Leaky therm on A4

[SailingWebGuy]

I just started up my A4 after a minor rebuild. After running for about 20 seconds I noticed that the thermostat housing was leaking from around the gasket.

What would cause this???

A little background - I replaced all of the head studs except for 3 of them that wouldn't come out. One of those studs was for the therm housing. When I put the head back on, I didn't notice if that one particular stud was spinning when I tightened everything back up. Now, it does seem a bit taller than the others...but that could be my imagination.

My initial thoughts are that the stud was slowly pulling out when I tightened them up.

[CalebD]

Did you remove the T-stat housing from the head?
You might just need a new gasket for the T-stat.
Moyer recommends only putting gasket sealer on 1 side of the T-stat gasket. This way it is removable without always replacing the gasket.
It could also be the stud you mentioned. Perhaps that needs some gasket material.
Good luck.

[SailingWebGuy]

I did remove it a put a new gasket back on...but no gasket sealer at all. This might be the problem.

Thanks!

[SEMIJim]

Originally Posted by SailingWebGuy

I did remove it a put a new gasket back on...but no gasket sealer at all. This might be the problem.

Yeah, a bit of gasket sealer, a thin layer, spread evenly, will be necessary. Wouldn't hurt to let it set up or cure a bit, before starting things up, too.

Jim

[deniseO30]

Pray you don't crack the hou$ing! eek!

Moyer Marine Atomic 4 Engine Rebuilding and Parts




Quite a few goodies he has just for that, take a look!

[jaschrumpf]

It would be better to check the status of that stud. Moyer recommends putting the sealer on one side -- the housing side -- so that one can take the thermostat housing off the head without tearing the gasket. Having sealant on only one side of the gasket isn't going to cause a leak unless there's another issue.

[CalebD]

Make sure to remove the old gasket as completely as possible before putting the new one on.
Afourians tend to be a bit anal about different kinds of gasket sealers. Permatex or pemetex seems to be a favorite that comes in a few different flavors. I have successfully used the generic black gasket paste you will find at any auto parts store.
Like SemiJim suggests, the gasket paste needs a short amount of time to set before you try using your new seal.
Check and seal the stud by all means but if water is leaking out from the T-stat housing and the head there is most likely something wrong with your gasket (like no gasket paste).
This stuff is used on airplanes and cars: http://www.permatex.com/products/aut..._Sealant_a.htm