I have had my blazer for a little over a week now and I have no heat and the engine never warms up more than like a 1/4 of the gauge...so like 100'ish I guess. I read about every thread on here on the issue and on .com trying to see what my next step should be. So far i have replaced the thermostat, and done a coolant flush. Neither of these things seem to have fixed the problem. What should I try next? I installed the thermostat the same direction the other one was in with the spring facing downward. I suppoe it is possible that the new thermostat was faulty, but thats not likely.


Its a 96 Blazer LT 4 door 4x4, 165,000 miles, 4.3L Vortec. [/align]

 

fan clutch seized ? just a guess ..

 

did you bleed the air from the system after the flush and thermostat replacement?

 

How would I be able to tell if the fan clutch was seized? If it is, how costly will that be to fix?

A shop did the flush for me, i would assume that they know what they're doing (i could be wrong though haha). But the problem is no better or worse sense the flush so im guessing it was done correclty but was not the problem.

 

if i remember right someone said (swart maybe?) spin the fan by hand it should do a full 360 revolution if not the clutch is bad, i could be wrong but thats my recollection from reading it (not sure if that was these forums or the .net ones) i'll try to find it and link the post.
AHA! wasn't swart but rriddle3 that posted how to test it read it yourself for more detail https://blazerforum.com/m_132317/tm.htm hope it helps!

 

A seized fan clutch would also make it pretty hard to drive. When mine was bad I had almost no power and it sounded like I was hiding a couple shop vacs under the hood. I would try and make sure that the engine is actually staying cool, and its not just the gauge doing weird things.

 

So if the fan clutch is seized, does that mean that the fan is not running at all? Or running all the time?

Because if it is seized and the fan isnt running at all wouldnt that actually make the car overheat?

 

A fan clutch can fail either way...but usually, they fail engaged. So the fan is on all the time, even above the safe RPM limit of the fan. And actually, when my fan clutch was seized and it was engaged all the way up past 3000 RPMs, it was causing my engine to overheat as it would block the air flow at highway speeds.

 

Outsydr, you have to go back a bit further for my explanations (just one example).

In this case, a fan clutch that is fully engaged would not cause this condition. The thermostat is in total control of how hot the fluid is in the engine. If the thermostat has been replaced, I would be checking the actual temperature of the coolant with either an infrared thermometer or some other means of testing with a gauge other than the one on the dash.

Do you get heat out of the HVAC after a few minutes of operation?

 

Just went and checked the fan. I can turn it freely as much as i want to when the car is turned off. It is about 23 degrees right now and when i turned the car on the fan immediately came on too. Is this normal operation for the fan when the temperature is that low?

I get little to no heat out of the HVAC after even hours of operation on the highway at 65+. And the temp gauge stays around 100 to 110 the entire way.