Confused over thermostat position in 5 cyl 4kq

[Buchholz, Steven]

... well, there must have been some reason you looked to replace the
radiator to begin with ... was the car overheating before?  If not, I would
think that would be the place to look.  Did they use the same or better core
than the radiator had originally?  On my wife's old Toyota the radiator
looked fine, but I learned that it had been repaired after an accident.
What I later found was that the "repair" entailed shutting off the flow
through only 3 or 4 of the tubes in the core ... and the car ran
considerably hotter afterward.  I put a new radiator in it and all was fine
... 

Another thing that troubles me is the term "aftermarket thermostat" ... most
Audi t-stats actually have two "switches" one that opens the flow to the
radiator and the other that closes off the recirculation of water through
the block that is done to warm the engine up.  If your new t-stat does not
close off the recirc path it seems to me that it would be difficult to get
any flow through the radiator ... all that said, I have gotten the proper
thermostat for my car from a foreign parts store, so they are available.  I
believe the manufacturer is Wahler ...

HTH!
Steve Buchholz
San Jose, CA (USA)
> 
> I had my rad recored on my 86 4kq. The car began to overheat, 
> so I replaced
> thermostat, but it still overheats.  I let the car idle and 
> when the fan
> came on, I removed the expansion tank cap and the tank boiled 
> over each
> time the fan came on until the coolant was very low in the 
> expansion tank.
> It seems the new thermostat is sticking shut? I think I have put it in
> wrong. It is a newer aftermarket style that fails in open 
> position. I will
> remove it today and check its operation in hot water. There is no
> directional arrow on this one unlike the thermostat I 
> removed. Should the
> thermostat be parallel or perpendicular to the engine?