Gomez961

I just recently bought a 2006 Lexus IS350 and am having overheating issues. The temperature gauge will raise to 3/4 and then fall back down but I've seen it go a little further at times. I checked the coolant level and for any leaks from the radiator or water pump and everything looks okay. I don't think it's a bad thermostat either because I can visually see that the car is overheating. The guy I bought the car from said the radiator hoses and thermostat were replaced less than a month ago. I don't smell anything funny from the car or see any white smoke from the exhaust. Not sure what it could be?

Also the heat seems to not be working, could there be any correlation between the two problems?

ESully

If the thermostat is working properly, there may be an air pocket in the system. Some automobiles have a bleeder in the system to bleed out air pockets.
At my friends shop, whenever the cooling system is refilled, the car is run with the heat temperature turned all the way up. The fan is also set to low, as high would take more heat from the system slowing the process. A funnel such as this is used to make sure coolant level is maintained.
Automoblile is run till the fans kick in, which signifies the thermostat has opened, but make sure A/C is off as this will cause fan to run before fully hot. Also make sure front of car is not facing down hill.

swaangin

goddamn 200k miles, how's the car been?

GrizzlyMan

Posted in another thread...

With the engine COLD, remove the radiator cap, (have safety glasses just in case), and start the car. Check if any coolant spits out of the radiator cap opening, sign combustion pressure is sipping through the head gasket. The test should not take more than 10 seconds...

Is there a check engine light codes?
These engines never go past 1/2 temp gauge reading, regardless of A/C, leaving it idle or driving it on the highway.
Is the radiator filled correctly, and, just brainstorming, not sure if on these cars the thermostat is placed backwards and if it was replaced at all.

flipside909

I would have gone with an OEM Toyota/Lexus thermostat or even a Denso blue box (first time fit) over a Duralast.

Jazzrock

Not that expensive to buy a radiator with a lifetime warranty, if you need to go that route. $142, though it doesn't show the 14 IS 350 I plugged in. https://www.radiator.com/Shop