Non-update update:

It spent a week at the dealership. Bottom line: they drove it around for 200 miles, but was never able to re-create the problem. Said my coolant system was fine, no leaks, levels were good, and the thermo was good. Oh well, at least I have it on record that there was a problem and I took it in, but they couldn't find the cause.

 

My 09 LS460 is just beginning to do the same thing. Every once in a while the temp gauge pegs out, I immediately turn off the AC, then it goes to normal operating range (center). Plus in last couple days heater blows cold. Classic indication of low coolant. Took the front cover off and put about 48oz of water in the reservoir this morning. Heater works fine, gauge doesn't peg out, or at least not on the 15 minute drive to work. Will continue to look for possible leaks.

My question: Is there a quick or simple way to view the water pump weephole for signs of leaks? I see no other sign of coolant escape so far.

Thanks in advance...

 

Once you've removed the engine covers, you'll be able to see the water pump. Classic symptoms of a bad pump will be pink clumps of dried coolant, usually near the top of the pump. You really can't miss it. It'll look like this and looks like something from a B grade horror movie:

 

Just wanted to share my image of mine when it was going bad.
I hadn't experienced any issues, I was just looking around because after being so involved in the forum, I figured why not take a look, and bingo! It was leaking.
LOL@ B grade horror movie!

 

These pictures are making me want to go out and look to see if the aliens have gotten hold of my water pump yet. I noticed that my coolant was just a bit low, so maybe they're already there!

 

Lexus Master Tech here,

Classic symptom of low coolant. 99% of the time with the LS460, it is a leaking water pump.

 

leaking water pump and/or leaking radiator / hoses, connectors

 

You have air trapped in your system. Jack the front of your vehicle up like your on a steep incline and burp your system. Google how to burp system with lisle funnel.

 

My temp sensor had spiked twice in the past two or three months. After reading this thread, I decided to take it to the dealer. It was a valley plate coolant leak. Lots of labor to change a cheap part. TG for the warranty.

 

Does this generation car have a thermostat. When I search for the part only this comes up is

Thermostat Housing - Lexus (16323-38030)

• List Price:$83.13
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• Sale Price:$59.98

This part fits your 2007 Lexus LS460Change vehicleADD TO CART

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Manufacturer WarrantyMinimum of 12 Months
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Same thing happened to my 2011 LS460L. Turned out the be the Heater Exchange Plate. The service included replacing the intake gasket, throttle body
gasket, o-rings. Total cost covered by my CPO warranty: $1548.96 + tax.

 

Hi melymel96, what was the ultimate solution to this problem? Did you replace the thermo?

 

Thank you for this post, my 2009 LS460 is just now beginning to show thermostat issues! I really didn’t hit the highway much 2020-2022, only use my car as a daily and barely put 2-8 miles a day being everything I need is within a 5 mile radius out here in SW Houston. Anyways, that engine overheated sound is the worst sound to hear besides the low oil light, or that damned Check ABS brakes light when your brake pump actuator acts finicky. All of these issues are common false lights on these LS series 2007-12 but make sure to have a reliable mechanic who won’t charge you too much to diagnose these issues. The Lexus dealership now requires 189.00 for a diagnostic fee. Which use to be a free service before 2020 believe it or not! I have wasted plenty money running to these crooked dealerships as my car has just begun to start showing age issues obviously. I am going replace my thermostat sensor as my car tends to do it even more in these hot Texas summer months. I had all my fluids checked, everything was fine!

 

Hello, fellow Houstonian. If you have not done so, get the system pressure tested to rule out other issues. In my case, which had identical symptoms, a pressure test revealed the valley plate was leaking.

 

I have a 2011 CT200h with 230,000 miles on the head was replaced 3 years ago. The car would overheat on an incline so the first thing i did was turn on the heater but no heat would come on. I do run a scan tool so i can keep track of the temp because the CT200h doesn't have a gauge just an idiot light. Just recently the heater would take some time to start blowing hot air and the temp would start to rise id pull over to the side of the road and then it cools down. The other day it did it again and this time a i turned off the car and restarted it and as soon as it started hot air came out of the heater and the temp was back to normal. I have replace the thermostat and the coolant sensor i did use factor parts. The dealer cant seem to duplicate the issue. The engine does over heat because there is some coolant that leaks through the cao and yes i did replace the caps with factory ones too. thanks