LexiJ

My car is pristine, except the heater doesn't work. A/C works perfect. 75K. Any suggestions??

Supruxes

iTrader: (2)

Could be the heater control valve on the fire wall, mine went out and the heater no longer worked, test the solenoid with a multimeter it should test somewhere around 42ohms if its good, if its bad, it will be testing OL.

SC400slide

iTrader: (11)

Bypass the heater control valve. Mine didn't work, and I did this, it still works. And it saves you from buying that 200 dollar part.

https://www.clublexus.com/forums/att...e-img_1937.jpg

https://www.clublexus.com/forums/att...e-img_1938.jpg

Oh, & next time, please search, it will yield many results.

LexiJ

Thanks so much. Is the solonoid located on the drivers side of the firewall? My husband is into Classic American cars, been a mechanic for 40 years, but the Lexus is quite different. I don't have a repair manual but need to get one. I do appreciate your information.

SC400slide

iTrader: (11)

The heater Control valve is located on the Passengers side firewall, to the right of the intake manifold. Yes, the Lexus SC is much more electronic then the 70's vehicles.
Goodluck!

LexiJ

Thank you so much. We have a 37 Chevy Coupe and a 56 Ford PU. Both go to cruise in's. Quite a bit of difference from the SC. Although they have T-Bird and Vette engines, still a lot easier to work on than the SC. I bought the SC in July, owned a 92 and foolishly sold that. My bucket list included another SC. They are so gorgeous and fun to drive. I am going to the garage right now and find that solonoid and test it. Also will locate the person you mentioned and see if I can get a CD. I looked at the manuals online. Good Grief! You are right. Huge.

Once again, many thanks.

SC400slide

iTrader: (11)

Those are only 400 pages long. This PDF manual on a disc is over 4 thousand pages long! It would take quite a few prinnters to put that on paper!

GL

MongooseGA

iTrader: (6)

Will this fix work for a car that takes forever to get the heat going, and only really produces heat when the engine is under a load?

My heat works, sort of. However, it will take a good 5-10 minutes after starting the car to get it hot, and when I come to a stop light the car starts blowing cooler air.

SC400slide

iTrader: (11)

My SC has the bypass and it has the problem you have. Might be a bad thermo as mine is stuck open.

PseudoK

DO what I did, cause this was similar to how mine was, take off the 17mm bolt on top of the thermostat housing, then turn the car on and rev it gently, make sure to top off with water/coolant but you need to get the air out of the system.

tudor

thanks so much!!!!

Ronalder

.

This may sound like a dumb answer but.......

Do you have sufficient coolant in your radiator?

I had the same problem, heat only when moving from 60 up, no heat at stop lights.

I topped of the radiator and the heater was like a furnace.

eknine9

iTrader: (8)

Either you might have air in your system, not enough coolant, or your thermostat is stuck open like has been suggested by everyone here.
Ideally, your car should get to operating temp relatively quickly and stay there so long as the car is on if your thermostat is working properly. If your thermostat is stuck open or you don't have a thermostat the engine will take forever to heat up and will have trouble staying at operating temperature when not under a load.
If you're noticing these symptoms it's time for a new engine thermostat, should be able to find one online for $5-$20.

Otherwise your coolant might be low or there is air in your system. Check your coolant level and run the engine with the front of the car raised up and the cap off your radiator. While it's running, turn the heater all the way up, squeeze the coolant hose periodically , if any air bubbles start coming from the radiator that is air that shouldn't be in the system escaping. Keep going until no more bubbles are escaping, then top off your coolant, and obviously put the cap back on your radiator. Go for a drive and test out the heater afterwards and watch your engine temp gauge to make sure everything is normal.

tom5966

Thanks to eknine9, I resolved my heater problem in short order after checking everything else I could think of. The symptom was simply no heat, no matter what the settings. About three years ago someone suggested it might just be low on water and, although I was skeptical, that turned out to be the problem. I had forgotten that solution until I read a recent post by eknine9 repeating the earlier diagnostic. I checked and it was indeed low on water and after topping it off the heat is ON!!! By the way, there were no other symptoms to point to low coolant level - the engine temperature was entirely normal throughout. Club Lexus help was greatly appreciated!

Dream36

Been having this issue as well. Today I bypassed the heater control valve and it didn't fix it. So I parked on a hill, opened the 17mm bleeder, and filled reservoir. Took a gallon and now heat works amazing. Jus confused to loss if that much coolant :/ oh well it works in happy