Hey Scotty-
My son was in traffic and noticed the temp gauge shot up on his 2006 Lexus GS430 with 275,000 miles. It almost hit the red zone- then settled back down. It keeps happening sporadically. Spiking up, then back down.
He’s added some distilled water and plans to add more coolant when he gets off work but there was no warning for low coolant. He said there were no leaks under the car or under the hood when he checked.
Any ideas what might be the problem? Temp gauge? Gaskets?
Any help is appreciated!
Check radiator fan operation. It's probably a two-speed setup, possibly the low speed is not working when the engine starts to heat up and then when the engine gets hotter the full speed kicks in.
With that age and mileage, the temperature sending unit is probably malfunctioning. Make sure to bleed all air out of the system.
https://www.autozone.com/engine-management/coolant-temperature-sensor/lexus/gs430/2006
