I am having problems again with my heating. I need heat in the Great White North. At idle I blow cold when I rev or take off my heat comes back until I idle again. Last year I had the same problem and the dealer did something with air blockage. I guess in a closed system air can cause problems. How air gets in there I don't know I just know I'm cold. Any ideas on how to fix this maybe problem?

 

Do a search. Plenty of info on it. Check your coolant level.

 

Top off your coolant (even if it looks full), then do a search to find out why it works.

 

Seems im not the only one with this problem, but after 1 weeks at the Lexus dealership they found the problem to be the heater solonoid sticking. It took them a week because the problem only happened to me and when i had it at the dealership it would never happen untill finally it did on the 5 day. Good luck