I've a brand new 4WD Thermostat Housing & Elbow.

I've fitted a brand new Ford Thermostat as well.............now its leaking from the joint between the two.

Both faces are flat and clean !?!

I've a new rubber seal (O-Ring) between the two (bought from Burton Power) - is it worth making a thin gasket or using a sealant ?

Can't really understand why it's strung a leak ?

Anybody had the same issues

 

the stat has a special seal round it or should have
the O ring is for stat housing to head face

 

When i changed mine ages ago i used the paper gasket and a thin layer of silicone to seal mine.This was like this for a good 2/3 years.Ive put an updated thermosat in my car now and this time i used the rubber gasket supplied.

The gasket goes round the edge of the thermostat.When i was putting mine in there was a gap between the thermo housings and i thought it wasnt right.I just kept tightening the bolts up till the housing nipped up flush.