My heater in my 99 SL1 is only blowing lukewarm. I replaced the thermostat which helped a little but not much.What else should I do? Edited by: steviedpeters

is your coolant level full? how dirty is the coolant?

I replaced the coolant and the coolanttemp sensor as well. Still not blowing as warm as it should be.

1) Is the engine cooling fan running all the time ?


2) Are you sure you have the heater control fully open ?


3) Have you flushed your coolant system?


4) Check the hoses going from the engine to your heater, and make sure they are not pinched closed ...