Thermostat housing leak
 

I keep having a termostat housing leak when I pressure test my system. Mostly from the bolt closest to the engine. It actually looks like is leaking through the bolt hole. Have I mixed up my bolts and its to small?

An Im curious as to what people have been using for a method when installing a thermostat. Thermostat in with with blue RTV followed by gasket? Or no rtv? or No gasket?

Perhaps the threading on that particular side has a crack in it. You wouldn't be able to get the bolt tight enough to properly seal. You must use the proper torque specs when it comes to things like this.

I go thin layer of blue RTV > thermostat > thin layer of blue RTV > gasket > thin layer of blue RTV > coolant filler neck

I hand tighten it ever so slightly. One hour later, tighten it a bit more with a wrench. I let it dry for 12-23 more hours and then tighten it completely.

88?
2-12mm bolts hold the thermo neck to the waterpump housing.I install the thermostat,Pointy side up!(ALWAYS a OEM thermostat..always.)
then i just skim the surface with rtv,Rub it on with your finger,Install the gasket.Put another dab on the Thermoneck.Install the neck and bolt it on.
The cap portion of the thermo neck that is held onto the neck with 2-10 mm bolts has a O-ring under it.Located in between the Plastic part that the rad cap attaches to and the thermo neck.If that o ring is missing it will leak.It usually doesn't deteriorate as that part is never taken off for any reason.
You can get that O-ring at any auto parts place,just bring in the plastic portion and match the size up.
DW!..I had to spellcheck..you're too quick for me!

Did you get this resolved?

I just use a roll of coolant gasket paper (different rolls of material for different stuff) Cut out a gasket and bolted it all together. Hasn't leaked on me since installed a few years ago and i daily my 7. Its a S4 with the metal filler neck too. I'd take it apart, throughly clean everything and look for cracks.

Yea it did kind of got resolved. I did the blue / gasket / blue but I only waited a couple hours. look like it leaked a little but stopped.

On too the other 30 problems I need to fix with this 24 year old car that I decided to make a daily driver.

I keep heating up if I get on boost on the hwy (think its my timing) and I have fuel cut off at 5psi according to my boost gauge..

Save yourself a lot of aggro and put studs in the housing instead of bolts.
Ones like the waterpump flange (where the fan mounts) work perfectly.

That area is a disaster waiting to happen...steel bolts into an aluminum housing cooked by heat and marinated with coolant.
Studs eliminate the issue entirely.

until the stud snaps.

*giggles and runs off*

Yea I've been there. My first 88na i sheard off a bolt and had to drill it out and it was never the same.

So your saying I should take the studs out and put in bolts?

Life is difficult for the ham fisted.

*giggles and takes a nap*

Do you have a undertray?

There's an awful lot of giggling in this thread :suspect:

No, he said the opposite. Bolts out, studs in.

I didn't at first, but after I bolted it back on it made some difference but it wasn't massive.