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Thermostat housing leaking coolant

NickHidro

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Hey guys, sorry if this has been covered before but I'm struggling to find the right answer I need.

I have coolant leaking from the thermostat housing where it meets the block and cannot for the life of me get it to stop using just the gasket.

I've cleaned both surfaces to the point where they're spotless and I still can't stop the gasket from leaking.

Should i try using that gasket goo stuff rather than those stupid paper gaskets or am i still doing something wrong?

Cheers for any help.
 

lout

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my daughters car has same fault
i replaced the housing - no change
i made my own thicker gasket which fixed problem
i believe the thermostat is too thick or the manifold recess is not machined deep enough
 

wortus

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check the mating surfaces for any distortion. have you thought about trying a sealing silicone instead of a gasket and gasket goo? It may work better especially if the surfaces are slightly distorted, uneven or a bit corroded etc.
 
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devilly

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i used that blue silicone sensor safe goo and gasket on mine :)
 

greenacc

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As devil said I use whatever paper gasket is supplied and put a bead of gasket silicone or permatex #3 on it. Just don't go nuts and put too much on it it makes a huge mess and gets into the coolant.
 

NickHidro

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As devil said I use whatever paper gasket is supplied and put a bead of gasket silicone or permatex #3 on it. Just don't go nuts and put too much on it it makes a huge mess and gets into the coolant.

Cheers for the advice, I'll give that a go tomorrow. When it comes to applying the sealant stuff, how wide should the bead be? I've never actually used it before so i have no clue how it works.
 

greenacc

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Not too big, something like the size of the ink tune in a biro run around the centre of the gasket.
When you bolt it up most of it is going to get squeezed out so its pointless going overboard with it and it can block radiators etc as well there's too much.
 

NeddyBear

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Bugger that sounds rough, just recently when fitting a new belt tensioner I had to remove the thermostat housing when the new way to thin O ring came off the tube and fell into the cavity under the housing.
I have a Holden thermostat and gasket and cleaned both surfaces and refitted the gasket and then drove 1500 klms and not a drop leaked.
Several years ago when I rebuilt everything heating and cooling related another guy mentioned to be careful of the seatting lip on the Thermostat and that's why I went with the Holden unit.
 

NickHidro

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Bugger that sounds rough, just recently when fitting a new belt tensioner I had to remove the thermostat housing when the new way to thin O ring came off the tube and fell into the cavity under the housing.
I have a Holden thermostat and gasket and cleaned both surfaces and refitted the gasket and then drove 1500 klms and not a drop leaked.
Several years ago when I rebuilt everything heating and cooling related another guy mentioned to be careful of the seatting lip on the Thermostat and that's why I went with the Holden unit.

One thing I've noticed when fitting the gasket is that the inside part of the gasket sits on top of the thermostat slightly. I don't know if this is normal or not but do you think that could have something to do with it?
 

Brisbarnz

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I use gasket + ACL Holamar spray. Some take an oring. Depends on model.
 
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