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Do I have a blown head gasket? What do I do now?

Hi everybody, I recently bought an 87 Suzuki Samurai. I’ve always thought they were cool and I’ve heard they are great cars to learn more about mechanics which is more the reason I bought it. I’m not that knowledgeable with mechanics yet so speak to me like I’m an idiot! Anyways, I’ve been fixing it up and learning a lot but now I’ve found some more major work that I’m not sure how to tackle. I think I may have a blown head gasket…but, I’m not sure. I’ll list my cars symptoms below:

-smoke from the exhaust at startup - stops after a few minutes of running

-coolant in radiator starts bubbling with the lid off when I turn the car on - lots of tiny bubbles

  • coolant in the oil - not a ton but its there

  • milky sludge on the oil cap

  • loss of coolant, even when not running. I’ve stopped running it since noticing this leak. Seems to be internal, can’t find any signs of exterior leakage.

So, I’ve been doing some tests to try and isolate the problem and now I’ve confused myself… I did a compression test. All 4 cylinders were consistent and within spec. The compression consistently rose slightly between a wet and dry test with all 4. I did a leak down test and, according to my tester, there wasn’t much leakage. I thought for sure when I hooked up compressed air that I would get bubbling from the radiator cap but there was nothing… I listened to the oil cap/dipstick, exhaust, intake and the radiator with the air hooked up. There was some air coming from the oil cap which I’ve heard is somewhat normal and could mean worn rings.

My plan had been to get a gasket set and replace everything down to the head gasket but these tests have me confused. Why is my compression good and the leak down test came up fine? Could it possibly be a bad intake manifold/gasket? What else could it be? Or does someone think its still the head gasket?

I’ve got a straight edge and feeler gauges so I’m going to check for warpage on the block/head when I take it apart. Other than that I’m not sure how to isolate and find the problem…

Anyone have any thoughts on what is wrong with the engine? I’d love to have some more expert opinions before I attempt a pretty major job.

Thanks everyone,

Greg

That’s an indication of a blown head gasket,

Tester

Yeah. You’re gonna be attempting a pretty major job. Do yourself a favor and get someone who knows their way around car repair to hold your hand for this one. Head gaskets aren’t the easiest repair job in the world for a novice.

You say compression numbers were consistent and in spec. What numbers?

Any of rhe spark plugs discolored. My experience is that coolant being consumed in a combustion chamber will have a tendency to bleach the plug and piston top a bit.

I’m not certain but I think coolant flows through the intake manifold on this one. What about the possibility of a coolant leak at the intake gasket or worst case: a flawed intake manifold.Just my 2 cents but I wouldn’t jump on the head gasket too quick.

How would that explain the coolant in the oil, though?

With the symptoms you listed you almost surely have a blown head gasket. The method you are trying to verify the gasket integrity is not exactly correct…its not that simple. The coolant bubbles from leaking cylinder compression into the cooling system…the pressures involved are far greater than your air compressor is able to reach…so it wont “present” with bubbles during your testing. You have plenty of blown head gasket symptoms so…proceed with the head gasket job.

The job is not really too difficult to perform on this vehicle and it will be an excellent learning platform for you.

You will obviously be removing the cylinder head… You can remove the head with the intake manifold and the exhaust manifold connected…and disassemble later.

Then…and this is important… Take the head to a machine shop to be “decked”…let them straight edge the component (they will use a very expensive machinist straight edge and also feeler gauges) you cannot use just some regular straight edge…they possess the proper item to measure these fragments of an inch of deflection / warpage. They will most likely need to cut the head to ensure it is perfectly straight which usually costs around $100…sometimes less.

Then and only then can you use new gaskets and reassemble the engine with confidence.

3 Likes

Thanks for the advice everyone.

ok4450 - the compression test results were consistent at around 180 psi for each cylinder which is in spec. The spark plugs all looked normal to me. No differences between them and they were the same shade of dark grey/black. Theoretically, would I find an issue with the intake manifold while I’m taking the engine apart, if that is the issue?

Honda_Blackbird - Thanks for the clarification. That makes a lot of sense why I didn’t see what I was expecting with my tests. I’ll ask you the same question, would I find an issue with the intake manifold while I’m taking the engine apart, if that was in fact is the issue? Also, I can’t rule out the possibility of the issue being a cracked head or block, correct?

Looking forward to taking the engine apart. I expect I’m going to learn a lot.

Thanks guys!