I have recently experienced an issue with my heater not working properly. I was driving for 45 min in 28 degree temperatures and the heater was blowing a mix b/w hot and cold air. By that I mean it would blow cold air pretty much the whole time but every once in a while for about a 30 sec window it would blow hot air, then right back to cold. When the air was cold it was ice cold like the heater wasn't engaged even slightly but when it was hot for that 30 sec it was as if the heater was working perfectly. I turned the heater on and off, changed the output from defroster to cabin, changed the air flow from external to internal with no effect. Have never had a problem with this vehicle of any kind to date. Your suggestions would be greatly appreciated,

Thanks

 

What is the engine temperature?...... Does it get hot?

 

Check your engine-coolant level. Occasionally these cars develop an air bubble in the cooling system if the coolant level gets low and a special effort is needed to ensure that all the air out.

 

The running temperature of the engine was completely normal but I just checked the coolant level and it is low. Is there a special kind of coolant I should use as I'd like to stay consistent with what is being used already which is pink in color.

 

The coolant is Toyota brand. The reason that the coolant is low may be related to a leak, or insufficient refill after some sort of maintenance such as hose or water pump replacement, or coolant cap not properly tightened.

 

BMW cooling systems need to have any air bubbles bled out of them or you will get these symptoms (they have a bleed valve on the top of the radiator). Don't know if Lexus has the same requirement.