Overheating Issue

JONSOLOW13

MEMBER
2001 LEXUS LS 430
4.3L
V8
2WD
AUTOMATIC
107,000 MILES

Recently my wife told me that her car overheats (runs hot) in stop and go traffic. She is not sure but said the issue is intermittent and goes away (the temperature needle goes back down slowly back to mid-point) when she drives without stopping for some distance.

I added a little water (1/2 gallon) and turned on the A/C after starting the engine (cold state first thing in the am). Both fans appeared to be turning.

Can you suggest steps to find the problem?

Wednesday, October 2nd, 2019 AT 1:20 PM

5 Replies

ASEMASTER6371

MECHANIC
52,796 POSTS

Good afternoon,

I would think or start with a thermostat. It may be opening too late.

https://www.2carpros.com/articles/replace-thermostat

Do the fans work without the A/C operating? This would make sense since it does it in stop and go driving.

https://www.2carpros.com/articles/how-an-electric-cooling-fan-works

If she drives with the A/C on, does it still do the same thing?

Roy

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Wednesday, October 2nd, 2019 AT 2:09 PM

JONSOLOW13

MEMBER
133 POSTS

Didn't check to see if the fans operated without A/C. Here in Florida the A/C is almost always on during daylight but I can check and get back to you.
As far as I know, the car overheats during driving where there are a lot of lights where she has to stop, wait, and then go.

My friend and I can check the thermostat. Would that be the next step?

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Wednesday, October 2nd, 2019 AT 2:15 PM

ASEMASTER6371