vetteguy75

This weekend, I have had to replace the gasket on the thermostat housing 3 times!! The first time, I used the stock "paper" gasket. It leaked! The second time, I used the paper gasket with gasket sealant made especially for water pumps & thermostat housing....it leaked AGAIN! I even torqued the bolts to specs (20 lbs) and then some...30-40lbs. Still leaks... This last time I used Fel-Pro PermaDry Plus (a blue plastic gasket Part #35562T) with a thin coat of gasket sealent. No leak! BUT that was after idling 15-20 minutes with the heater on high...I did not get a chance to take the Vette for a spin to really test it out. It did get up to temp and all that... Now the question...as I was cleaning up afterwards and being HAPPY that finally the leak stopped, I noticed on the package of the Fel-Pro gasket it stated...."Important...Do Not use this gasket with any gasket sealent" I thought "OH Sh*t is it going to leak when I get up on the interstate????" Any help out there??? I hope I won't have to do this thing a fourth time!!!!!

74FLCONV

I'd run a straightedge along the mating surfaces of the manifold & housing.

I switched to an o-ring type t-stat housing and haven't had any problems.

D. Ocean
Miami, FLA

vetteguy75

Thanks! I forgot to mention....I sanded the both surfaces each time to make sure of a good contact.....

74FLCONV

But something still could be out-of-whack. It only takes a very slight bow to cause a leak, sealant be damned.

D. Ocean
Miami, FLA

z76232

I had the same thing happening to my 71. It was leaking around the t-housing so I cleaned everything up real nice and put a new gasket on it and it was still leaking. It's a chrome after market. I take it off again and really looked at it real close and saw inside where it had rusted and it was leaking through little rust holes in the housing. Went and got a new one for $10 and fixed it right up.
RDP

Ybnormal

Happened to me also, went a got me on of those purrrdy chrome jobs, put it on and it leaked, replaced gasket with sealer and it still leaked. Upon a close inspection of the housing before the third try I found a hairline crack in it, went and got another one and all was fine...

YBnormal...drive a vette

stingr69

Chrome water necks are just like chrome oil pans, they leak about 50% of the time.

I would not worry too much about the sealer. If it ain't leaking, don't fix it. Just my opinion.

-Mark.

vetteguy75

Thanks for all the input! Really appreciate it..... Just got back from a hard run....NO LEAKS! Between the Fel-pro gasket, the sealant AND the NEW chrome t-housing (another thing I forgot to mention), I think I got it....maybe with some over kill??

bobs77vet

i wonder if a faulty pressure valve that is not releasing pressure can cause increased pressure and therefore the antifreeze looks for away out???

vetteguy75

What is the pressure valve...the radiator cap?

Thanks

75 Hot One

If that material is the same as their rocker cover gasket, it's probably silicone and, although a sealer isn't necessary, it probably won't hurt. I've had good success with an O-ring water neck.

bobs77vet

yup, thats exactly what i mean.... instead of venting the pressure at the approriate PSI it does not vent and the whole radiator/cooling system gets over pressurized until something starts to leak....I would be curious to know at what temperature and for long before it starts to leak...as opposed to immediately after i turn it on...

killain

I have the same problem. Where can I get an O ring thermost housing with the O ring?

flood

The perma dry gaskets are made of neopreme (sp). I have one for my oil pan. They work really well.

A mechanic friend of mine says they are really good because its hard to over torque the gasket and they last a looong time.

bracketshark

I just bought a new thermostat housing this weekend for our super truck motor. Paid 9$ for it at Advance, we dispose of the chrome and aluminum housings and use the cast iron ones, they do not tend to bow like the softer metal ones but they will break if it gets in a bind and is overtorqued. Paint it your choice of color, install with gasket, and your leaks should be gone for good. This is just the fix we use but the o-ringed housing may work just as well.

vetteguy75

I had mine checked....it is releasing at 16 lbs....according to the manual that's perfect.

vetteguy75

Even though they are supposed to be installed dry...if you use gasket sealant stuff (made for water pumps & t-housing)...will it hurt it? I just don't want the sealant to start eroding the gasket......

cchristo

I use "The Right Stuff" http://www.permatex.com/right_stuff/right_stuff1.asp on just about everything. It's a little pricey, but it really seems to work. It comes in a little aerosol can with a nozzle. You just lay a bead down and it's almost immediately ready for use.