posted by juicebox11 View Post
sorry been swamped with work and side jobs at the house. but i probably should have said in the first psot that i did check the oil and from the dip stick it looks clean. i have my pressure tester here at work with me and will bring it home tonight and test the system on the xj.

their are also no visable leaks on or around the head or water pump either. but when i looked at it the other day it was around 97 degrees outside so i didnt spend much time checking.

im going to test a few more things tommorrow and get back to yall with what i find. pretty sure as soon as i finish this water pump job on a zj ill be pulling it it to pull the head though.

also its a 96 but i bought it for 200 bux with a cracked head and ended up putting a 98 head on it because i couldnt pass up on the deal. so i know these newer heads are bad about cracking. which is why im thinking head problems
Only the 0331 heads from the 2000 and 2001 models have a real cracking issue; I've not heard of people having much trouble out of any of the others.

"Some Assembly Required" is a target, not a deterrent.
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post #5 of 10 Old 06-17-2015, 05:41 AM
tjwalker
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Quote:
Originally Posted by juicebox11 View Post
also its a 96 but i bought it for 200 bux with a cracked head and ended up putting a 98 head on it because i couldnt pass up on the deal. so i know these newer heads are bad about cracking. which is why im thinking head problems
The 98 head should be the 0630, which is not the 0331 which has the factory casting defect.

You should also perform a simple compression test. It's one of the best tests for determining if you have a cracked head gasket.

99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche
Without "data", all you have is an opinion!
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post #6 of 10 Old 06-17-2015, 03:03 PM Thread Starter
juicebox11
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ok so heres some news. i put my pressure tester on the coolant system and put 15 pounds on it. i left it on the entire time i was mowing which was about an hour and a half and when i came back. it was still dead on 15. so maybe the head isnt cracked. i have to find a compression tester to check that TJ but tommorrow im going to pull all the plugs to see how they look. i also want to check the coolant pressure again wile the jeep is running. by everything ive checked the past couple of days its looking like its not cracked however it will still bubble out of the rad. when its running. which i guess it could just be one heck of an air pocket slowly working its way out. ill check back again tomorrow and let yall guys know what i find.

and sorry i thought it was all 98 and up heads that were the 0331 heads. didnt know those only started in 2000
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post #7 of 10 Old 06-17-2015, 03:37 PM
CEScuzzy
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Quote:
Originally Posted by juicebox11 View Post
ok so heres some news. i put my pressure tester on the coolant system and put 15 pounds on it. i left it on the entire time i was mowing which was about an hour and a half and when i came back. it was still dead on 15. so maybe the head isnt cracked. i have to find a compression tester to check that TJ but tommorrow im going to pull all the plugs to see how they look. i also want to check the coolant pressure again wile the jeep is running. by everything ive checked the past couple of days its looking like its not cracked however it will still bubble out of the rad. when its running. which i guess it could just be one heck of an air pocket slowly working its way out. ill check back again tomorrow and let yall guys know what i find.

and sorry i thought it was all 98 and up heads that were the 0331 heads. didnt know those only started in 2000
No problem, just keep us posted! New cooling problems are always frustrating to deal with.

"Some Assembly Required" is a target, not a deterrent.
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post #8 of 10 Old 06-26-2015, 03:01 PM Thread Starter
juicebox11
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so heres whats been going on with the jeep. the day i tested the coolant system i let it run and idle for about two hours and it did fine. a couple days later i drove it to the store and back and it did fine. so yesterday i pulled all the plugs to see how they looked. all six plugs look perfect and every clyinder looked clean from what i could see. so i drove it around and to work and back that day and it ran good. it still seemed to run a little hot after a wile but only when i got stuck in traffic. plus it was 97 degrees here so i think it would have honestly ran hot when its running its best.

So with that being said maybe the heads not cracked and i just pumped every drop of coolant out of the rad when it overheated. and if it is cracked its way to small to worry about right now. it will be stroked in 6 months or so.

i was going to do a compression test when i checked the plugs but after running it to warm it up i burnt my hand getting the first plug out and said f*** it and jsut drove it. so i dont know exactly what the compression is. but it has passed every other test ive done on it.
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post #9 of 10 Old 06-27-2015, 04:14 PM
HwyPilot
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One thing I ran across on another thread here was a "mystery leak" that was the freeze plug inside the trans bellhousing at the back of the block (and I thought SOB I would lose my damn mind if I had that going on....). The tell-tale to that was coolant dripping out the bottom of the bellhousing, but yours seems to hold pressure....

Compression tests are kind of a biatch on some engines, and I'm no expert, but anything with an angle boot can be "fun" getting compression readings down. They are important, and should be done cold, due to burning the hell out of yourself on a hot engine.... A remote switch, compression test set with the right angle fittings, and you're golden - but it sounds like it's done it's thing for now - as odd as it sounds to me.

Nothing occupies my head more than the "what ifs" - like the Neutral Safety Switch throwing fits on my spare RHD XJ intermittently.... She needs an emergency start switch (another fine factory design "skip" - most vehicles have an over ride). It's hot as hell here too, and I've got too many older vehicles with issues and no garage space yet - I feel like a one legged man in a butt kicking contest at times.

Let's hope it's shot it's load and done - I'd suggest running cooling system cleaner and distilled water through that thing for as long as the directions (and you) feel safe doing so, then dumping it, rinsing (running) the system with distilled water, dumping it again (lower radiator hose if you can stand the mess) and then refilling using less antifreeze and more water, maybe even water wetter as an additive (I've done that in the spare XJ for now, with 50/50 mix, it does seem to help) - or having the system flushed and filled on a machine. These iron blocks junk up the system over the years, and the crap I saw come out of the '96 RHD with 60k original miles was mind blowing.
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post #10 of 10 Old 06-27-2015, 04:22 PM
HwyPilot
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Here's what I was referring to running more distilled water in the ratio - depending on your climate - 50/50 is not ideal and doesn't cool as well. http://hellafunctional.com/?p=629

It also doesn't hurt to rinse your grille area out with a garden hose for about an hour with it cooled down - no pressure nozzle - just run water out of the hose through the grille area - you'd be surprised at what a wasps nest of mud build up can do to create issues. A friends 18 wheeler had some seriously random cooling problems at speed and load, and after a full day and $800 at a shop, it was still doing the same thing. A fellow trucker told us to run a hose through the grille for an hour when we could (we were driving team, so the truck never stopped) - a bunch of crap fell out after about 45 mins, and the problem disappeared - for now 500,000 miles and counting....
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