Heater started blowing cool air rather than warmer air.


Asked by Oct 26, 2013 at 12:31 PM about the 2000 Mercedes-Benz SL-Class SL 500

Question type: General

No problems until yesterday. Heater started blowing warm air and after 20 minutes started
blowing cool air. The auto was not on, as usual I was using the fan to control the air flow. I
elevated the temp to 80 to get the heater to blow barely warm air.

4 Answers

I'd look at the coolant level....and a stuck thermostat~

2 of 2 people found this helpful.

If it was a stuck thermostat wouldn't the temp gauge be affected also? The temp gauge is normal.

3 of 3 people found this helpful.

if the coolant level is normal...the coolant itself is not "rust-water" would "belch" the cooling loop so that it is not air-bound~ make sure the coolant level is okay. the thermostat opens up the cooling loop to the heater core...you MAY not overheat....rust water/clobbered thermostat...aside from air-bound can think of nothing else that it could be~

1 of 1 people found this helpful.

run without the thermostat for a spell and check to see if the heater core is plugged....a garden hose on one of the coolant loop connections with the output going into 5 gal buckets for recapture might happen if the heater core is clobbered with rust~

1 of 1 people found this helpful.

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