Am I running hot?

[GT400]

So i cant figure this car out... I've got a mechanical water temp gauge, mounted in the plug in the thermostat housing. this should be the hottest point in the cooling system.

Around town the gauge reads anywhere from 190 - 210 degrees F. At highway speeds, it can reach near or just past 230. My dual fans come on at 185, and dont run unless im sitting. so the radiator is cooling, there does not seem to be any air in the system, and i've put a new radiator and Red Line Water Wetter in, both helped.

right after i installed the new radiator, i drove for about two hours on the interstate. it started off cool, and slowly heated up to about 230. i pulled over just to check for leaks, etc., and left the car idling. no leaks, got back in the car, pulled back into traffic, and realized i was running back at 195, where it stayed until i got off the interstate, at which point it heated back up.

So, whats goin on. Should i be concerned with the high temps? the car runs just fine, just seems high to me.

Sorry for the long post, but im stumped.

Daniel

 

[bansheebuzz]

230 = 110 deg celsius. Thats too hot, mine runs 80 - 85 (176-185)on the highway in the middle of the day

 

[rms]

The thermostat housing is water into the engine from the bottom of the radiator and incorporates a bypass system.

The other outlet without the thermostat is where the temp sensor must go.

 

[GT400]

well, i cant argue because im not sure, but this would be the only vehicle im familiar with in which the thermostat is the inlet. The thermostat is used to regulate engine temp. it open when it gets hot enough to let water flow into the radiator, at least in most vehicles...

and if im running 230F at the inlet, something is very wrong.

 

[rms]

well, i cant argue because im not sure, but this would be the only vehicle im familiar with in which the thermostat is the inlet. The thermostat is used to regulate engine temp. it open when it gets hot enough to let water flow into the radiator, at least in most vehicles...

and if im running 230F at the inlet, something is very wrong.

Toyota run the thermostat on water into the engine as do a lot of Japanese engines. Where you have the sensor is a bleed point and traps steam/air.

Just use a simple test. Which hose is the hottest ? Which hose goes to the top of the radiator ? That is water out of the engine and where the sensor must go.

 

[mshawari1]

I have the same problem … I change the radiator and the fans … but still the same ..
I am thinking … may be the water pump dose not flow enough !!!
Because
- I get more hot while I am running fast on high way .
- in the previous motor (same = 1UZ) the temperature never go at that limit with bad radiator. ​

 

[cjsupra90]

Daniel, You you do have the lower radiator hose going to the thermostat housing and the upper hose on the connection that is part of the cross over bridge, correct?

Second thing is what T-stat are you running? Try a new one from a lexus dealer and lastly, try installing the temp bulb for the gauge into the cross over bridge some where by drilling and tapping where the original temp sensor goes. This is where Toyota / lexus reads from and thus probably the best location.

 

[GT400]

Okay, i think i figured part of it out. I pulled the bra off the front of the car, and it runs quite a bit cooler. I doesnt go past 210 on a 105 degree day now, even sitting in traffic.

 

[cjsupra90]

another thing is, do you have the underside cover still on the car? If not, that will cause issues too. You atleast need the section that goes from then bumper cover to the radiator core support, the rest of it that goes past the core support under the engine is not need and IMHO, is actually bad to have on from a cooling standpoint. Yes, it is called a splash pan and does help to keep water from being spashed up on the engine, but at the same time, it help trap heat in the engine bay.

I did a little testing a few years ago by monitoring temps (coolent and intake air temps) with and without the entire splash pan and with the rear section (core support back cut off).

Test conditions were 95* F and road speed of 80mph over a 10 mile distance.

With the entire splash pan (as per stock setup)
coolent temp stable @ 185* F
Intake temp stable @ 110* F

With splash pan totally removed
Coolent temp stable @ 200*F
Intake temp stable @ 108*F

With splash pan installed but rear section cut off behind core support
Coolent temp stable @ 185*F
intake temp stable @ 99*F

 

[GT400]

i made a new plate to go in there a while back because i didnt have one. it helped quite a bit.