I just replaced my thermostat and now the truck gets hot real quick. I took it out to make sure I didn't install it backwards. It was in the right way. The heater finally gets hot but the damn temp gauge goes from cold to hot in about 5 minutes. What could be the problem? And just for grins, someone explain to me like I'm a 5 year old, which way to install the thermostat, just in case I've lost my mind.

 

Side with spring goes toward motor dome side goes toward radiator

 

yeah...and what temp T-stat did you buy...and why did you replace it to began with ??

 

I replaced it in hopes of making my heater blow hot. Well, since posting this, I believe I have fixed the problem. Turns out I did put it in the right way. I drilled a 1/16 hole on the flange and that did it. Guess I had an air pocket that was throwing it off. Don't know what temp it is though. Just asked for an OEM replacement. The heater works great now. Thanks for the info guys.