I have a 1990 Runner with 151000 miles and am looking to replace the thermostat[no heat at idle].Where is it located and is it a difficult job?Thanks in advance.

 

Welcome to the forum.

It is the housing the lower radiator hose ends up at on the eingine side. It has (3)12mm nuts holding it to the water pump.

Remove skid plate.

Drain the coolant in a suitable container.

Place container under thermostat housing.

Remove 3 nuts and housing.

Install new thermostat and gasket.

Re-install housing and 3 nuts.

Fill coolant. Burp cooling system. (Suggest removing throttle body hose till coolant flows out, or by removing the upper radiator hose from radiator and filling engine specifially).

Inspect for leaks.

Reinstall skid plate.


Jay

 

I recommend using only a genuine Toyota thermostat. And point the small jiggle valve pointing up. Also when refilling , remove the upper hose and poor coolant directly into the engine ,this helps burp the system faster. Daryl D

 

And be careful when you take off the part that bolts to the water pump (where the lower hose attaches). When I tried to take mine off it was kinda stuck and I had to pry it off. Little did I know it is plastic and I scratched the seal surface a little. Luckily it still seals ok.

Steve