+1 on running like crap without tstat. The engine temp will not come up to normal operating temperature without the tstat under normal conditions. The PCM checks engine temp and keeps trying to adjust af misture, timing and other things based on temp. Being outside the correct range will not allow the PCM to settle into a normal operating routine.

 

Bad coolant temps can cause massive issues with fueling. You're probably pig rich and the engine can't burn off all that excess fuel.

there are certain vehicles where removing that tstat can actually cause an overheating situation, as the coolant passes thru the radiator too quickly and doesn't agreed all of it's heat. Lots of racers have that problem, they usually run a Moroso restrictor, which is essentially a large washer in place of the tstat, which restricts the flow a bit to slow down the coolant flow.


the truck radiators are large enough that i don't believe that to ever be a problem, unless maybe you were hot lapping at the track.

 

We have cold nights here-down to about 20° on cold nights, but the days are rarely below 50°. I have had no problems since ditching my t-stat a couple years ago. After about 10 minutes my engine temp is up to the 2nd line and stays there. But each beast has its' own personality.

 

Yea OK.