Heater started blowing cool air rather than warmer air.
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.
I'd look at the coolant level....and a stuck thermostat~
If it was a stuck thermostat wouldn't the temp gauge be affected also? The temp gauge is normal.
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~
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~
Looking for a Used SL-Class in your area?
CarGurus has 2,732 nationwide SL-Class listings starting at $2,995.
Search Mercedes-Benz SL-Class Questions
Mercedes-Benz SL-Class Experts