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No Heat - Temp Gauge RISING!!


hoffy015
12-26-2009, 10:14 AM
This morning my 2002 blazer's heat quit working - the blowers still work fine, just no heat. And, the temperature gauge indicates that the temp level is only on the rise - it reaches points VERY VERY close to overheating...I turn the car off at that point. I have not checked the coolant level yet, but if it isn't the coolant, what could it possibly be?? I replaced the intake manifold this time last year because of a very similar problem. Any help would be much appreciated!!

Thanks in advance!
steph

Rick Norwood
12-26-2009, 10:40 AM
This morning my 2002 blazer's heat quit working - the blowers still work fine, just no heat. And, the temperature gauge indicates that the temp level is only on the rise - it reaches points VERY VERY close to overheating...I turn the car off at that point. I have not checked the coolant level yet, but if it isn't the coolant, what could it possibly be?? I replaced the intake manifold this time last year because of a very similar problem. Any help would be much appreciated!!

Thanks in advance!
steph
You need to check the coolant first. Make sure the Radiator is full to the top and see if this helps. Temperatures reaching that high means one of three things. No Coolant, Plugged Radiator, or a water pump that is not pumping. If adding coolant doesn't help, You might want to flush the system, especially the Heater core.

Rick Norwood
12-26-2009, 10:42 AM
Also take a few minutes to read this thread from the "How To Section"

http://www.automotiveforums.com/vbulletin/showthread.php?t=729213&highlight=basic+cooling+system+advice

Rick Norwood
12-26-2009, 10:48 AM
If you find that your Radiator is full, you could have a thermostat that is stuck shut, but that would not explain the No Heat problem.

Good Luck and Please post back with your results.

hoffy015
12-26-2009, 10:57 AM
But would a thermostat that is stuck explain a rising temp gague? I think that it would only account for the no heat factor.

Rick Norwood
12-26-2009, 11:32 AM
But would a thermostat that is stuck explain a rising temp gague? I think that it would only account for the no heat factor.
Just the opposite. A stuck shut thermostat will block coolant flow and cause the temperature to rise and the engine to over heat.

Conversly, a stuck open thermostat will result in the engine not reaching operating temperature and no heat.

You are over heating but have No heat coming thru the vents inside the car, which steers me away from a thermostat problem, I think you just need coolant.

How hot is the Gauge showing. 210 or is it going up to 260?

hoffy015
12-26-2009, 11:43 AM
Because I caught it before it reached anything over 220ish, it only got that far before I shut it down. I'm sure my truck would have gotten up to 260 had I let it get that far. It climbs up to 210 very very quickly, though. I am away from my truck at the moment and will not be able to check the coolant for another few hours. I will let you know what I come up with when I check it out.

Rick Norwood
12-26-2009, 12:01 PM
Because I caught it before it reached anything over 220ish, it only got that far before I shut it down. I'm sure my truck would have gotten up to 260 had I let it get that far. It climbs up to 210 very very quickly, though. I am away from my truck at the moment and will not be able to check the coolant for another few hours. I will let you know what I come up with when I check it out.
If it didn't go past 220 you're fine, even if it did for a short period before you shut it down you're still o.k.

One more thing, Check the obvious. Make sure the belt is on and the water pump, fan etc, is turning when the engine is running. If the belt slipped off the pulleys, the water pump won't work.

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