Coolant leak

[Wigert]

Hello everyone! I am new to the registry and own a 1990 zr1. I have several issues that need solving including a coolant leak, an oil leak and a very high oil consumption. But lets start with the coolant leak and i will start new threads on the other stuff when i get to those...

The coolant leak seems till be coming from the lowest part of the thermostat housing. I hope it is visible in the picture. I could not really see any coolant running from further up (even though it seems wet). I looked in the factory manual and there does not seem to be a seal in the housing? The bolt seems tight. Any suggestions om what to do would be much appreciated.7123

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[Dynomite]

http://www.jerrysgaskets.com/seal-coolant-thermostat-90-95-11c1/

Thete are some tricks in removing thermostat.

Thermostats, Fans, Water Pump, and Radiators (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp.html#post1580070558)

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[A26B]

There is a seal around the thermostat flange, inside of the housing.

The lowest part of the thermostat housing is where the leak end up, but may be higher up. You will need to clean the housing & connections, then dry off.

There are 2 heater hose connections on top of the housing that could be leaking, as well as the hose clamp visible in your photo (Have you tried tightening the clamp?).

Once dry, you can try to wrap a narrow band of folded paper towel around the heater hose connections. If they become wet, then you know the leak is in that area.

Once you locate the leak, better help can be provided.

[Wigert]

Hey Dynomite!
Thanks for the reply. I did not realize that the seal that you referenced was also a seal for the housing. I thought that there would be an additional seal just between the mating surfaces. So replacing that seal should help with the leak? It does not seem to complicated to replace it.

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[Dynomite]

Hey Dynomite!
Thanks for the reply. I did not realize that the seal that you referenced was also a seal for the housing. I thought that there would be an additional seal just between the mating surfaces. So replacing that seal should help with the leak? It does not seem to complicated to replace it.

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The complicated part is keeping the seal in place as you put the two thermostat housing halves back together as the thermostat wants to spring out just a bit. That is where the putty knife comes into play :p

[Wigert]

Thanks for the additional input A26B! The hose connected to the radiator seems also to be leaking slightly. I have already done the paper towel test and there was not so much coolant on the paper even though plenty of drops from the bottom of the housing. I will by some hoses from Jerry's gaskets as well.

I also tried tightening the clamp without success...

[RussMcB]

Call your local auto parts stores (chain) and borrow a Stant Cooling System Pressure Tester. It will show you exactly where your leak is. No guessing.

[Wigert]

Call your local auto parts stores (chain) and borrow a Stant Cooling System Pressure Tester. It will show you exactly where your leak is. No guessing.Thanks for the tip! I will see if the local show has one of those.

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[Ccmano]

Call your local auto parts stores (chain) and borrow a Stant Cooling System Pressure Tester. It will show you exactly where your leak is. No guessing.

Good idea, but not sure they do that in Sweden.
H
:cheers:

[RussMcB]

Good idea, but not sure they do that in Sweden.
H
:cheers:(forgive me if I've posted this before - I probably have...) I bought mine 20 years ago for < $100 and it has been a great investment. I use it often, and often lend it out. Sometimes you need to buy an adapter if your radiator cap isn't "regular ole American" (like my Miata). On my race car, whenever I've done stuff with the cooling system, I check if it holds pressure, It always tells me if something's not tight. It's great to find problems in the garage rather than away from home.

[Wigert]

(forgive me if I've posted this before - I probably have...) I bought mine 20 years ago for < $100 and it has been a great investment. I use it often, and often lend it out. Sometimes you need to buy an adapter if your radiator cap isn't "regular ole American" (like my Miata). On my race car, whenever I've done stuff with the cooling system, I check if it holds pressure, It always tells me if something's not tight. It's great to find problems in the garage rather than away from home.Thats also a good idea, I will have to google it and see if I can find a good source.

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[Wigert]

I just wanted to close up on this thread. After replacing the thermostat and some of the cooling lines with parts from Jerry's the coolant leaking has ended. I want to thank you all here for the support. The putty knife tip was very useful I might add.

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