ChuckD

I can see coolant pooled behind the fuel pressure regulator and t-stat housing. Is this a standard place for a coolant leak and what is most likely culprit? T-stat housing or maybe the heater hose (assuming that's what it is that leaves that area and heads over to the expansion tank)? Any thoughts? Thanks!!!

the flyin' scotsman

whats the year and model of 928?

Mrmerlin

if the leak is at the front of the engine by the water bridge then yit can be leaking from these areas
the heads to waterbridge gasket,
the bridge to block O ring not very common,
the Thermostat O ring.
Any one of the 3 hoses attached to the water bridge,
either a loose clamp or the hose has been damaged internally ,
Remove the 3 hoses,
and inspect them for damage from the little pins that come out of the tops of the metal outlets on the connections.

If the leak is at the rear of the engine by the HCV then you should replace the HCV and the short hose,
inspect the block off plate and water outlet at the rear of each head for the bolts and or gasket being loose or leaking,
the metal tube that the short hose is connect to can also work its way out of the housing on the RR head, JB weld it back in place

Dave928S

I just finished looking at mine and was about to post ... but Stan has said it all.

What helps in diagnosis is to let it cool down, de-pressurise the system, mop up coolant, dry everything by blowing out with compressed air, then start it up and watch as the system builds pressure when it warms up. Have an inspection mirror and good torch ready to check all those areas Stan mentioned.

jorj7

Let's hope he doesn't have a fuel leak when he lights his torch...

I know, English to American translation issue.

928 at last

Yes, but somehow rallying the villagers to storm the castle with flashlights doesn't cut it either..... (Even Maglites)

ROG100

Rob - Classic!!!

ChuckD

It's definitely up front. I am new to this engine. 1982 automatic. I see a few hoses at the "bridge" and I am sure it's one of those. I was going to start another thread asking what the usual time is for the car to warm up. I have the high idle issue and need to really go through it. Vac lines are all horrible looking and disintegrating. I drove the car a few miles the other day to get it to my house and the water temp needle never came off the peg, so it either doesn't have a good connection in gauge pod or the temp sender is bad (or whatever). Hell, I don't even know how to tell if the fan is working correctly. I had asked about it a few months back and didn't really get a good answer. It spins all the time. How would I know that the fan is operating correctly? Should it spin when first started or what. if it is a viscous thing, wouldn't it not spin until it gets hot? Sorry for the stupid questions. I do appreciate the help. I finally have the car in my garage and love to just stare at it. I've always wanted one.

WallyP

The fan always spins. The viscous coupling lets it spin more slowly when cold, and faster when hot - if it is working correctly. The best test is to have the engine hot, and with the hood open, rev the engine and hold it at about 2500 RPM for thirty seconds. After the first few seconds, the air being moved and the noise level should both increase.

It sounds as if the thermostat might be stuck open.

the flyin' scotsman

excellent Rob......gotta love the collonials

The water bridge and t.stat have several gaskets and Orings and with the car being 30 yo it might be time to consider replacing all, inspect all hoses and renew the coolant......good for another 30 years.

ChuckD

Tanks Wally! That makes sense...change in speed. I hope it's as simple as the t-stat stuck open, although I can tell I will be chasing things all over this car. The water temp sender is pretty nasty and corroded looking too. Just going to have to go through it. I bought the big rad hoses because they are soft and plan to go through it. Just looking for insight before I open it up.

James Bailey

Be aware that you can not run it very long without a thermostat . The small hoses heater hoses etc all see the same pressure as the two big ones but are seldom replaced until they fail.

ChuckD

I ordered up anything that might leak in that area except the smaller hoses from Roger today. What a great resource. I have the bigger rad hoses already and coolant system is my first step in going through this engine. Thanks to all.