So I tried to do a search to answer my questions but I couldn't find the answer I was looking for. What is the "normal" operating temp (like what the temperature reading should be) for a 2000 blazer? (or any blazer) what about in cold temperatures? Also, is it possible to have a thermastat issues and not have your truck throw a check engine light? Or, for that matter, is it possible to have other issues and not have a check engine light come on? Or do you just hook it up and see if is throwing codes? Just a few questions I hope there's an answer for.

 

Most 2nd gen Blazers seem to run ~200-210 degrees F regardless of the outside temperature if the thermostat and the rest of the cooling system is operating correctly. I would imagine there are a myriad of issues that could be happening with the engine without it throwing a code. Has the SES light been coming on?

 

Yup, normal operating temperature for a stock 195*F thermostat as referenced from the gauge coolant temp sender should be 200-210*F as rriddle stated.

What's been happening?

 

Thanks guys! Nothing really has been happening...My gas milage is crummy..but it's really cold here too...I was asking the question because the last time I remember my temperature gauge reading above the second line (150?) was when I came home from the UP a year and a half ago. I was towing a 6x12 u haul trailer...it was running kind of hot...anyways..when I dropped it off and started the truck back up again...I had no heat..the next time I turned the truck on the heat worked just fine, still does...except my thermastat is always low. I get exceptional gas milage in the summer...20-22 highway for 134,000 miles on the engine..my SES light hasn't flashed on for like almost 3 years..and before it would do it periodicaly around oil change time so I figured it was just an O2 sensor..reading about thermastat issues..and my recent gas milage (unrelated I believe) I just started wondering if my thermastat isn't broke..which it might very well be..That's why I was wondering if you can have issues and not have a check engine light come on.

 

Your truck will throw a code if it repeatedly sees too low of an engine coolant temperature. If your coolant temp is spuratic, I'd change out the thermostat as a precautionary measure.

 

It never gets any warmer than that second line...not even anywhere close to the middle...so it must be above some low limit set in the computer...I think I might just change it out anyways, as it doesn't seem likeit's an expensive repair..I don't know..it seems the less I do to my blazer..the better it runs (I know that's not the way it's supposed to go) *shrug*

thanks for the answers though!!

 

The limit is something like 170*F after 5 minutes of operation or somewhere there abouts. It is possible that it is satisfying that condition and still not getting all the way into closed loop operation. Best and safest bet is to swap out the t-stat and drain the cooling system, filling it back up with a 50/50 mix of antifreeze and distilled water (hint: put in 6 quarts of antifreeze and top off with distilled water).

 

thanks Kyle...I think that's what it's doing....not cool enough to make it run bad..but not getting warm either...I'll get to it one of these days...besides..I haven't done anything to the coolant since I got it 4 years ago...who knows how long it's been!