T-stat housing Paint?
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T-stat housing Paint?
i am having trouble with leaks at my thermostat housing. i have read a few of these forums where i need to lightly file the surface of the housing to make sure its smooth and without defect. same for the engine housing only with that i plan to use mild sandpaper on a block.
my question is this - do i need to paint these surfaces after i get the surfaces true and before i mate the housing to the engine block? i am wondering if the paint will alter the mating surfaces and create new places for this to leak when under pressure. on the other hand, these are metal and while mated, air can still get in there and slowly those surfaces will corrode.
any advice on this?
many thanks!
my question is this - do i need to paint these surfaces after i get the surfaces true and before i mate the housing to the engine block? i am wondering if the paint will alter the mating surfaces and create new places for this to leak when under pressure. on the other hand, these are metal and while mated, air can still get in there and slowly those surfaces will corrode.
any advice on this?
many thanks!
Fleet Mechanic
Joined: Dec 2016
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Not a fan of gasketing over painted surfaces. Certainly would sand/file surfaces flat but being careful not to reduce the recess that aligns the thermostat. If too much is taken off, it will always leak as you'd be tightening against the thermostat and not the mating surfaces. Also, since you said you had problems in the past, make sure that the thermostat is indeed set within the recess and has not shifted before tightening. If either surface is heavily pitted, silicone is good for filling in larger than ideal voids.
You can paint everything after it's back together and the additives in your coolant will prevent corrosion from the inside
You can paint everything after it's back together and the additives in your coolant will prevent corrosion from the inside
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Thanks! just the answer I was looking for. appreciate the other tips as well. I was going to use Permatex #2 gasket sealant on both sides of the housing gasket. is that the silicone you are referring to? also, the thermostat itself just sits in the groove on the housing and is not cemented in with a Permatex type gasket material? my thermostat moves around just a little in the notch in the housing. should it be a precise tight fit?
Fleet Mechanic
Joined: Dec 2016
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I was going to use Permatex #2 gasket sealant on both sides of the housing gasket. is that the silicone you are referring to? Basically, yes. Might be one more specific to be used on thermostat housing/engine coolant though. also, the thermostat itself just sits in the groove on the housing and is not cemented in with a Permatex type gasket material? Correct my thermostat moves around just a little in the notch in the housing. should it be a precise tight fit? No
Tuned
Joined: Oct 2018
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I have never used ANYTHING but a gasket on thermostats. And I have never had one leak.
Silicone will cause leaks, because the gasket can now slide, easily (silicone is a lubricant).
If the thermostat housing is corroded, buy a new one, or machine the old one (if possible, usually not possible).
The factory did not use any sealant on these in the beginning, AND they guaranteed the whole car for a good period of time (varied with manufacturer).
That said, it's your car/truck, do as thou wilt.
Cosmo
Silicone will cause leaks, because the gasket can now slide, easily (silicone is a lubricant).
If the thermostat housing is corroded, buy a new one, or machine the old one (if possible, usually not possible).
The factory did not use any sealant on these in the beginning, AND they guaranteed the whole car for a good period of time (varied with manufacturer).
That said, it's your car/truck, do as thou wilt.
Cosmo
See A Man About A Horse
Joined: Apr 2003
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From: Mariposa, Ca.
I, on the other hand, always use a thin layer of silicone in addition to a gasket, and have never experienced a leak at the housing.
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Logistics Pro
Joined: Jun 2018
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Beg to differ, but a clean surface and a quality gasket is all you need. Could you imagine all these guys on the assembly line squirting goop on everything, Not.
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Fleet Mechanic
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Tuned
Joined: Mar 2017
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Use the silicon only if the gasket surface is pitted and you do not want (or cannot) replace the parts. Or....if the gasket is no longer available. The trick to using silicon gasket is to 1) apply evenly to surfaces, 2) Important - let it dry to a slightly “rubberized” hardness before assembly of parts.
If your surface is clean, flat, non-porous, use the correct replacement gasket.
If you need to use the silicone gasket due to surface irregularities, use only the silicon, no gasket.
If your surface is clean, flat, non-porous, use the correct replacement gasket.
If you need to use the silicone gasket due to surface irregularities, use only the silicon, no gasket.
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