The Green Lantern

Got an 04 GT that I had to replace the intake manifold because the nipple on the back side to the heater core(i believe) busted and coolant went all over my windshield, fun stuff. Before that happened the temp gauge read almost 3/4 hot but consistently did that.

When I replaced the manifold i decided to put a 170* thermostat in. Bought new o-ring and also replaced the manifold gaskets and now it takes longer than it used to to warm up and now my temp gauge fluctuates.

When I drive on the freeway its good but since its gotten a little warmer outside it reads 3/4 hot during city driving. Been about a month since i replaced it and I haven't lost any coolant, its still full. Been driving city mostly and it has stayed pretty dead in the middle up until 2 days ago when it reads 3/4 hot during city driving, and i'm not even driving it rough at all.

Maybe fan or something with the heater core?

uberstang1

Heat core really wouldn't effect the temp ready of the engine coolant, check for the fan kicking on, check to see if its burped properly, and try getting an actual temp read instead of going of the factory gauge

blu30val

^+1. And check the ECT with scanner. Don't have specs for voltage at temp, maybe I can find em on Mitchell. The fan makes more sense compared to a coolant temp sensor based on symptom.

school boy

I thought the temp gauge, like the oil pressure, was more like a dumby gauge?

art02gt

if there is air on the coolant system your heater will blow cold. check to see if your heater blows hot.

blu30val

Fans should kick on with heat/ ac too.. simple fan check.

The Green Lantern

Fan turns on when I put the a/c on. The heater blows pretty hot air. I don't know if I burped it properly. I'm not really sure what the proper way of doing that is.

blu30val

I may be wrong, but let the engine run with the reservoir cap off and keep an eye on the level. As it gets up to temp, you may see bubbles and fluid level drop if it has air in it. I don't recall a bleeder valve on a 4.6.l like some of dodge/Chrysler and gm cars. Like I said I may be wrong, but that degas tank is designed to seperate air in the coolant system.

uberstang1

The temp gauge isn't really a dummy like the oil pressure, it will slowly rise and change with temperature rather than off and on position like the oil pressure gauge.

school boy

cool beans! good information to know