AAL readers, I have a 1992 400LS well maintained with 120K miles on it. Recently I drove to Las Vegas from Los Angeles with the ambient temperature around 110 deg F (120 deg F in Baker) most of the way. Normally the coolant temperature as shown by the guage on the dash is just slightly above the second graduation mark. In the past I have made this trip and the temperature has remained normal or very slightly above normal even when stalled, in heavy traffic with the air conditioning on, for more than 45 minutes. On this most recent trip however I noticed the following. With the car moving at highway speed (40 to 80mph and airconditioning on), the coolant temperature was very slightly above normal. When moving at below 40mph, ac on, the temperature started to increase. When stopped or stop-and-go with ac on, the tempeature started to increase rapidly. I never let it get near the red line. If I turned-off the air conditioning the temperature returned to normal i.e. to the second graduation mark. Returning to highway speed I was able to turn-on the air conditioning again and everything was normal. Inspection of the engine revealed a full coolant reservoir and no apparent leakage. The auxilliary fans moved freely. Since I returned to the Los Angeles area everything has been normal (ambient temperatures around 100 deg F), even when temporarily hung up in traffic. I would appreciate any of your thoughts on what may be the cause of this situation before I take the care to my Lexus mechanic. Your thoughts and suggestions are appreciated in advance. You have a flow problem where that coolant is not flowing well enough. through- out the cooling system if i had to guess i would say you have a faulty THERMOSTAT not opening all the way when it should. thats where i would start looking its the single and "cheapest thing" you can change 1st. make sure you use an original O.E brand and let us know how that works out for? you?
- posted
17 years ago