i did the water pump and Tstat 6 months ago, ran great til about 3 days ago.. now the temp gauge only shows 1/4 of the dial ( used to run at 210 on the dial)

it eventually gets to the normal operating temp ( after 1 hour of driving around town ) but then when i get back on the freeway the temp goes down to 150 or so...

do u guys think my TSTAT is defective ( autozone brand )???

i also noticed that the heat is very weak even on high setting

thanks

Most likely stat has failed/stuck in the open position......is it one of those "fail safe" type stats? It's possible the gauge is giving a false reading as well....verify temp with a point-n-shoot infrared temp gun aimed at the stat cover.

can some1 explain what a Fail Safe is?

Fail-Safe Thermostat




Fail-Safe is designed to help protect your engine when overheating occurs. When overheating occurs, Fail-Safe automatically locks in the open position to permit maximum coolant flow.

When standard thermostats fail, they lock in the closed position and prevent coolant flow to the engine, which can possibly cause serious damage to your engine. Fail-Safe has a patented safeguard against overheating damage.

Fail-Safe thermostats are designed with a unique extra stroke that allows operation in two stages:

Stage 1: Within normal operating temperatures, the Fail-Safe operates the same as any other thermostat.

Stage 2:When overheating is caused by a deteriorating cooling system part, the Fail-Safe has a secondary stroke that activates a precision engineered piston that automatically locks the valve into a wide open position allowing coolant to circulate freely.

Note: Once the Fail-Safe thermostat has locked in the open position, it must be replaced and cannot be used again.

What guarantees the "fail safe" will open? Pure gimmick, IMHO, a open stat will not cause a motor to overheat. A "fail safe" stat that has failed open is guaranteed to cause under heat which is a whole different can of worms.

Get a stat from the dealer 52028186. Get your money back on the Dura-Crap stat at Vatozone.