924Board.org

[mvde27]

Backstory and evidence.

Coolant leak up front. Changed the top elbow and water hose down below. No leaks now up front. Now that the entire front is all sealed up, pressure has now increased in the back of the engine, coolant is leaking and cannot identify where.

Research indicates under the solenoid area as the coolant is dripping in that area on the starter down below. I can see coolant down in there but not the source.

I was going to top off coolant. Jack up the car and run it to hot and then get under the car and Sherlock Holmes the girl.

Any additional insight is greatly appreciated. Just missed to beautiful fall days of driving!!!
_________________
'82 931

[barnwerks]

Buy or borrow or rent a coolant pressure tester to diagnose any remaining leaks.

[mvde27]

Thanks.

Pump the pressure up to or just below 1 bar 14.5psi.
Is that on a cold engine?
What is the wait time typically for the leak to show?

Cheers.
_________________
'82 931

[chuck21401]

Autozone has free tool rentals with a deposit.
https://www.autozone.com/test-scan-and-specialty-tools/loaner-radiator-pressure-tester


The leak could be coming from anywhere of course but I'll share my experience with a leak at the back of my 924 turbo.

In my case I had loosened a bolt to remove the boost control line that runs from the boost pipe to the wastegate.

It turns out that bolt holds a flange for the cooling system to the back of the head. Took me a while to figure out what was going on....I tightened the bolt (but not too tight!) and the leak stopped.

The parts diagrams can be helpful or at least offer some clues.

Here's the cooling system diagram to give you an idea of what's back there including a couple of sensors and switches...not to mention hoses and various hard lines. Maybe you'll get lucky and find that something is loose.



The flange is (2) in the diagram below; I removed one of the bolts (5) and soon found that the engine was leaking coolant.


_________________
1981 Porsche 931 w/S1 engine & euro g31 transaxle. Water-cooled intercooler

[mvde27]

Thank you for the response.

Here is the latest.
Was able to acquire a Coolant Tester.
Topped off the coolant between the min max line.
Cold Engine to test
Pressure test, pumping up to 1 bar
Did initially hear a hissing sound coming from the middle of the block but then faded before I could identify.
Left the car under pressure as I crawled underneath where the previous leak was and nothing.
Went back up to the top to see if there as any new coolant that I could identify and nothing again.

Took the next step of taking one of the plugs out to see if the dreaded coolant was in the block and all good there as well, however I only checked one plug.

@chuck21401 I did go through all of the hose clamps and made sure that they were all snug. I did discover that the back of the engine is a mess and not at all like the PET. the PO must have made some hoses and short cuts so I think that might be the cause? Although none of those hoses were wet or show any signs of pink dried coolant.

The flange that you identified is there but the connection is completely different so I am going to go back there and make sure that it is all correct.

Other than that, taking the car for a spin tomorrow and getting up to temp and coming back and jacking it up is my next attempt to find the source.

Thanks again.
_________________
'82 931