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Re: Case of the missing coolant

Posted: Fri Jan 02, 2026 1:38 pm
by BennSport
Well I just checked my coolant reservoir to find a creamy brown color, and pulling my dipstick I saw little bits of coolant on it :?

Re: Case of the missing coolant

Posted: Fri Jan 02, 2026 2:10 pm
by Tom
Poorsche44 wrote: Fri Jan 02, 2026 1:38 pm Well I just checked my coolant reservoir to find a creamy brown color, and pulling my dipstick I saw little bits of coolant on it :?
Well, that's a bummer. :cry: :cry: Often hard to tell if it's the oil cooler or the head gasket. Any other symptoms? Any coolant overflow? Try pulling the spark plugs and looking for any signs one or more have been steam-cleaned (by a leaky HG). A lot of people just do both...

Re: Case of the missing coolant

Posted: Fri Jan 02, 2026 2:55 pm
by BennSport
Definitely no coolant overflow, if anything the opposite. I’m assuming that would mean it’s head gasket failure?

Re: Case of the missing coolant

Posted: Fri Jan 02, 2026 4:06 pm
by Tom
Poorsche44 wrote: Fri Jan 02, 2026 2:55 pm Definitely no coolant overflow, if anything the opposite. I’m assuming that would mean it’s head gasket failure?
Coolant spitting out the overflow after a hard drive is often a sign the head gasket is blown. Combustion pressure leaks past the fire ring, pressurizes the coolant, and the overflow acts as a release valve. The lack of that is one clue in favor of this being the oil cooler seals. Another clue in that direction is oil in the reservoir, which is also more likely to be the oils seals. Check your spark plugs and look for coolant in any cylinder -- either of which could be a strong indicator of a bad head gasket. They also make those kits that check for exhaust gas in the coolant. I've never had much luck with those kits, but it might be worth a try. Other HG symptoms: compression test might reveal a bad HG too; history of overheating; white steam out tailpipe; sudsy/bubbly coolant in reservoir after driving; rough idle that smooths out after warm-up? I'd lean toward seals based on the oil in the reservoir, but would want to collect more clues before digging in -- unless you decide to just do them both.

Re: Case of the missing coolant

Posted: Fri Jan 02, 2026 4:15 pm
by BennSport
I have found my car to run fairly warm, with the fans engaging often, but not overheating to dangerous levels frequently. Would the oil cooler seals be easier to get to rather than the head gasket?

Re: Case of the missing coolant

Posted: Fri Jan 02, 2026 4:19 pm
by Tom
Poorsche44 wrote: Fri Jan 02, 2026 4:15 pm I have found my car to run fairly warm, with the fans engaging often, but not overheating to dangerous levels frequently. Would the oil cooler seals be easier to get to rather than the head gasket?
Yes, oil cooler seals are easier -- still a messy pain, but pulling the intake, cam belt, cam, head, etc. is more work for sure. On the other hand, with the head removed, replacing the oil seals is never going to be easier, which is why some people will do them both at once..

Re: Case of the missing coolant

Posted: Fri Jan 02, 2026 8:06 pm
by BennSport
Hmmm, I think I will replace both at the same time. Are there any specialty tools or anything similar that I will need beforehand? Also curious as to which guide to follow for my model year

Re: Case of the missing coolant

Posted: Sat Jan 03, 2026 10:38 am
by 951tom
Vent screw torque is 9-11 ft. lbs. per the tech spec manual. I'd definitely do some more testing before tearing into a head gasket. I agree with Tom most likely the oil cooler seals.

Tom
'87 951

Re: Case of the missing coolant

Posted: Sat Jan 03, 2026 12:17 pm
by BennSport
How would I do a compression test considering I don’t want to run the engine with the mixed fluids?

Re: Case of the missing coolant

Posted: Sat Jan 03, 2026 3:42 pm
by BennSport
After pulling the spark plugs I didn’t see any coolant in the cylinder, although with no borescope it was pretty hard to look. However, the plug on cylinder 2 had some white buildup on it. Would this mean I have a head gasket failure at the front of the block?