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| | | | Joined: Feb 2002 Posts: 2,893 Socket Breaker | | Socket Breaker Joined: Feb 2002 Posts: 2,893 | 1965 Chevrolet C10
1992 Chevy truck engine, 350/5.7L(v8)
I run the engine, can not see any spewing coolant, no leaks.
I park it. Check it the next day or the one after... suddenly there is coolant on top of the intake manifold, around the thermostat housing/water neck.
So, my first thought is loose hose clamp or not adjusted right on the water neck. Checked that. Gasket for the thermostat housing was replaced in November 2023... maybe it isn't snug enough?
This is making me cuckoo. Anything else I can check?
It only leaks after it sits, never while it is running... or at least not while I am looking at it while it is running.
Thanks.
-Woog | | | | | Joined: Feb 2004 Posts: 29,832 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,832 | Do you have access to a cooling system pressure tester? I'd suggest pumping the system up to within a pound or two below the pressure rating of the radiator cap (probably 13-14 pounds) with the engine warmed up to operating temp and then shut off, and look for seep leaks as it cools down. I've cured small leaks like that by draw-filing the gasket surface of the thermostat housing on occasion. It might be warped slightly so the gasket isn't sealing equally across the whole surface.
Jerry
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| | | | | Joined: Feb 2016 Posts: 1,990 'Bolter | | 'Bolter Joined: Feb 2016 Posts: 1,990 | I agree with HRL, the thermostat housing is a soft alloy, they deform kinda' easy with heat, age, torque. Remove the housing and file the surface flat. If it is an aftermarket housing with an O-ring, I had poor luck with that style. Make sure the bolts are not too long, are they bottoming before the housing is snug? Also, look at the heater hose connection if there is one in the intake manifold, should be close to the t-stat.
1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy
| | | | | Joined: Dec 2020 Posts: 1,966 'Bolter | | 'Bolter Joined: Dec 2020 Posts: 1,966 | Put your finger there and wet find the wet spot. Either at the hose or the housing.
My housing with the O ring leaked at the base. It was hard to get it fixed after the engine sat.
I used sealant
~ BD.
"You won't find me in an old folks home" Pioneer Florida Cracker
1958 Apache Stepside
1958 Apache 1/2 ton Panel
1959 Apache 1/2 ton Panel
| | | | | Joined: Mar 2004 Posts: 6,214 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 6,214 | I had a chrome plated T-stat housing on my V8 sbc corrode and leak from under the chrome. I was amazed how the inside was all eaten up... Mike B  | | | | | Joined: Feb 2002 Posts: 2,893 Socket Breaker | | Socket Breaker Joined: Feb 2002 Posts: 2,893 | Thanks for the replies folks.
-Woog | | |
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