2UZ-FE Normal Operating Temperature (6 Viewers)

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Asphalt direct temps here in Las Vegas goes upwards of 165°F and that is a big contributing factor of the radiant heat.
 
Reporting back after 100+ degree days. Vehicle runs cooler than it did pre clutch fan drain with 30k cst fluid. Highway driving in the summer the ECTs are 189-191 with no vehicles directly in front of me. Went through a busy drive thru and temps started creeping up more slowly than usual ~205 degrees until I set it in park and accelerated a bit to get the fan moving. Transmission temp was up ~200 degrees. Accelerating drops the temps for both ECT and Transmission. Once I start driving again the temps drop quickly. Noticeable difference in HVAC temp.

No issues in colder weather but this heat is brutal.
This sounds very normal to me, given the outside temperatures we’ve all been experiencing. I’ve seen similar in my 2000 over the last couple weeks.
 
It's still very hot here in Arizona but I have finally gotten the engine temps down to a reasonable number! The problem was a faulty OEM Thermostat that was purchased in 2024, barely a year old. Maybe the plunger wasn't extending enough to cool it down, I'm not sure. But the OEM Tstat purchased from Bell Lexus was running my engine at 204F. Engine temps would climb up to 215 and even higher just slowing down to make a turn or park in a parking lot.

Anyways, the thermostat I just put in was a MotoRad 170F Fail safe from Amazon. I don't really like the design in comparison to the OEM but it is functioning appropriately! Right now my 100 can Idle at 190F ECT with the Ambient temp 105F and Ac blowing 49F out of the vents! In Park with the idle bumped up to 1500rpm it would go a bit lower!

Still have some vacuum leaks that need to be fixed. Just the lower Denso grommet on the lower fuel injectors. Other than that the truck runs really well!

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It's still very hot here in Arizona but I have finally gotten the engine temps down to a reasonable number! The problem was a faulty OEM Thermostat that was purchased in 2024, barely a year old. Maybe the plunger wasn't extending enough to cool it down, I'm not sure. But the OEM Tstat purchased from Bell Lexus was running my engine at 204F. Engine temps would climb up to 215 and even higher just slowing down to make a turn or park in a parking lot.

Anyways, the thermostat I just put in was a MotoRad 170F Fail safe from Amazon. I don't really like the design in comparison to the OEM but it is functioning appropriately! Right now my 100 can Idle at 190F ECT with the Ambient temp 105F and Ac blowing 49F out of the vents! In Park with the idle bumped up to 1500rpm it would go a bit lower!

Still have some vacuum leaks that need to be fixed. Just the lower Denso grommet on the lower fuel injectors. Other than that the truck runs really well!

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Have you gone for a long drive or go over any hills with the Amazon thermostat installed yet? Or was the 190deg temps taken just in park? I'm considering going the non oem thermostat route too. Please keep us updated after a few weeks use of the new thermostat.
 
Have you gone for a long drive or go over any hills with the Amazon thermostat installed yet? Or was the 190deg temps taken just in park? I'm considering going the non oem thermostat route too. Please keep us updated after a few weeks use of the new thermostat.
Have not done any hills or mid day traffic. But the other thermostat would never go this low. Not even if it was raining and 70F out. It basically was at 203 all the time until it climbed up to 217F
 
@Wagoncruzer I had a new OEM thermostat several years ago that had similar symptoms. Put the old one (which had only been in for a few years previously) back in and temps went back to normal. Last year when I did my t-belt and WP service, I put another new OEM thermostat in and had no issues.
 
@94SRUNNER I would definitely prefer OEM as that is what I most always go with when getting replacement parts. I would try another or get a lower temp OEM. I heard there were different temps available but couldn’t find it. Even the standard one would be fine if it stays at 195F.
 

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