Originally Posted by perumotors1369

I would scan it with a scan tool and see what that says...may be right on, temperature wise..

Originally Posted by BamaZR2

Ok. So I put in the AC Delco stat that I bought, and the temp gauge is still only reading between the 6th and 7th mark which should be around 190. I was expecting something at or above 200°. Fan clutch is new AC Delco, and radiator is also new. So where you from here?

Originally Posted by Rock18

Yeah an OBD II scanner if one is handy could give a more precise digital readout



But as was said earlier, 190 is now into the optimal operating temperature for these now and 190 is about where mine runs; not sure why you might expect above 200. Running it hotter than optimal probably wouldn't even help MPG much. Frankly I'd let it run a 190 for a tank or two and see what it does.

If you really want to experiment you might just try blocking off airflow to part of the radiator with a piece of cardboard etc. to make a "redneck thermostat." Just be sure to remove it before hot weather sets in.

If you're still not getting the MPG you think you should it might be time to look at the plugs, cleaning the MAF etc. Running a bottle of injector cleaner through it couldn't hurt if you haven't do so lately either.

Originally Posted by BamaZR2

Hey Y'all,
I've got a 2000 Zr2 Blazer I've had a ton of work done to it. Most recently I have replaced the radiator, fan clutch, and thermostat. Fan clutch is ac Delco, stat is 195° duralast. MPG is right around 13 mpg even with these changes. The temp gauge is showing around 180 which isn't what it should be I know. Before the stat change temp was staying around 160°. From some of the posts I've read on this forum this far I'm seeing that the operating temp should be about 200°. My question is, how much if a difference would the extra 20° of temperature make if any as far as MPG and overall performance? Oh and tires are OE size but less aggressive tread pattern than the BFGs that it came with. I never drive faster than 70 and I usually keep it around 65 on the highway which is where the majority of my driving is done. Thanks in advance.

Originally Posted by Matthew Anglin

My 1995 blazer with the old cpi vortec motor gets 20-23 mpg and that isn't taking it easy on the pedal either. Mine did get 18 mpg before all the work I done to it i recently changed the whole front end suspension parts to hubs and axles all new, I replaced my o2 sensors thermostat with a 180 degree temp, coolant flushed and replaced, alignment is all I've done to it and got 20-23 mpg all the time just about i get 23 going 75 mph on the interstate and get 21 in royal areas going 50 mph lol speed limit is 45 tho i always try to keep overdrive engaged