My 2007 LS 460 has developed an intermittent heater problem. The heater works fine when driving at higher speeds but when I slow way down or sit @ idle the cabin cools quickly even if one adjusts the temp. arrow.
Once you regain faster speeds the problem rectifies itself.
Any suggestions on a fix?

maybe check coolant levels???? sounds like it works but might need a coolant flush or check the level.

My 2007 had the exact same problem. Hate to tell you, but it was the water pump on the car. Had to be replaced. Hope yours is not the same problem.

I would check the thermostat and the radiator cap too!!!

Thanks for your answer: Ill check the fluid level and hope its not the water pump

Thanks for the reply - Ill check in to these ideas

same problem here - water pump replaced at dealer. works fine now.

My first thought would be the thermostat. Certainly it is an inexpensive item to replace before you go the water pump route.

Thank you for sharing your information with us. We've seen several reports of water pump failures, but no one ever indicates the manner of failure. Do you know if the pump developed a fluid leak around the impeller shaft? Or was it something like a broken impeller? Or something else?

thanks for the heads up, i will check for his issue. is there a tsib for it by any chance?

The problem was ,as suggested by one person, the water pump which has now been replaced.
Thanks for your help.
Byroncat

The problem was apparently a small leak around the impeller shaft just enough to create an ongoing issue.
Thanks for your interest.
Byroncat

Dealer replaced mine as well, thanks for the heads up!

@LS2k. When you say " the dealer replaced yours". Do you mean it was recall or known issue? If not do you mind asking how much it ran you? Weird thing is I can start the car in the morning and get it nice and cozy. However afterwards it will cool down. Like if I leave the car running when I drop my kid off at day care.

I described the symptoms to the dealer and work was performed free of charge under the lexus platinum extended warranty. Seems to be a well known issue for the '07, exactly like you described below.