Apostolis

Hi all, re: 2006 Rx330, 131k. A few days ago my temp needle moved up and radiator fan kicked in. Even with the fan running, engine stays warmer than usual. See no leaks. Thermostat 2.5 yrs old. Suggestions? Thank you

ESully

Wait till the engine is cool and remove the radiator cap. If the level is low you probably have a leak somewhere. Any signs of a coolant leak where you park it? Try to look around the water pump and engine compartment for signs of dried coolant staining. While rare the 2.5 year old thermostat could be a problem.
And of course check the level of the engine oil.

Apostolis

Thx for the reply. No leakage anywhere. Antifreeze level ok. I have a strong feeling thermostat is not opening fully. When temp needle moves up, radiator fan kicks in and it cools off some, but fan stays on for long periods and engine still warmer than normal, first time in 7 yrs this is happening. Now, is it a good idea to replace the water pump and/or anything else besides the thermostat while in there?

ESully

Since there is no loss of coolant, I would think it is the thermostat again. The only other thing might be the temperature sensor.

CaptStumpy

Could be water pump starting to go. When was the last time the coolant was changed?

Apostolis

When thermostat was changed, ~~2.5 yrs ago. Needle does not get to the HOT (red area) but it is staying between 2nd and 3rd line, from the bottom up in the temp gauge. Fan stays on just about the whole time I drive it, especially city driving. Has not done this in 7 yrs. Should I be concerned?

LeX2K

Do you have a code reader? Would be very helpful it will tell you actual engine temperature not what the gauge says which is "fuzzy logic" not the most accurate. Fans should not run all the time.

Apostolis

I don’t have that. But if the fan is going crazy, wouldn’t that tell me that engine is running warmer than normal? Also, if water pump is going bad, shouldn’t there be antifreeze leakage?

CaptStumpy

Pumps can go bad without leaking. Did you use SLLC or Zerex asian coolant when the pump was replaced?

Apostolis

Water Pump was not replaced, just the thermostat. And not sure what coolant the mechanic used. Well, if wp can start going bad without leakage evidence, then that’s prolly the issue. Only 131k but, still, 17 yrs old. Do you suggest replacing drive belts and timing belt as well? Thanks

CaptStumpy

I would borrow or buy a pressure tool and check for leaks in the coolant system before you go and replace parts. There's a write-up here for replacing the pumps. If you're going to do the pump, replace the belt. Its very cheap.

Apostolis

Is it possible for antifreeze being the issue? Old, needs changing? Twice in the past month I added about a quart of water to the reserve coolant tag. Could that have “weakened” the antifreeze? Also, when antifreeze was put in after thermostat was installed, no telling what they put in. A good idea to empty and refill? Which name brand is recommended for this vehicle? Thanks

CaptStumpy

Its not your antifreeze. For this vehicle, the antifreeze color is bright pink or red if aftermarket. Toyota SLLC, Zerex Asian, or SuperTech Asian. Coolant never leaves the vehicle. If it is low, you have a leak. If you pressure test the system, you can verify it.

KIS350

I would inspect the radiator…the thermostat is typically the most common issue and if you’ve replaced it and feel confident in it, then I would check the rad. Visually inspect the fins of the rad. If you have a mesh bug collector in front, I would remove/replace it. If the car is older and been thru several rad shops or mechanics I would take it to reputable service centre for a rad flush. Just some food for thought.🤙🏻 If your car is older it’s a good place to start. It’s surprising how much build-up can happen in a radiator and cooling system. Especially with aluminum oxide and general debris.