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Colin T

Coolant Going Down - Leak In Thermostat Area

8 posts in this topic

I've had a closer look at the thermostat housing and using a sheet of kitchen paper to dab around to see which part is wet, it appears that the leak is at the base of the removable thermostat compartment, which I can also see that there are signs of gasket sealant around the joint area with the main thermostat housing unit.

Another job for me to do after xmas.

I'm hoping that this can fixed by dismantling and cleaning the thermostat housing joint surfaces and fitting a new thermostat seal / gasket?

I guess that there shouldn't be any need for gasket sealant compound when fitting a new seal?

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I've had a closer look at the thermostat housing and using a sheet of kitchen paper to dab around to see which part is wet, it appears that the leak is at the base of the removable thermostat compartment, which I can also see that there are signs of gasket sealant around the joint area with the main thermostat housing unit.

Another job for me to do after xmas.

I'm hoping that this can fixed by dismantling and cleaning the thermostat housing joint surfaces and fitting a new thermostat seal / gasket?

I guess that there shouldn't be any need for gasket sealant compound when fitting a new seal?

the housing has become brittle and will need replaced its a known issue

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you should be ok with a new thermostat and rubber seal, it sounds the thermostat as been changed in the past, using the old seal which is a No! No! allways use a new seal, the seal will come with a new thermostat. (dont get antifreeze) when changing it..

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With the engine cold, I undid the 3 screws from the thermostat cover and removed the old thermostat seal.

During which I found chunks of 'translucent squidgy sealant' on the joint faces of the thermostat chamber & thermostat cover!!

Quite a mess

Looked like the previous owner had used bathroom sealant!!

Cleaned the sealant from the thermostat cover and fitted new thermostat seal, fitted cover and topped up coolant.

Started engine and ran for about 15 minutes with the coolant reservoir top off, topping up with coolant as the air came out of the system and the coolant level settled to correct level.

Will now run the car for a few days to see if this has fixed the coolant leak.

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No more leaks - new thermostat seal has fixed this leak.

Seal cost about £1.80 from local Ford garage

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hi am new hear can someone please give me some advise regarding my piece of c##p fusion i had a new engine fitted a few weeks ago because the head gasket want on my old engine due to crack in the water bottle the new engine has been slightly leaking water since it was fitted i could never id were it was coming from in the end i found it was coming from the thermostat housing. now ive took it back to the fella who fitted it and he has told me the head has gone again even though i had a new water bottle fitted before the new engine was fitted there is now since of water mixing with oil or vice-versa the only since was the water boiled over an came out the bottle when it lid was off.

now my question is the the thermostat was ceased when the engine was fitted can that cause the water to boil back out the bottle an because when the bottle lid was on could it cause the seal to go on the thermostat housing when the full unit was sealed the car has never gone in the red it has always stayed below the 90 bar

ii hope all this makes sense

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A leaking thermostat housing will cause all the symptoms you describe except for oil in water, that could be oil cooler although you didn't say if it was petrol or diesel. If you open the cap of your coolant bottle (when cold) and look in you will see a hole in the neck that is designed to let water out should the pressure become critical . Everyone thinks there cracked but I'm not sure. Head gaskets don't go that easy go to another mechanic for second opinion. Those thermostat housings are hard to diagnose as the water tends to dry with the heat, leaks there cause massive pressure build ups and remains pressurized even when cold. Make sure the narrow pipes are not blocked from the thermostat housing to header tank they help to release pressure although when housing is leaking it doesn't seem to work.

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Find a new mechanic as well ide be surprised if you've had 2 heads go finding someone who has a clue would be a good start

The mayo as said can be from the oil cooler not the head it can also be from moisture in the oil due to the mechanic not changing the oil and filter before fitting it if its a second hand engine it can be condensation inside the engine

james1089 likes this

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