2V thermostat replacement

96gtINP

New Member
Aug 5, 2005
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Has anyone ever changed out the thermostat in their 4.6 2V? The O-ring seal in mine is driving me insane I can't get it to stop leaking. I checked the intake manifold and I don't see any cracks and the leaking seems to be coming from the seam between the upper thermo housing and the intake. Any help someone could give would be appreciated.
 
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The thermostat is at the end of your top radiator hose, after draining some coolant out, disconnect the hose, and the housing at the end of the hose, take out the thermostat O-ring, and use gasketmaker to reseal the t-stat housing or you will get an annoying leak. While you are draining coolant, now would be a good time to clean you engine coolant system, especially sense the temps got hotter.:flag::nice:
 
I've had two elbows where the thermostat goes (PI intake, and on the blower), and have never had to put any gasket maker to keep it from leaking. O ring could be bad. New thermostat only costs like $9.

Are you sure the thermostat housing itself isn't leaking? When my old NPI manifold went bad, that's where it leaked at, and I couldn't see any cracks in it either.
 
I've had two elbows where the thermostat goes (PI intake, and on the blower), and have never had to put any gasket maker to keep it from leaking. O ring could be bad. New thermostat only costs like $9.

Are you sure the thermostat housing itself isn't leaking? When my old NPI manifold went bad, that's where it leaked at, and I couldn't see any cracks in it either.

Gasket maker is just insurance. Plus you know its not coming from the thermostat housing. Maybe if you had gasket maker on your NPI, maybe it wouldn't have leaked, if saw no cracks.:rolleyes:
 
96gtINP,

O-ring goes on top of the t-stat. You have to torque the bolts down a bit at a time so that things meet up evenly. You should not need gasket-maker. I used a couple of Grade 8 (high strength) washers under the stock washers to distribute the hold-down force over a wider area of the t-stat elbow. I didn't think that the stock washers were stout enough. The other possibility is that the intake is cracked and has started to seep.

HTH,

Chris
 
Gasket maker is just insurance. Plus you know its not coming from the thermostat housing. Maybe if you had gasket maker on your NPI, maybe it wouldn't have leaked, if saw no cracks.:rolleyes:

We tried gasket maker. Didn't work. Water just seemed to seep out of the housing, and we couldn't pin point where it was coming from. End result: crappy all plastic manifold was toast and a new PI one went on.

I had no gasket maker on my PI intake, and it never leaked.

I have no gasket maker on my supercharger; I have taken it off several times, even once while there was still water in it, and it doesn't leak.

OP, you shouldn't need gasket maker to keep it from leaking, although there is a remote possibility that it could temporarily fix the problem. I'd guess that either the O ring around the thermostat is bad, although that shouldn't have anything to do with it leaking water where you are talking about; that O ring doesn't seal up the connection between the elbow and housing. Or, the intake has gone bad as it has to so many thousands of people before you.
 
My 98GT started out the same way with a minor leak, the blew out completely. I opted for the Parkway Performance PI Head Swap Kit! Initially the crack in my plastic manifold could not be seen, but eventually it will just let go.

The PI swap was well worth the time and money. The thermostat housing is cast on the PI manifold so no more cracking.
 
mine had no sign of a crack when i noticed it leaking. looked good as new to me. so i swapped the o ring and it still leaked. finally pulled the intake off and i had a coolant lake in the valley of my motor. it looked like it was only leaking 2 drops at a time....guess i was wrong.....get a new intake
 
Well well well, the crap ole plastic manifold strikes again. Put a new manifold with the aluminum x-over and your problem is solved. NEVER use gasket maker in the coolant system, the excess will come off and cause blockage some where, more that likely your t-stat its self. The crack will be under the t-stat on the plastic landing for the t-stat. Always use a new O ring on these things