Thermostat - Where the hell is it??
 

Where is the thermostat located on a 89GXL??

And can i use silicone as a seal?

Isnt it located under the pastic coolant neck of the water pump?

on my 86 GXL it is located just before the engine on the upper rad hose.
if you have a upper fill cap (for the rad) i is just under there... take the two bolts off, and then take it out.
p.s. drain the rad first.

It's in the same place on both series, sandwiched between the thermostat neck (the tube coming off the water pump that the upper radiator hose connects to) and the water pump.

On series 5 cars, it is plastic and held on by three bolts. It is sealed with a rubber o-ring.

On series 4 cars, it is metal and held on by two screws. It is sealed with a paper gasket.

The Mazda thermostat kits include the o-ring (S5) or paper gasket (S4.) Be sure to buy the right kit.