ive ben fighting with my thermostat housing for a week now.

heres what has ben done

1. pulled of the housing because it was cracked and found out that it didnt have a thermostat
2. JB welded the housing,got a thermostat,got gasket meterial, and put it on
3. it was leking realy bad so i did it again
4. still leking pulled it off to find out it was cracked in two mor places(JB welded again)
5.replaced with new gasket, still leking, got worse now
6.removed thermostat wit the same results

so as you can see i cant get the dam thermostat housing to seal at all.

a thought was to take my water pump housing from my 88 parts motor and put it on my 90 motor, so i can use the thermostat housing for that and have it seal beter

so i guess the question is will a s4 water pump housing fit on a s5 motor ?
if so will i need gaskets and will i be able to use gasket meterial or just silicone?

 

dosent any body know?

but if no one does im just gona try and find out myself

 

The leak is where the t'stat housing meets the engine? If so, the mating surface of the housing is likely warped. Get rid of yours and buy a good used one. The cooling systems on these cars must be right, or the potential for big trouble is around the corner if you overheat them.

 

I though you could change the housing, as long as each the same eg Turbo or N/A, but according the this thread the housing hits the omp:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/waterpump-compatibility-294008/