I've searched and searched and was only able to find one other post that mentioned this, and there wasn't much discussion or theories on the cause, so here goes...

Recently, after driving the car and letting it sit I can go outside about an hour later and the ambient temperature display on the dash will be about 20 degrees hotter than the actual outdoor reading. Yesterday I drove home from work, parked, and then went back out an hour later to run an errand. Outdoor temp was 45, but the display was reading 65. Once I start moving and get some airflow it starts to give an accurate reading within a couple of minutes. Nothing under the hood seems abnormally hot nor do I have any other indications of a hot-running condition.

Anybody else experience this? I've never seen this in other cars I've owned with an outdoor temp sensor. Seems like heat-soak is affecting the sensor as it sits. I could honestly care less about the sensor and might just try to heat shield it if I can actually find it. Just looking for some reassurance that this isn't symptomatic of a larger and potentially more serious cooling issue.

 

It's called heat soak. Most cars, if not all, will do this.

 

I'm sure you're right, but apparently I've never owned or driven "most" of these cars. All of my previous vehicles have been pretty spot-on as far as outdoor temp readings, sitting after being driven aggressively or for long periods of time. I've simply never noticed it before and I've driven the car through 2 miserable summers so far. Guess I'm just curious because I'm not really sure where the sensor is at or what other heat producing components it sits next to.

 

You noticed how much hotter the cabin of your car is opposed to the ambient temperature outside after having your car parked in the sun for a while?

That's pretty much what happens to the amb. temp sensor. It's located right behind the front bumper on the driver side attached to the low-speed impact bar. That little area builds up heat from the sun and engine (heat soak) pretty much like how your cabin does. The only way to cool that part down is to start driving so that the ambient air temp will occupy that area thus bringing the heat soaked amb. temp sensor back down. It only takes approximately 2 minutes for it to cool back down and it's something that I wouldn't care much for.

 

Okay, now that I can visualize its location the erroneous readings make more sense. I guess I just assumed it was in a more free flowing area because I've never seen it give such inaccurate readings before.

Haha, anyway, there I was -- feeling all around the engine bay, sniffing around, etc trying to find some tangible reason for the "hot" reading.