2002 Blazer LS 2WD 4D 65k miles

Had the service engine soon light come on. The only thing I can notice is that the temp is registering low. It is reading 150-160. Any ideas? Heat is blowing just fine. Fluids seem ok and nothing looks disconnected (at least that I can see).

 

Sounds like a bad thermostat to me. You should verify that the temp is actually low as well as get the code read. A thermostat can stick open, reducing the system temperature and not drastically affect the heater output inside the vehicle.

 

Thanks for the info. Took it to the shop this morning, so I will post the outcome.

I had someone else tell me it may be the thermostat, and then another person told me that if it were the thermostat it would be running hot, so it is probably an 02 sensor. Should hopefully know soon.

 

Most thermostats are fail-safe now. Which means, if they fail, they fail in the open position.

 

So does that mean that if it fails in the open position, it could possibly cause the low temp.?

 

Got it back from the shop. Here is the write up:

"Check engine light on, ran diagnostic test, (extended time to reach operating temperature) drain coolant, replace thermostat and seal, refill coolant, purge air from system, clear computer, retest operation."

$108.87 TT OTD

Vehicle heats up just fine now.

Not too bad...

 

Thought it would be about that. Sad part is, the thermostat costs around $15 for a good one and coolant would be around $10...