2UZ-FE Normal Operating Temperature (1 Viewer)

94SRUNNER

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Oct 9, 2006
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Dayton, OH
 
 
Found this new Aluminum option. Who's going to be an early adopter test pilot......

I've heard good things about Mishimoto. I was encouraged to see that they actually show one installed in a 100.

Thoughts on the higher psi rad cap?
 

abuck99

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Nov 8, 2015
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ATL
 
I've heard good things about Mishimoto. I was encouraged to see that they actually show one installed in a 100.

Thoughts on the higher psi rad cap?
Haven't run the higher PSI cap- these trucks run fairly cool compared to higher performance engines so I'm not sure what if any measurable improvement we would see. To me the consideration of welded aluminum tanks over crimped on plastic tanks is the longevity factor. Might possibly be the last radiator you need to buy.
 

94SRUNNER

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Oct 9, 2006
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Dayton, OH
 
 
Haven't run the higher PSI cap- these trucks run fairly cool compared to higher performance engines so I'm not sure what if any measurable improvement we would see. To me the consideration of welded aluminum tanks over crimped on plastic tanks is the longevity factor. Might possibly be the last radiator you need to buy.
Not to get away from the original scope of the this thread, but I reached out to Mishimoto to ask if the radiator was compatible with the OEM cap. They do not show that the OEM cap is compatible with their radiator. Anyone have any thoughts on this or if it should be a concern that the OEM cap may not be compatible?
 

Nightbrew

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Jan 20, 2013
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Missouri
 
That would be great. But the more I think about this the more I think about how many 100 series drivers are out there just happily tooling about in their ignorant bliss and the ECT temps go up and down but they never know any better because it's not moving the needle and while it might be running hotter than a new truck it's still not in the danger zone.
Ok I am have been back on the roadways but rather limited. Summer temps are gone but I have done a small amount of driving with oat in the upper 70’s low 80’s. I am seeing better numbers on the ultragauge. Other than longer slight grades, I am seeing 186 just about everywhere. On the longer slight grades I have seen 190. It is better than before and I feel better so far. I am awaiting summer temps, for the true test.
 
Joined
Nov 4, 2007
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10,109
Location
Colorado
 
 
Here's some 07LC w/133k heavy built (King coils w/30mm spacers, Iron bumpers, winch, compressor, rear lockers, rack, sliders, drawer, 5 Ko2's) ECT FT IAT numbers.

176-186F OAT 70F sunny 3PM. Test drive, (IN).
154-174F OAT 41F over cast noon. Test drive after topping coolant.
189-196F OAT 36F sunny 2PM. Test drive after thermostat (OUT).

This one came to for AHC Globe R&R and adjusting sensors & T-bars. I took a short test drive, and notice ECT was only running low around 176 - 186F. That was second drive in which first lower. It took unusually long to reach these temps. First drive 5 miles in slow speed of 25-35 MPH. I ran in low gear at times running RPM up ~4K. Shut it down and drove again before hitting ECT 184F. The OAT was ~70F and sunny.
176-186F OAT 70F sunny. Test drive in.

I found coolant low, I add total of 2 qts to radiator and reservoir. Then took another test drive making multiple stop over 30 miles on another day. Seeing:
154-174F OAT 41F over cast. Test drive after topping coolant.

R&R OEM thermostat, Cap and clogged air filter. Took another drive. I'll note the radiator finds where and are clogged. OAT was to cold to for wet work of clean at this time. But on the heels of winter, not a big concern. On this drive I hit the HWY and did a burnout run. I ran at 5.2K RPM for 5 minutes at 60MPH (geared DN). ECT was steady at 196F. Once I dropped RPM down to ~3K taking speed up 75MPH in "D". The ECT jumped too 201F for 3 seconds then drop back to 196F quickly. Coming off HWY speeds dropping the temps drop more 189-194F.
189-196 OAT 36F sunny 2PM. Test drive after thermostat.

Although radiator fins dirty on all test drive. It seem to support the VVT engine does run hotter normally. The higher OAT temp on first day (IN), did yield higher ECT but below normal op temp of any year 100 series I've seen I'll do more work some warm day cleaning radiator and tuning engine. But considering the cooler OAT temps, dirty radiator fins less effect than a hot sunny day.

BTW I found thermostat jiggle valve more than ~12 degrees, from top. Which is within limit, but I shoot for 5 degrees. The thermostat blew it's inner seal. Cust., report 1 incident of fuel boiling in the mountains. Likely it overheated. Gas cap area was relatively clean. Likely due to air in coolant system, from improper topping.
IMG_9319.JPEG

IMG_9320.JPEG
 
Last edited:
Joined
Feb 29, 2020
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67
Location
NV
I would like to provide some cooling input.

Finally completed the final part of the baseline of my 98 LC. The Radiator....

