Thermostat won't seal!!

Na5.0HO said:

Ok, so I just got a new intake (used Edelbrock) and I had to put my old thermostat housing on it. Well when it was off the car my buddy did the swap and didn't use a gasket or sealant.

Neways, I've put in a gasket and it leaks from the bottom.. I figured it was becuase I couldn't get the surface dry on account of the intake still being on hte car. I tried draining the coolant first, completely drying and using a gasket w/ sealant... it leaked.

Ne ideas why this stupid thing won't seal!?!

Thanx if anyone has any advice... I just needed to vent and give it a shot

Click to expand...

The trick is to get both surfaces clean and flat. Make sure all old gasket material is removed

TRY THIS IT WORKS EVERYTIME FORE ME

Put some gasket maker on the housing where the t-stat goes on
Put the T-stat in there pointing in the proper directing

Next lightly spread some more gasket maker where the paper gasket will seat on the housing

Install gasket on housing

Let sit for about five minutes

Now install the assembly onto the lower intake manifold

Tighten both bolts evenly and if possible use new lock washer on those bolts.

DO NOT OVER TIGHTEN!

what i like to do:
take the housing off.
use a turkey baster, etc to get as much liquid out of the lower intake as i can. then use paper towels to dry it real well.
use a new gasket and i use waterpump and t-stat housing gasket sealant on both sides of the gasket.
then toss it on.
make sure the t-stat stays where it needs to be (doesnt slide down) while you install the housing.

the other possibility is that the mating surface is warped. with the intake in, a machinist's straight edge may be your best bet to check for plumb. do the same on your housing.
all i got, good luck.

Usually the problem is that the t'stat slides down during installation partially blocking the sealing surfaces at the bottom. Pay a bit more for the proper gasket -- it has a peak 'n stick adhesive on one side. Peal it, and with everything clean and dry, put the t'stat in the t'stat housing indention; then stick the adhesive side of the gasket to the t'stat housing. The adhesive will not only seal, it will hold the t'stat in the t'stat housing indention so it won't slide down. Simply bolt it in place. I usually use paper gasket dressing (Permatex Hylomar) on the non-adhesive side of the gasket -- I've never had one leak. The proper parts and tools make all the difference.