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Small leak from thermostat gasket (permatex). What quality part should I buy? Would you replace just the gasket or housing or housing and thermostat?

tonyp25

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Looks like the guy before me used a blue adhesive silicone gasket maker. There is a small leak (circled in yellow below) coming from the blue gasket. From reading other posts a lot of people seem to recommend either Mancini or billet or just replacing the gasket with one from realgaskets.com. I might be overthinking this but just want to get it right the first time.

I was about to just go with a housing (motorad) and gasket (felpro) from rock auto but not sure that’s the best choice. Thermostat seems to be working perfectly so not really sure I need to replace that. Cost isn’t an issue. Plus the current thermostat housing has two different bolts in it and is surely not torqued to spec.

What do you all recommend? It’s for a 1974 Road Runner, 318. When I search on jegs or summit, not many housings come up when filtering for ones that fit my car and the ones that do are all dorman brand

Also noticed my temp sending unit is disconnected with only a taped up wire next to it. Can I wrap that wire around the sending unit or is there a plug that should be attached to it?

IMG_6337.jpeg
 
The best answer is the Felpro with Permatex grey water housing sealant. Just be aware it has a 24 hr dwell time for refill. Also, check the housing to thermostat fit. I had a leaker and it was one of the chrome necks poorly machined. It did not cover the depth of the thermostat. Autozone actually had the entire kit in stock although I used a high flow thermostat instead.
Notice the old housing was not flat one, and too shallow to cover the thermostat.

IMG_4204.jpeg
 
The best answer is the Felpro with Permatex grey water housing sealant. Just be aware it has a 24 hr dwell time for refill. Also, check the housing to thermostat fit. I had a leaker and it was one of the chrome necks poorly machined. It did not cover the depth of the thermostat. Autozone actually had the entire kit in stock although I used a high flow thermostat instead.
Notice the old housing was not flat one, and too shallow to cover the thermostat.

View attachment 1496053
As above, make sure the housing is flat. I recall having issues years ago with warped thermostat housings on 318 and 360's.
 
The best answer is the Felpro with Permatex grey water housing sealant. Just be aware it has a 24 hr dwell time for refill. Also, check the housing to thermostat fit. I had a leaker and it was one of the chrome necks poorly machined. It did not cover the depth of the thermostat. Autozone actually had the entire kit in stock although I used a high flow thermostat instead.
Notice the old housing was not flat one, and too shallow to cover the thermostat.

View attachment 1496053
Any recommendation on thermostat housing brand? Or should I try the one I have with the felpro gasket and adhesive first as long as the housing seems solid?

I’d like to replace the mismatched bolts and figure out what they need to be torqued to
 
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I'm a huge fan of the Real Gasket 53063. Don't have to wait for silicone to cure, no cleanup required when swapping stats, reusable, and they seal.
 
Any recommendation on thermostat housing brand? Or should I try the one I have with the felpro gasket and adhesive first as long as the housing seems solid?

I’d like to replace the mismatched bolts and figure out what they need to be torqued to
Do not get any chrome
 
Check out "Terry's Auto Lab" if price is no object. I purchased 2 of them at one time when they were cheaper but, they are nice and leak free.
Mike
 
I use Permatex Ultra Black or Gray. However it's probably leaking because one of the surfaces isn't flat. I would get a block of wood and some 120 grit sand paper and go over both

surfaces. The gasket should seal by it's self without the need for sealer.

Tom
 
Skip all silicone and use Indian head shellac watch your problems go away
This is THE ANSWER. Awesome for coolant leaks. Cannot be overstated, it works! Follow the directions!

gasket shellac compound by permatex. In a small brown bottle with a round applicator ball attached to the lid. Could say Indian head but the libs ousted that name

Silicone isnt good on a coolant gasket IMO. I use ultra black on everything else but coolant.

blue silicone is garbage. I once bought a used car, every leak on it had that blue stuff Involved.

B1E76E69-36D5-450A-A829-0457E45AD981.png
 
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I had the same issue once. As stated above don't buy chrome housings unless you're a gambler. After tossing the new leaky chrome housing, I had my original leaking housing plained at a machine shop. It only needed a little shave and it's still leak free many years later.
 
I bought a Mr. Gasket machined aluminum housing and no leaks in 10 years. Most of the originals and the pretty chrome ones warp and no amount of silicon will ever stop it. It was probably about $25 back then and definitely worth it. It is on a gen 2 hemi and runs pretty warm in the summer. Nothing was used to seal it just a good felpro gasket.
 
Skip all silicone and use Indian head shellac watch your problems go away

This is THE ANSWER. Awesome for coolant leaks. Cannot be overstated, it works! Follow the directions!

gasket shellac compound by permatex. In a small brown bottle with a round applicator ball attached to the lid. Could say Indian head but the libs ousted that name

Silicone isnt good on a coolant gasket IMO. I use ultra black on everything else but coolant.

blue silicone is garbage. I once bought a used car, every leak on it had that blue stuff Involved.

View attachment 1496102
Been using this for over 50+ years. Ask me how many leaks I've had on customers, or my cars. Of course, ensuring the surfaces are FLAT and TRUE is a prerequisite.
 
They're garbage, lucky if you get one that doesn't leak.
yUP. IT'S NOT THE CHROME IT'S THAT THOSE ARE DIE CAST FROM cHINA AND ****. I have had a small leak on mine, and it is chrome. I wanted a cast iron original type but couldn't find any repops just used so I bought a CNC aluminum from Mancini. I went with Mancini because others didn't supply the gasket, they did
 
Just toss a big block in there and you wont have to worry about a leaky intake anymore:lol:
 
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