Bruce128

I have noticed that the outside temperature reads very hot much harder than the true temperature particularly on hot days if the car is out in the sun. Once I drive it it doesn't drop for long time and often doesn't go to the right temperature. It'll start out 10 or more degrees too hot and then end up just a few degrees too hot. Is it is it broken or is there a design flaw in where the thermometer is?

Droid13

Its normal for the temp to show high when the car has been roasting in the sun. The metal panels of the car will heat up much higher than air temp on a sunny warm day and will affect the temp sensor.

In order for the display to show the proper overall/general lair temp, not only with it take a few minutes, but it has to be a few minutes at enough speed for the air flow to overcome the heat radiating from the rest of the car (and eventually cool it to ambient air temp). If you just pull out into heavy traffic or end up on a multi-lane road where the asphalt is already much hotter than surrounding air temp, you won't get a good general air temp reading. Its a bit like measuring the general temp of your kitchen by holding a thermometer an inch above your stove.

Bruce128

Thanks, that makes sense the only thing is I've had many other cars including a BMW now and they don't act nearly as off on the temperature reading on a hot day as the Lexus, must be something about where they place the sensor

Droid13

If it just never comes around to what you feel is the right temp, the dealer may be able to calibrate it. I've been driving Toyota and Lexus for 20 yrs and I have generally found the temp display to be accurate and usually find the correct temp within 5 min (typically less) of me leaving whatever parking spot I'm at. That said, we don't get the super hot temps of the southern US so not a whole lot of excess heat to overcome.