Original radiator @ 170k right when I was experiencing really high temps. Highest I've felt was 215. For sure on its last leg with that top tank browning and with hairline cracking.



Pulled the trigger on a Koyorad and quality was superbe imo, and priced way better than Denso. Installed with brand new OEM Toyota radiator cap. Flushed system and refilled with Toyota red super long life coolant.





Now im experiencing normal operating temperatures. 182-184 occasional 186 in the morning heading to work @ 70-80 degrees. 188 afternoon temperatures heading home in 90 degree weather with occasional 190 at idle at the stop light with AC on.

Did this about a month ago and no leaks. I'm happy.
 
Joined
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Messages
10,109
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Just did another VVT, 06LX very clean:

Radiator fins dirty:
ECT 196-201 OAT 70F Short dr
ECT 196-201 OAT 54F Long dr

After Radiator fins washed (1st wash)
ECT 192-196F OAT 54F short dr.

Seems the VVT does run hotter than non VVT. The difference I see in mechicals is fan and fan clutch. Thermostat, although different PN #, has same appearance and temp (82C).
 
Joined
Nov 4, 2007
Messages
10,109
Location
Colorado
 
 
I would like to provide some cooling input.

Finally completed the final part of the baseline of my 98 LC. The Radiator....

Original radiator @ 170k right when I was experiencing really high temps. Highest I've felt was 215. For sure on its last leg with that top tank browning and with hairline cracking.



Pulled the trigger on a Koyorad and quality was superbe imo, and priced way better than Denso. Installed with brand new OEM Toyota radiator cap. Flushed system and refilled with Toyota red super long life coolant.





Now im experiencing normal operating temperatures. 182-184 occasional 186 in the morning heading to work @ 70-80 degrees. 188 afternoon temperatures heading home in 90 degree weather with occasional 190 at idle at the stop light with AC on.

Did this about a month ago and no leaks. I'm happy.
Can you post a picture of old radiator fins front side. Bet it's fins or dirty )clogged).
 
Joined
Jul 3, 2015
Messages
91
Location
Mesa, AZ
 
Alright, I know its been hot here in Vegas at 112 today but I've noticed my temperature hitting 215-218 on the scangauge with my AC on while I was in the drive thru today, which is getting me worried. But while driving, I eventually get back down to 188/190

I have done the following PM work with all brand new Toyota OEM parts within the past 3 months.
-WP & TB
-Thermostat
-Crank Seal
-Upper and lower radiator hoses
-Refilled system with fresh Toyota Red long life coolant

What I haven't done is change the radiator, which is still original and I'm currently at 170k. Clutch fan engages and stays rotating when engine is on.

Anyone have an idea why I'm hitting over 200? Maybe its time for a new radiator? Thermostat rotation placement?

Any feedback would be appreciated! Thanks in advanced!
I chased a similar problem for years. Check to see if it holds pressure. The smallest leak will cause that. I added Phil’s aux fan kit to my 05. Yours might have one already. Didn’t fix it. Finally changed the condenser due to a leak and it seems to be fixed. I’m in AZ.
The theory is that the condenser was getting crazy hot and heating the radiator. If I turned my ac off when temp was at 220 or so, it dropped like a brick. Turned it back on and it soared back up.
 
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Apr 18, 2019
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Farmington, NM
I'm curious if the engine cover has any impact on cooling at speed, Does anyone have any comparison with it on vs. off? a discussion on GXOR made me start thinking about this as I took it off within a couple weeks of purchase.
 
Joined
Nov 4, 2007
Messages
10,109
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I chased a similar problem for years. Check to see if it holds pressure. The smallest leak will cause that. I added Phil’s aux fan kit to my 05. Yours might have one already. Didn’t fix it. Finally changed the condenser due to a leak and it seems to be fixed. I’m in AZ.
The theory is that the condenser was getting crazy hot and heating the radiator. If I turned my ac off when temp was at 220 or so, it dropped like a brick. Turned it back on and it soared back up.
Interesting "condenser". Can I ask:

Was AC blow cold?
Did you take actual temp readings at cabin HVAC vent?
Where you losing pressure in AC system?
Do you have any picture of the condenser and or radiator?

I ask because, condenser unusually hot, could transfer heat to engine radiator to some extent. But if condenser leaks, pressure drops in AC system, and compressor will not run. So condenser would just be OAT. Turning AC on would have almost no effect, except HP draw for blower fan electric use.

It's much more likely, the condenser along with other two radiators fins dirty (clogged)

I'm curious if the engine cover has any impact on cooling at speed, Does anyone have any comparison with it on vs. off? a discussion on GXOR made me start thinking about this as I took it off within a couple weeks of purchase.
I've done testing in the 98-02. I saw no difference in ECT with #1, #2 undershield and engine valley covers off or on.

