Damn leaky thermostat housing - 1990 5.0

[BLAKE]

This thing is just made to leak. I'm on my 3rd new gasket in 6 months, and I still get a little pool of coolant on the timing cover on the driver's side. It's on an Edelbrock Performer RPM intake if that matters.

Any tips or tricks you can give me to make sure this thing keeps the green stuff in?

[Baba Ganoush]

I’ve chased that before. What worked for me was taking some 2000 grit sand paper and a block/straightedge and leveled out the mating surfaces. Then I use RTV with the gasket and let it set up before install, like longer than you’d think, 15 min or so before I installed it. Then let it sit and cure overnight before adding coolant and running it to temp.

[Rick Modena]

I did the same on my '89 5.0, except I used 180 grit to smooth and take off any left over gasket material on both sides. I then used ATV black on both sides and let it set up overnight as well. It never leaked again, well as long i owned it.

[BLAKE]

Dang, you guys describing pretty much exactly how I did it. I think I used 320ish grit.

[Rick Modena]

Dang, you guys describing pretty much exactly how I did it. I think I used 320ish grit.

That grit should be OK, I had rust and leftover gasket material, so I used a metal work block and 180, but any type grit should be ok. Getting that surface cleaned and free of any gasket material or old sealant is the key to making it leak free. That is unless you have a warped thermo housing and then it will leak like a sib until it is replaced.

[Baba Ganoush]

I also only snug it and come back an hour or so later to tighten it. Let it cure, that’s the key. Also thread sealer on the bolts.

[bird_dog0347]

Le Sigh.... same. I guess I need to do that as well.

[talisman]

Those housings are more annoying than the top starter bolt when you don't have five or six extensions.

[bubbaearl]

after running tie a shop towel around the hose . many times the hose will seep as pressure builds after shut down .

[BLAKE]

Thanks for the feedback y'all. I'll keep playing with it.