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thermostat housing leak

Mike's 89 GT

New Member
I swapped in a new 180 t-stat and now cant stop the housing from leaking. Stat is in the right way, new gasket and used black high temp rtv and still leaks. Anybody got any ideas as to different sealants,gaskets? Car is a 89 GT. Thanks
 

broncojunkie

Active Member
Is it possible the tstat slipped out of position before you tightened it down? I always use a little sticky stuff to help hold it in place. The yellow high-strength weatherstripping adhesive works great.
 

broncojunkie

Active Member
There's a few different things you can try. Inspect the housing and intake for cracks and make sure the housing gasket surface isn't warped. You can hold it flat against a piece of glass or other flat surface to check it. Look closely at the gasket surfaces for damage or pitting. If everything looks good, you can tackle it several ways. You can reinstall it using 2 gaskets. You can put a thin layer of rtv on both surfaces, let it dry, then install single gasket as normal. You can run a small bead of rtv and reinstall the t-stat and housing loosely. Wait 24 hrs, then tighten the bolts. If, after any of these methods, you still have a leak.... then there's either a hairline crack (probably around the bolt thread area on the intake) or a hose is leaking near the housing and it's being mistaken for a gasket leak. This would most likely be from the small bypass hose on the water pump.

I know leaks in this area can be frustrating! I've been through it a few times. Also, keep in mind that new t-stat housings are available, but they're notorious for being of poor quality. You can sometimes true them up with some heavy grit sandpaper on a hard flat surface but it's best to just get one from the parts store and inspect it well before you leave.
 

broncojunkie

Active Member
Also, you can buy a tube of "ultra black" or "The Right Stuff" rtv. That stuff is good, but keep in mind it's also harder to clean off.
 
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