Hi everyone, I recently changed the thermostat in my firebird. I got a new gasket, but it was too small, so I went to the store to exchange it for the right size, the guy gave me the one they use for GM v6,v8 engines. It was very similiar to the original gasket, but alittle bigger. So I got creative and took a pair of scissors and cut around the edges so it would fit. Installed, 3 mins after car idling, coolant starts pouring out of the thermostat housing, withing a minute there was a nice puddle of coolant on the floor. So I removed it again and used some RTV silicon, tighttenned it....ran the engine, still coming out. BTW, its a paper gasket. Its funny how the store links my engine to a incorrect size gasket. Since its too big, or fits unevenly, can that cause it to leak? Any suggestions on what to do? Thanks.

 

did you clean the mating surface before you applied the RTV silicon and did you use the right silicon for the job?

 

I got two Questions.
1: Is the silicone heat proof?
2: Did you let it dry for about 5-6 hours before starting the car?

 

yeah, I cleaned the surface and i used RTV blue silicone, i think it said something about gasket maker on the tube. Im not sure if its heat proof, Ill check in a few minutes. I waited 24 hrs to start up the car.

 

I have the tube here, it doesnt mention anything about being heat proof. It says Sensor Safe Blue TV Silicone Gasket Maker. its this one http://www.permatex.com/products/aut...sket_Maker.htm

 

use the black stuff

 

I only use the LOCTITE RED silicone on my engine, it works great.
http://store.summitracing.com/egnsea...1&autoview=sku

EDIT: omg i just looked at the price on summit, that tube is about $14 over here.

 

haha....wow thats crazy, is the tube the same size? Today im going to go to the store and try to get that silicone, and probably a rubber gasket if they have them. Thanks for the help.

 

yeah same size coz i got a tube of it in my center console, that stuff is good for anything I use it for all my vacume, water and oil leaks you just need to clean the surface real well with a solvent first.

 

Summit Racing has at least 3 different thermostat housing gaskets, 1paper and 2 types of rubber. I use copper hi-temp rtv last 40 years, no problems with it.

 

I just applied it and Ill wait until tommorrow to start up the car. Ill post the results.

 

If it still leaks, check the housing and mounting area for cracks or pits. If it is aluminum and pitted, you may have an electrolisis problem that is easily solved.

 

ahh thanks, well if it helps, it never leaked before i changed the thermostat.

 

Two things you need to determine.

First, and most important, where is the fluid coming from? Not general area, specifically. I have been through this and to my surprise it wasn’t the work I had just completed it was something new. In my case the hose to the thermostat housing had debris inside it where the hose clamp tightened down, on the underside where I couldn’t see it. I thought it was the housing for at least a day.

Second, Look closely at the mating surfaces of the new thermostat gasket; you should see the witness lines where the gasket has mated. Trust me when I say the thermostat must compress the gasket in order to seal.

I got the same gasket you did, in a valve grind kit. I thought it was wrong, too big on the O.D. went the same path you did, and too small on the I.D, trimmed it up, leaked like a minnow bucket.

Long story short. Put a new gasket with the GM black RTV. You be fine.

 

Yup, I used the ultra black rtv thats heat proof. Im going to start up the engine later and post back the results.

 

Good news! No leaks!! I let the engine run until the thermostat openned. Thanks alot guys! All I need now is to get that fan to kick on and Im all set.

 

HAHAHA damn thing is leaking again. It sure looks like its coming from the housing, but its hard to tell. I will try and post a pic soon.

 

Look very carefully around the bolt holes, the aluminum housing can crack from overtightening and the crack is quite small. I bought a steel one from Napa painted it silver and never had the problem again. I cracked two of the aluminum ones over the last two years. Mongo like to tighten his bolts good.

 

When you remove the housing, check it for nicks or gouges. Pay attention to the bolts and see if they loosened up and caused the leak. I changed from bolts to studs and they seem to stay tighter over time.

 

Alright guys, new update. I finally had some time to fight this. I removed the thermostat housing and i noticed a lot of pits on the surface and it looks a bit warped. So I ordered a new one, and should be here by the end of the week. I also orded 2 different gaskets for it, just in case one doesnt fit well.

My question now is, should I apply the black rtv to both sides of the gasket, or just one side? Thanks

 

I usually use high tack on the new part (for positioning), and a thin bead on the old, but either way works, just don't use a ton

 

Mabey i am dumb but that thermostat should have 2 gaskets and i havent read anything about it on above post, the rubber o-ring type goes in between the thermostat and the intake, then i would use rtv between the hose neck and the intake 1/8 bead let it set 5-10 min before bolting down the hose neck, or you could use the paper gasket there. But with out that o-ring type gasket its gonna leak.

 

O-ring? I havent read about that anywhere, are you sure I have to use a O ring and a gasket?

 

http://www.autozone.com/R,APP749301/...ductDetail.htm


I looked up your car on autozone to be sure. The part # is 35666

 

This isnt your intake but the arrow points to the groove where the gasket(o-ring)goes.

 

hey I had the same problem I blew the paper gasket. Auto zone has a thermostat gasket that looks like a spacer. You dont have to use the o ring or any gasket sealer. its $14.99 but that thing is awesome. all you do is bolt it on and go. no drying or leaks at all. the gasket part is allmost like polyeurethane. and it has a metal outer gasket spacer like deal. that is the best part I have seen for the price.

 

Cool. My local autozone doesnt have any cool **** like that lol. I got my new thermostat housing and gasket. Now Im trying to decide whether or not to install it tonite, or wait until saturday and get a O ring at my local parts store....decisions...

 

http://www.mr-gasket.com/pdf/gaskets.pdf go to page 140 (12 of 52) in the gasket section diagram 738G. This is what I bought at autozone. when you get on the site just scroll down till you see a therm gasket.

 

Cool. Is this good for my 2.8 v6? I found it at the autzone site. http://www.autozone.com/R,APP739831/...ductDetail.htm

 

yes that is the part I have for my car. It is the best your money can buy. that is the exact same one. you dont have to use the o ring for this either.

 

But my motor is a v6. Will it fit?