91 Ls400 Heater/ Coolant Issues! Help!

[spazzy67]

Hi All!

My heater takes forever to heat up. I changed the thermostat and made sure my coolant is not leaking or blowing any white smoke out the exhaust, but I keep having to top off the overflow bottle. The weird thing is , it seems to heat up faster at higher speeds , then gets cooler as I aproach a signal or get off the expressway!

What could be causing this & what else should I checke or test for furthur analysis. Where is the anti-freeze going???

The top and bottom hoses both get hot.

Thanks in advance for your response!

Paul

B)

[4howard]

I have had a similar problem for about four years on my 1995 LS400. When idling, or stop and go traffic, i get cold air. When I increase to highway speed, the air will gradually warm up and supply satisfactory heat.

After a $2000 trip to the Lexus dealer, the problem was solved for a few weeks. They claimed "my local service station" filled the cooling system with the wrong type of coolant. When I returned with the same problem two weeks later, they told me there was air in the system and that it had to be "burped". The dealer described a procedure where they raised the front of the car in order to force the air out of the system. Winter ended, the problem returned the next season.

Each fall I bring the car to my local service station to bleed and burp the system as described by the Lexus dealer. The fix usually lasts a few weeks. I have never heard what the problem is caused by. :(

[landar]

Replace the radiator(reservoir) cap.

[spazzy67]

Replace the radiator(reservoir) cap.

Is this because its not properly sealed so its sucking air?