ETA Head Gasket troubles?

[ForcedFirebird]

There isn't anywhere for the oil and coolant to mix on an m20, even with a blown HG. Only reason oil/coolant mixes in an m20 is a cracked head - which is EXTREMELY rare on an eta (they don't have #6 cam journal, and have thicker castings). If you study an m20 HG, the oil supply is right next to a head bolt, and the oil returns are all the way outside the cooling passages, and outside the block deck, even. If you had mixing from a blown gasket, the car probably wouldn't even run the head would have to be so warped.

BUT:

Let the car sit for a day or two, then pop the oil plug out. If there is indeed a significant amount of water/coolant it will come out first. Then plug it up when the oil starts flowing and take note of the amount of water/coolant.

If there's a slow leak into a chamber, a pressure test won't be easy to catch, but in turn a leak at there will also pressurize the expansion tank.

It is totally normal to have SOME moisture in your oil (ever notice the "cream" on the bottom of oil caps?). An engine is a "reverse" condensate. Just like a cold beer sweats on a hot day, the inside of the engine will condensate as it cools off, thereby adding a little water into the oil every time the car shuts down. Many people who take a lot of short trips almost NEVER let the car get to operating temps. That moisture in turn builds up in the oil - the vapor never gets burned off unless the oil temps reach operating. This is the main reason you are supposed to change oil every "3mos" or xxxx miles - oil breaks down when adding/boiling water in/out of it, even if the mileage is low.

[LateFan]

OK, thanks. This is all good to know. He's going to get a coolant pressure test and a leak-down test next. Could be the gasket, could be a crack in a passage I s'pose.

I'll ask him what the oil looked like when he drained it. The trick of replacing one head bolt at a time and torquing it down seems like a temporary band-aid to me. What we don't know is the quality of the work when it was done, whether it was skimmed flat, and what kind of gasket went on.

[e30davie]

Water has a specific gravity of 1, engine oil is about 0.82. So yep, oil sits on top of water, water will tend to sit on bottom of the sump. Does the dip stick sit on the bottom of the sump? i wouldn't think so. makes me think you have more water in there than you think.....

And yer, anything contaminating your oil isn't good for anything. Would not recommend.

[LateFan]

Is the biggest danger that you’ll contaminate the oil and quickly ruin bearings?

Oh - another question:
Is the coolant heavier and that’s why there’s a dab on the end of the dipstick? And would that mean it’s getting sucked up by the oil pickup at the bottom of the pan?

Thanks -

[cheffy30]

not a good sign by any means. change the oil. watch coolant levels carefully. document everything. mileage, amounts, etc. outside HG leaks are not as worrisome as internals. prepare for the worst. new head. sent from hell using Tapatalk

[e30davie]

I personally would be changing the oil and then monitoring the oil and coolant very closely as a good start. You can then also have a good look to see how much schmoo is in the sump. The schmoo on the end of the stick doesnt inspire confidence but you are only really going to know if you have an issue if you do a coolant system pressure test.

[LateFan]

1986 eta. Closing in on 200k miles. My son and I found this car about 7 years ago, have gone through most systems except engine internals. A couple of years before we got it, the PO's teenager let it overheat and cracked the head. A small town mechanic put a "good used" head on (we were told he pressure tested it) along with a water pump, timing belt, and radiator. No information on whether it was skimmed flat. He wouldn't have had access to the good quality head gaskets there - probably the local NAPA. It's been trouble free for us once we got it sorted. Drove it 1700 miles to his new town with no issues and the new manual we had just swapped in.

He's far away now, but reports some goo on the dipstick.
No white smoke.
Nothing showing in the coolant.
No overheating.
There has always been a right front oil seepage down the block from the head gasket.

I'm trying to help diagnose - is this a minor issue, and just keep fresh oil in it? Or the tip of the iceberg and we need to pull the head?
Is a leak-down test the first step? He's parking on the street with minimal tools there, so it would go to a shop to test.

A month ago before an oil change....


This week.....