LR4 - Coolant Under Pressure When Cold

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RoverTide

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head gasket... sorry to be the bearer of bad news. these are all just classic bad head gasket symptoms. I believe you can buy a tester kit to put on top of the expansion tank and it will turn a fluid a certain color if there are exhaust gasses in the coolant. thats the first thing I would do, but others might have better advice.

the white smoke out of the exhaust is normally a key indicator.
The results are in... exhaust gas test turned yellow pretty quick. I'm not happy. Looking for next steps to determine solution. I assume a compression test is in order, but hoping you guys can help me get a game plan together, as i may be out of my league on this one.
 

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Jimmy Brooks

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The results are in... exhaust gas test turned yellow pretty quick. I'm not happy. Looking for next steps to determine solution. I assume a compression test is in order, but hoping you guys can help me get a game plan together, as i may be out of my league on this one.

I’m really sorry about the news. That’s super unfortunate to hear. Did you ever notice any over heating issues?
 

RoverTide

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I’m really sorry about the news. That’s super unfortunate to hear. Did you ever notice any over heating issues?
Yeah... I had a feeling this might happen at some point, but was hoping to get a few more years out of it before I put it out to pasture. Its such a beautiful vehicle. It never over-heated on me, always ran great. However, I bought it knowing it previously had an engine failure, which was most likely caused by coolant loss and resulted in an overheat. Engine was repaired with one new head, timing chains, cooling system parts, catalytic converters, etc. I knew it was a gamble... and, ultimately, it didn't work out. Win some, lose some.

If I had more space, I would park it and tear down the engine to see if it could be saved, but I am most likely going to have to get rid of it as-is. Not interested in spending $20-30k on a new engine. Trying to research options now.
 

M32H32IS

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Used engine prices have come down, and remans are around 12-15k installed.
 

RoverTide

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Used engine prices have come down, and remans are around 12-15k installed.
Thats good to hear. Curious where you are seeing those prices. I was looking around and most remans were between $10-13K for the engine only.

As an update... I extracted some oil yesterday, and there doesn't seem to be any coolant in it. i.e. its not milky... looks like regular oil. Going to do a compression test tomorrow and see if I can glean any info for a better diagnosis. Am I crazy to think that it could just be a cracked head since there is, seemingly, no coolant in the oil? I would think that if I had a blown head gasket or warped head, the oil would be contaminated. Would love to hear from guys that have experience with this sort of thing on other things I should test or look at.
 

greiswig

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I'm kind of curious what you mean by "just" a cracked head? I would prefer the blown head gasket, personally. ;)

My limited experience with both indicates that it's very hard to tell the difference between the two until you get the head off the block. Even then, you only can eliminate one (the cracked head) as the culprit. I had a Unimog engine where I kept getting oil in the coolant, and I never did figure out what the source was. I imagine it was a block defect somewhere in the high-pressure part of the oil galleys.

Anyway, no coolant in the oil might just be a sign of how small the leak is currently. As it grows, you might start to see more evidence of coolant in the crankcase. A compression or leakdown test might help identify what bank the issue is in, and possibly even what cylinder.

I'll just throw this out there, probably much to the consternation of many: I had one engine where it was not worth it to me to tear it down and do the repair on the cylinder head. I didn't know whether it was the head gasket or the head itself, and it didn't really matter to me. So I bought some block seal chemical and put it in the coolant, ran it for awhile that way, then flushed the system. That engine ran fine, with no further evidence of leaks, for 30k miles or so. But it was a Toyota, so...it had that going for it.
 

RoverTide

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I'm kind of curious what you mean by "just" a cracked head? I would prefer the blown head gasket, personally. ;)

My limited experience with both indicates that it's very hard to tell the difference between the two until you get the head off the block. Even then, you only can eliminate one (the cracked head) as the culprit. I had a Unimog engine where I kept getting oil in the coolant, and I never did figure out what the source was. I imagine it was a block defect somewhere in the high-pressure part of the oil galleys.

Anyway, no coolant in the oil might just be a sign of how small the leak is currently. As it grows, you might start to see more evidence of coolant in the crankcase. A compression or leakdown test might help identify what bank the issue is in, and possibly even what cylinder.

I'll just throw this out there, probably much to the consternation of many: I had one engine where it was not worth it to me to tear it down and do the repair on the cylinder head. I didn't know whether it was the head gasket or the head itself, and it didn't really matter to me. So I bought some block seal chemical and put it in the coolant, ran it for awhile that way, then flushed the system. That engine ran fine, with no further evidence of leaks, for 30k miles or so. But it was a Toyota, so...it had that going for it.
Legit question... and my logic is basically that if the head has a crack and no coolant has degraded the oil, then it is less likely that there are deeper engine problems caused by the engine running with degraded oil. This helps me rationalize the idea of repairing the engine instead of replacing or selling for parts.

Just understand that this is the logic of a broken man trying to figure out how to avoid telling his wife we just threw $12k down the drain.
 

RoverTide

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Wanted to post the compression test results and see if any of you have some thoughts on whats going on. This was done on a cold engine with the throttle plate closed. Overall, the compression doesn't look too bad. Cylinder 4 is the somewhat of an outlier at 158 psi, still not completely out of whack from the others though. I was expecting it to be worse.

So, I have exhaust gas leaking into the coolant, no coolant in the oil, and compression seems ok. Anyone have any thoughts on what that means or what I should do next?
 

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greiswig

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How quickly did the cylinders leak down? And did you spray any oil into them?
 

RoverTide

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How quickly did the cylinders leak down? And did you spray any oil into them?
Didn't realize that should/could be checked with a compression test, but can do that today. I did a dry test, no oil.

So, let me get this straight... Spray some oil in them, run the compression test again, and see how fast the pressure leaks down? Am I seeing how much pressure is lost over a specific amount of time, or am I seeing how long it takes to lose a certain amount of pressure?

I think I will run a borescope down in the cylinders and take a look first, then put some pressure on the cooling system, and run the borescope again to see if I can see any coolant dripping into the cylinders.
 

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