Hey guys,
My car heater only blow heat when the car is moving, when I stop at red light then it start blowing cold air instead of heat. This happen also as well when the car idle in (P), then when I give some rev then heat start coming out. Please help me trouble shoot this.

Thanks for all your input.

95 SC400

 

Mine does the same. I'm just too lazy to fix it.

In any case, it is most likely your heater servo or clogged hose

If not, but very unlikely... it could be your water pump slowly going out.

 

Its probably the heater valve.

 

(1) moved to proper forum

(2) top off your coolant.

 

I got $20 on this answer.

 

Ok guys, thanks for all your input. I check the coolant and it full. When the engine is on the coolant tank suppose to be empty on lexus? I know on Honda the coolant in the over flow tank just stay where it is but on lexus all the coolant been suck out of the tank?

 

Nope. You sound low. Burp the system, probably air in the system.

 

anybody have the heater totally go out? my gauge says max hot and blows no air on auto but i can increase the fan speed but it is cold air, almost sounds like a control module, any help would be greatly appreciated

 

^^ search "heater core control valve" or variants of.......

If I had a dollar for every time someone said "my coolant is full" when their heater didn't work I'd be rich. TOP IT OFF. "make it rain"

 

Lemme show everyone this biichen little search engine we got in this here establishment........ This outta turn your grey skies blue...........

https://www.clublexus.com/forums/sho...nt+heater+full

https://www.clublexus.com/forums/sho...nt+heater+full

https://www.clublexus.com/forums/sho...nt+heater+full

https://www.clublexus.com/forums/sho...nt+heater+full

https://www.clublexus.com/forums/sho...nt+heater+full

https://www.clublexus.com/forums/sho...nt+heater+full

https://www.clublexus.com/forums/sho...nt+heater+full

 

^ Thanks OLT

Did it earlier in the morning and my heater is working just fine now.

 

Subtle...

 

I had the same problem and did an entire radiator flush, topped it off with new coolant, and POOF! Like new.

 

**** i know it's late but preciate it yall


-Knowledge