The foam on side and top of radiator may help. That foam helps direct air flow with great pressure into radiators fins. The lower foam would also help when all foam in.
 
Joined
Jul 3, 2015
Messages
91
Location
Mesa, AZ
 
Interesting "condenser". Can I ask:

Was AC blow cold?
Did you take actual temp readings at cabin HVAC vent?
Where you losing pressure in AC system?
Do you have any picture of the condenser and or radiator?

I ask because, condenser unusually hot, could transfer heat to engine radiator to some extent. But if condenser leaks, pressure drops in AC system, and compressor will not run. So condenser would just be OAT. Turning AC on would have almost no effect, except HP draw for blower fan electric use.

It's much more likely, the condenser along with other two radiators fins dirty (clogged)


I've done testing in the 98-02. I saw no difference in ECT with #1, #2 undershield and engine valley covers off or on.

The foam on side and top of radiator may help. That foam helps direct air flow with great pressure into radiators fins. The lower foam would also help when all foam in.
The condenser was a theory at first. I work in service at a dealership so I was bouncing it off of everyone. Replaced EVERYTHING coolant related. Nothing worked. Adding the Aux fan kit slowed the temp from rising but still rose.
my foreman thought maybe the condenser was causing it because it only occurred with Ac on and dropped so fast without.
finally, my rear ac was warmer than usual. Had a tech find a seam leak in the condenser. Pulled it out and found that is was a used part. Junkyard writing on it. the assumption it that it was oil soaked. After replacement, no issues. May not be the fix but no issues over the last 2 summers.
 
Joined
Apr 18, 2019
Messages
603
Location
Farmington, NM
Interesting "condenser". Can I ask:

Was AC blow cold?
Did you take actual temp readings at cabin HVAC vent?
Where you losing pressure in AC system?
Do you have any picture of the condenser and or radiator?

I ask because, condenser unusually hot, could transfer heat to engine radiator to some extent. But if condenser leaks, pressure drops in AC system, and compressor will not run. So condenser would just be OAT. Turning AC on would have almost no effect, except HP draw for blower fan electric use.

It's much more likely, the condenser along with other two radiators fins dirty (clogged)


I've done testing in the 98-02. I saw no difference in ECT with #1, #2 undershield and engine valley covers off or on.

The foam on side and top of radiator may help. That foam helps direct air flow with great pressure into radiators fins. The lower foam would also help when all foam in.
Awesome, Thanks.
 
Joined
May 20, 2019
Messages
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Location
Las Vegas NV
Sharing for a 2UZFE VVTi after 90k mile service.
3A0B862A-1987-4C63-A5E2-2D8211532103.jpeg

86°C or 186.8°F operating temps on outside temps of 72°F (highest) and 70°F (lowest) with 5% Las Vegas air humidity.
• new oem thermostat & thermostat gasket
• new water pump, aisin
• new water pump gasket, oem
• new water pipe o-ring gaskets, oem
• new fan clutch, aisin
• new fan clutch bracket, aisin
• new pulleys and v-belt, aisins/continental
• new 3.4 gallon coolant, oem
• new rad hoses 1&2, oem
• new engine oil and oil filter, 0W16/oem

Planning to change the rad cap soon just to make sure cooling system is venting correctly per spec. Did not change the radiator it seems to be in good condition still a few dings here and there but no leak.

I haven’t used the AC yet, but I will share soon the temps when front and rear AC is on and hopefully with the new rad cap installed as well.

Fwiw my ect prior to the service was 92°C on the exact same internal and external conditions.
 
Last edited:
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May 27, 2019
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Location
Denver
Re: AC discussion. Purely anecdotal evidence gathered while sitting in the carpool lane waiting for my kids.

My '06 would reach the 210 range while idling for several minutes in ~100 degree air temps. If I would turn off the AC and shift into neutral, it would sit at 190 all day long. AC on and trans in neutral, I would get to low 200s. AC off and in D, it would creep back into the low 200s. Now that the air temp is cool, 190 all the time even in D and no AC.

If everything in the cooling system is not working perfectly, the slight AC strain may impact temps and the higher RPMs while in Neutral spin the fan faster creating more air flow. While this isn't fixing anything, it may help relieve some stress while sitting in traffic next summer watching the engine temp rise.
 
Joined
Feb 20, 2019
Messages
171
Location
Minneapolis, MN
Changed my thermostat and radiator cap, -7°C on the highway and -9°C idling. Highway is 83°C and idling is now 85°C with OAT of 21°C I suspect my radiator cap wasn't holding pressure properly, although it wasn't leaking coolant. I used to not hear any pressure release when opening the radiator cap when the engine was mildly warm ~50°C. Tried it again after replacement and heard an audible hiss.
 

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