I just purchased a 2000 blazer zr2 yesterday.

I have done a quick search and have seen some of the results.

The general feeling is. Air blend actuator, Thermostat, Heater core.

The a/c works great, the heat is very cool, Temp indicator is <175 degrees at all times.

I was initially thinking higher temp thermostat, but a lot of threads state this doesnt resolve anything.

I was thinking of back flushing the heater core to clear any potential clogs, like I did in my wifes jeep liberty, can I do this with a blazer?

Can i test the actuator before replacing it?

Thanks in advance.

Rob

 

take out glove box, the blend door is right behind it. also with the heat on, both inlet and outlet hose to the heater core should be hot, if not its clogged

 

So process of elimination, if both hoses are warm and i can visualize the actuator working, should just need a higher temp thermostat.

I just wanted to through it out for chevy experts before i start tearing stuff apart to replace.

 

Assuming the temp or coolant gauge is correct; <175 is waaay to low! The Service Engine Soon lite should be on.

Replace the thermostat...about a 20 minute job.

Fuel mileage will also improve....although the Blazer is not what you call a high MPG vehicle!

 

Good with the thermostat replacement, have done those before, as for gas mileage, gotta be better than the V8 grand cherokee i just sold.

 

Update - Pulled the thermostat first as the entire running temp was a bit low for my liking, Wow what a surprise. Pic of the thermostat I pulled out.



The temperature of the vehicle is resolved, but the heat still is minimum, I pulled the glove box and manually tested the actuator, I believe we have a culprit.

How difficult are these to replace?

 

Update - Replaced the Air blend actuator, can feel a bit more heat than before (Decent), but it is still not as hot as it should be, next step is to reverse flush the heater core.

Any other thoughts?

 

Nope, seems like your doing what needs to be done

 

Be a bit gentle when flushing the heater core. The passages are small and if you try to put full house water pressure of 60 - 80 psi into it, you will likely get to replace the heater core.