My Blazer stays at a pretty consistant 165 degrees (according too the dash-guage) but from what i have read in Blazer Forum i am wondering, if i change to a higher temp thermostat, say 195, will this let the computer lean out the air/fuel mix and increase my gas mileage?? Just for info, i live in florida, hot here, but even running at 70-75 mph it stays at about 165 degrees. the only times i ever see it go higher is if i get back in it shortly after parking it, it will read around 190-200 for a few minutes, then back down around 165, and then there is that time the coolant level got low, but that was due too a leaking manifold gasket, which i have repaired...

 

Yeah, that is way too cool for your engine... If it were my truck, I'd hook up my diagnostic tool to it and read what the coolant temp sensor (not the same as the temp sending unit for the gauge) is reading. Do you know for sure that it has a 165*F stat in there? Reason I ask is because with temps actually that low, you should have a check engine light stating something to the effect of steady state temperature not reached in XX amount of time... This should even occur with a 180*F stat as it takes longer to reach the steady state temperature that the PCM is looking for (something around 175*F).

What are you getting for fuel mileage now?

 

thanks for the reply.
About 90%of my driving is inter-state, around 75-80 mph with the air on, and getting around 17.2 mpg this last tank.
p.s. this last tankful had a treatment of techrone in it

 

mine usually stays just under 200, probably 195 and i get an average of 19 mpg

 

It sounds like something is amiss with the temp sender for the gauge...