394 coolant leak

Old May 14th, 2018, 06:42 AM
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394 coolant leak

My 61 Starfire leaks coolant which accumulates on the valley cover beneath the intake manifold. It's not leaking around the thermostat housing or the hose connections or the heater control valve. I assume there's leakage at the gaskets where the intake bolts to the cylinder heads. There are no signs of head gasket problems, compression is normal, no combustion gases in the coolant, it runs fine. Are there any other possibilities before I pull the intake manifold? Any thoughts on the best source for replacement gaskets?
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Old May 14th, 2018, 11:09 AM
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A small mirror and a flashlight may help you spot exactly where the leak is .
The most likely suspect will be the "water " ports at the front of the intake .
Before replacing the gasket make sure that the surfaces are clean and flat . Check them with a straightedge and a .002 feeler guage , if possible .
Fel-Pro gaskets are a good choice . Usually available on order from O'Reilly's etc. or E-Bay.

Last edited by Charlie Jones; May 14th, 2018 at 11:16 AM.
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Old May 14th, 2018, 12:53 PM
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Thanks for your help.
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Old May 14th, 2018, 04:41 PM
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Since you have a '61 Starfire , why don't you come and join the "Darksiders" at this thread;
https://classicoldsmobile.com/forums...ers-unite.html
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Old May 14th, 2018, 08:26 PM
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Originally Posted by highleymd View Post
My 61 Starfire leaks coolant which accumulates on the valley cover beneath the intake manifold. It's not leaking around the thermostat housing or the hose connections or the heater control valve. I assume there's leakage at the gaskets where the intake bolts to the cylinder heads. There are no signs of head gasket problems, compression is normal, no combustion gases in the coolant, it runs fine. Are there any other possibilities before I pull the intake manifold? Any thoughts on the best source for replacement gaskets?


Like Charlie says get a small mirror and look under your connections onto the heater control Valve at the rear passenger side. They are notorious for leaks where they bolt to the Block and where the Valve tightens into the mounting bracket. When it leaks it will be difficult to detect but the coolant will lay under the intake manifold on the Valley Pan. Sometimes the Vacuum diaphragm will weep as well.
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Old May 15th, 2018, 06:29 AM
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You can rent a coolant system pressure tester at most any Napa or AutoZone Etc. Pressurize the coolant system with the car off and look for your leaks with it not running. You can also put dye in the system so you can see the leak easier or use a blacklight.
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