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Blown head gasket?

T

true2blue92

NAXJA Forum User
Location
Las Vegas, NV
I hate to keep posting, I've searched and found alot on the subject nothing similar to my problems though. Whenever I park I'm leaking what seems to be coolant. This morning there was a huge puddle and all my coolant is gone. It's coming from near the oil pan but it seems like it's something above that. I checked the oil and it isn't milky. And there's no white smoke coming from my exhaust. I'm not exactly what to do from here. The jeep does have overheating problems so I ran a switch to the Aux fan and as long as I watch it and turn the fan on when needed it hasn't overheated lately. Although when I first got the jeep it would overheat like crazy due to the Aux fan not turning on and whatever else is wrong with the cooling system. I'm just getting overwhelmed with problems and Im not sure what my next step should be. 89 4.0 auto 225,000 miles
 
One place sometimes over looked is the jacket plug on the back of the engine. You said oil pan but not where. If it is toward the rear it is a possibility. Just a suggestion.
 
Job #1 is to find the leak.

I'd suggest getting it up on a hoist, warm up the engine so it is pressurized, use a good light and perform a comprehensive search for the leak. You should be able to find it.

If not, run a "cooling system pressure test". If you don't have the equipment, you can rent it from some parts stores, OR a shop will do this pretty inexpensively.

Gotta isolate and fix that leak! Even if it means paying a shop to help you with it.
 
Yeah its toward the rear of the engine. Somewhere above the oilpan. My dad seems to think maybe the freeze plugs. It got into the 20s or so last night. I'm stuck in deciding what to do. The engine overheats it has oil on the air filter. Just numerous problems. I was looking at reman engines and they're like $1200 I'm thinkin about just buying another jeep possibly. I don't know I don't really have the money to do either but I need a car.
 
Yes, could be a freeze plug leak.

The oil in the air filter is a common problem with your vintage. A lot of times it can be managed by refurbishing the crankcase ventilation system. Those parts get clogged and brittle with age. SEARCH on this forum and on the internet for more.

The overheating of course has multiple suspects including radiator, water pump, pressure cap, thermostat, fan clutch. Would need more details on how/when to help you there.

All of this depends on how much of this you can do yourself and how much you love your Jeep.

Good luck with your decision.
 
Best bet to find a leak is to use the coolant pressure test pump to pressurize the system. That way you can get up close to everything without getting burnt or cut by the fan.

A compression test is very useful to determine the overall internal condition of the engine for making decisions about the future.
 
Compression test is a good idea. Havnt thought about that. Would that tell me if the head gasket is bad?

I am able to preform most of the repairs on the engine myself so that's not a concern. I would like to get all new cooling system parts, radiator, water pump, thermostat, fan clutch, etc. I'm just trying to decide if I should put the money into it and then only to have more problems with it in the future. I've already put about $300 or so into basic maintenance stuff since I got the jeep so I don't really want to give up now.
 
How much in "all gone"?

If it is just the pressure bottle being empty then I would recommend you replace the cap first and then check things.

Yes, there are Welsh aka freeze plugs on the back of the engine and under the manifolds. Here is a link to GoJeep's article on the 4.0 plugs: http://go.jeep-xj.info/HowtoWelshPlugs1.htm

If your pressure bottle cap is loose you will loose a lot of coolant because without pressure the boiling point of your coolant is much lower.

If your cap is "stripped", i.e., when you try and tighten it all the way down it "pops" on the threads, then you need to replace that cap with a Stant 10244 cap--it is a cap from a Volvo 2.3L engine and it WILL SEAL without stripping.

EDIT: you should fill the system and purge the air so that ONLY 1/4 of the pressure bottle has coolant when COLD. The rest of that room is for coolant expansion.
 
If your gonna get all new cooling system parts, might as well convert to the open system of the newer cherokees. I used to think i had a blown headgasket, my jeep used to overheat in traffic all the time because of that XXXXing pressurized expansion tank! I changed to the open system and havn't had a problem since. It's the best project i've done highly recommended!
 
t.loretto said:
If your gonna get all new cooling system parts, might as well convert to the open system of the newer cherokees. I used to think i had a blown headgasket, my jeep used to overheat in traffic all the time because of that XXXXing pressurized expansion tank! I changed to the open system and havn't had a problem since. It's the best project i've done highly recommended!
Click to expand...

Or you could have bought a better cap and saved about $150-200 dollars.
 
I bought several different caps. All fit and vented properly, but there's about a million different things that can make that system overheat, it's just a bad design
 
t.loretto said:
I bought several different caps. All fit and vented properly, but there's about a million different things that can make that system overheat, it's just a bad design
Click to expand...

Really?

Cap that won't seal will cause both a closed and open system to overheat.

Bad fan clutch will cause both a closed and open system to overheat.

Not using the correct coolant mix for the ambient temperatures of the season will cause a closed and open system to overheat.

Not fully purging all of the air out will cause a closed and open system to overheat. (BTW--there are a LOT of open systems that can't self-burp.)

I would go on, but other than ONE SINGLE ISSUE both the open and closed systems will overheat due to the same causes.

Do you know what that ONE ISSUE is?
 
Should I assume it's the freeze/welsh plugs or try and find something else. The reason I think so is the guy before never added coolant he just added water when it was low. I have since added some 50/50 mix but never got around to flushing the whole system and filling it with the proper mix. So there was probably something like 80/20 water in there. It's never leaked before until just the other day when it got in the 20s.
 
Easy answer. NEVER ASS U ME. Test. Get a pressure tester and find the leaks.

Now you have thrown in another strong clue to the whole problem. Weak antifreeze and below freezing temperatures. Ice is very strong and could have broken anything. Maybe it did pop a "freeze" plug. BTW, those are not really "freeze" plugs and were not designed to help prevent damage when freezing. They are actually core plugs. The only reason they are there is to clean out the core sand from the casting process.

Bottom line is the same. Find the leak.
 
Oh ok thanks. I was under the impression they popped or broke when they froze to prevent internal damage.

Well I can rent a pressure tester from autozone. Do I fill up the system with water and the pressurize it and find the leak? The only thing I'm concerned about is wherever it's leaking I can't see it and would have to pull my whole intake mani and exhaust. So should I just go ahead and do that first then go get the pressure tester?
 
Hey guys, took off the intake and exhaust manifold yesterday. Found that someone previously replaced the rear freeze plug with a rubber piece of junk one. And also that the second one was leaking just minor. I'm stuck trying to decide whether I should replace all five of them on the side or not. I want to since I have it all apart but there's also the don't fix it if it's not broken. So what should I do? I'm just worried that I'll change em all then one that wasn't leaking will start to. What do you think?
 
This is definitely one of those "You are in there already so fix the whole thing" situations.

Go to the GoJeep link I posted earlier. Do the job right and you won't have to do it again--at least for some 20-odd years or so.

Because you have issues I would pull the engine and do those in the rear of the block and head. Yeah, lot of work, but a whole lot of peace of mind will come from doing them all.

Good luck.
 
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