Coolant on intake manifold
Thread Starter
Heel & Toe
Joined: Oct 2011
Posts: 21
Likes: 0
Coolant on intake manifold
74 350, coolant is pooling around the first intake manifold bolt on passenger side. it is an Edelbrock Performance intake manifold.
Oil is fine and coolant in radiator is nice and clean. Fairly certain it is not coming from thermostat housing or heater hose. Can coolant just push out thru one bolt like this or does it mean entire intake manifold gasket is no good? I have read that removing the one bolt and using permatex on the threads and reinstalling it may solve it? Do not want a coolant leak into manifold, but if this is just isolated to one bolt that would be the easier option. Thanks
Oil is fine and coolant in radiator is nice and clean. Fairly certain it is not coming from thermostat housing or heater hose. Can coolant just push out thru one bolt like this or does it mean entire intake manifold gasket is no good? I have read that removing the one bolt and using permatex on the threads and reinstalling it may solve it? Do not want a coolant leak into manifold, but if this is just isolated to one bolt that would be the easier option. Thanks
Team Owner
Joined: May 2001
Posts: 87,380
Likes: 1,593
From: Western NY
FelPro makes a special gasket for the t'stat housing that is "the nuts". It's a piece of plastic, about 3/16" thick, with a rubber "quad ring" bonded to the ID. I've used several over the years, and NEVER had a leak issue afterward.
Melting Slicks
Joined: Mar 2008
Posts: 2,023
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From: Austin Tx
Melting Slicks
Joined: Jul 2009
Posts: 3,264
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From: Vero Beach FL
Drifting
Joined: Jan 2002
Posts: 1,645
Likes: 11
From: Schaumburg IL
Yep, t-stat gasket and bolts, intake manifold bolts and a place to ck is the heater hose fitting into the intake manifold. Under pressure it can leak. Wipe off all coolant from the intake and run the engine till fully warm and under pressure. Look for leaks. Turn it off and it will stay pressurized for quite a time. Ck back as it cools and see where the wet seems to be from. Sealing with permatex on all bolts works. I use Avation form a gasket on the t-stat housing gasket both on the gasket and metal sides. Let set for overnight and it works.
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Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
I removed that intake bolt on a 1979 L-82 last summer. It had narrowed down in the middle from corrosion just like an exhaust manifold stud. It was remarkable that it came out without snapping. Invest in a new bolt and some Permatex.
Team Owner
Joined: Jul 2004
Posts: 40,412
Likes: 792
From: Redondo Beach, California
You can see corrosion with older manifolds..bolt holes..mating surfaces for gaskets. I have none of these problems. I've have no water in the coolant system of 68 since about 1973. Only pure 100% ethylene glycol (aka green stuff). I still have the factory heater core. I use 100% ethylene glycol in my 97 Thunderbird DD and my 95 Cadillac Seville DD. When you get the water out of your cooling system, you'll never have a corrosion problem again. Also, with 100% ethylene glycol, the cooling system never pressurizes. This minimizes leaking problems and you can remove the radiator cap any time you want, no matter how hot the engine is. ...Pure ethylene glycol has a problem if the temp gets really cold..it turns to the consistency of honey...or if cold enough rock candy. If it freezes hard (probably an unworldly low temp) it won't crack your block since it contracts when freezing. No problem here in So Cal.
Thread Starter
Heel & Toe
Joined: Oct 2011
Posts: 21
Likes: 0
The cause
Thanks to all who replied. The leak was actually from the thermostat cover/water outlet housing. The bolts were barely tight, surprised it did not leak worse, no real gasket in there, just a skim of gasket cement or permatex. While I had it off replaced the water outlet, was starting to corrode near where the dome meets the base. Used that Fel-Pro thicker gasket you recommended, very nice.