Well, I have a 2002 S10 Blazer 4.3 4x4 LS

I used to have a 1995 S10 Blazer 4x4 LS

* Well currently heat does not get hot unless drving fast........

* The temp gage says 170 at idle..........

* Temp gage goes to 190 when driving fast.........

Could my thermostat be stuck open? causing my vehicle not to heat up to the standard 210

heres what i can tell you

I know when its in the DEFROST setting that it slighlty blows out the vents....(shouldnt do that)

I know the temp switch control itself works, cause if i turn it to the cold side it get really cold, if i turn it to the hot side it gets a little warmer (SO IT MUST BE OPERABLE)

I dont think its a vacuum problem, because i think if it was a vacuum problem, my 4x4 wouldnt activate. (because correct me if im wrong the switch for the 4x4 electrically controls a vacuum diapram to activate my front axle. That is the way it was on my 1995, when the little round vacuum ball was unplugged on my 1995 blazer my 4x4 front diff wouldnt lock in and my air system would default to the defroster vents only) Again the 202 blazer could be differant

DOES ANY ONE KNOW OF ANY OTHER KNOWN ISSUES THAT IT COULD BE

 

Are you low on coolant?

 

dont think so, i popped the radiator cap, and it look full, and there was some in the resevoir

 

i know it sounds ignorant of me, but why would it not overheat if i was low on coolant, how would it seem to stay overcooled

 

It was just a thought. When your blazer is warming up, does the gauge go up to 210, then drop down or does it stay around 170 the whole time?

 

stays at 175ish unless driving fast.....then 185ish to 190

the only thing i can figure is this weekend give it a whulr and change the thermostat'

 

I have the same condition. And I have narrowed it down to a plugged heater core. Check your heater hoses and see if one hose is hotter than the other, this will tell you if the core is restricted....just have to reverse flush the core only and that should fix it. It only takes a few minutes and a couple of pieces of hose to connect onto the core at the firewall so you don't get coolant all over the place. You can use a large bucket to collect the coolant then take it to be recycled.

Or you can flush the complete system with a Prestone Flush-n-Fill kit. Although be aware that this method will not completely flush the heater core which is the real problem.....

 

That definitely sounds like a sticking t-stat. Throw in a 195 degree stat and do the heater hose check that 20Blazer00 mentioned.

 

How long does it take to warm up in the morning?

I jump in mine and drive and about 2-3 miles down the road (with a 30*F outside temp) it's up to temp and blowing hot air at me. However, my truck runs at 175-180*F all day long, summer or winter. If I really push it (WOT A LOT), it may rise up to around 190. It is possible that you've got a 180* t-stat in there. I'm not sure if that is my case, but when I do a flush/fill, I'm replacing the stat with a 195*F anyway. That will happen this summer when my Bravada won't be used as much.

 

i will try to flush this weekend, if i remember i must put stuff in, drive around, empty......then i will change the thermostat while it is emptied, then i will fill with fresh anti-freeze..........i left it running for thre hours today, jumped in and it was cool.......but when started driving warmed up, especially at "WOT".......second came to light, blowing cooler air again