Temp gauge goes to hot then occasionally goes to normal then goes back up

RGOTO

MEMBER
2007 LEXUS ES 350
3.5L
V6
FWD
AUTOMATIC
76,000 MILES

Temp gauge goes to hot stays there for a while then drops to about midway then goes back up to hot for a while. Goes back down for a short while then goes back up. Coolant reservoir is full.
Just had water pump replaced. Ac seems to stop working when gauge goes to hot.
Heat seems to be working fine. No performance issues. No warning lights. No visible leaks. Radiator fan turns on.

5 Replies

DOCHAGERTY

MECHANIC
9,601 POSTS

I request some more information please.
The repairs were made and the car was released, and this is when the issue began, yes?
If so, have you been in contact with the agency that repaired the car? If so, what did they recommend?

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Wednesday, August 19th, 2015 AT 7:27 AM

RGOTO

MEMBER
3 POSTS

Repair was done month and a half to two months ago. No issues till now. Having him take a look again today.

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Wednesday, August 19th, 2015 AT 8:35 AM

DOCHAGERTY

MECHANIC
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I am hopeful for a favorable outcome mate

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Thursday, August 20th, 2015 AT 8:39 AM

RGOTO

MEMBER
3 POSTS

He couldnt figure it out. Believes not water pump or thermostat. Any ideas or tests I could do or suggest?

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Thursday, August 20th, 2015 AT 9:38 AM

DOCHAGERTY

MECHANIC
9,601 POSTS

An eight year old cooling system could have a radiator that simply cannot dissipate excess heat, this could be caused by failure to regularly flush the cooling system.
The complete history is unknown and I am not privy to the ability level or competence of the repairing facility you employed.
I would begin this diagnosis with a personal inspection of all components and a review of the history of service.