2UZ-FE Normal Operating Temperature (1 Viewer)

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So this might be a stupid question but how much do the bottom skid plates impact engine temps? I took mine off a few months ago and haven't put them back on yet. I'm still monitoring my temps after installing the new thermostat but I just wonder if temps will go up a bunch when I put the plates back on.
I don't think stock skid make much difference in the summer. I've two 98-02 pure stock I recently service coolant system in.
  • CSF radiator with side & top foam, no undershield on: 184-187F w/OAT 97F sunny mid day.
  • Factory radiator foam on all four side, all under shield on. 184-187F w/OAT 97F sunny mid day.

Replaced the fan clutch last year. Everything checks out with it. I'm beginning to wonder if my Slee skid plate combined with the winch is the cause of the higher temps. What's weird though is that the temps rise with the RPM. If I just idle, I'll sit around 193 (still high). Anything over 65 and I'm 198+. I rinsed the radiator and trans cooler out with distilled water. The fins all look clear.

Wondering if the serpentine belt might have something to do with it? It's 3 years old, but wondering if maybe it's slipping. It seems plenty tight though.
Oh, my understanding was engine temp up after overheating. Was this Slee stuff added, than running hot started?

If you serp belt is OEM and did not start and keep chirping after getting wet from washer radiator, it's likely fine. Tensioner can be check just by put a 14mm socket on ratchet. It should have good back pressure.
 

geanes

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I don't think stock skid make much difference in the summer. I've two 98-02 pure stock I recently service coolant system in.
  • CSF radiator with side & top foam, no undershield on: 184-187F w/OAT 97F sunny mid day.
  • Factory radiator foam on all four side, all under shield on. 184-187F w/OAT 97F sunny mid day.

Oh, my understanding was engine temp up after overheating. Was this Slee stuff added, than running hot started?

If you serp belt is OEM and did not start and keep chirping after getting wet from washer radiator, it's likely fine. Tensioner can be check just by put a 14mm socket on ratchet. It should have good back pressure.
The engine running hot started prior to the Slee skid. It started getting over 188 periodically after the overheat incident. Dealer claimed they replaced the t-stat and refilled coolant. It would hold 188 most of the time, but would kick up to 191-193 under any kind of load. It started running consistently hot around late May....about 2 months after the CSF installed. The CSF never seemed to let the truck stay below 190 while driving at all though. I'm wondering if the CSF is somehow at fault. There are no bent fins though. It's so odd. Feel like I'm chasing my tail trying to identify why it's been running hotter than what I had seen for 3 years prior.
 
Joined
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A few thoughts:

  • New OEM radiator cap with new radiator, always. Yeah, I went CSF based on positive recommendations. I did not transfer any of the foam. I added foam along the topline though.
Foam may make a difference. Jury still out.

  • Make sure all three (engine coolant rad, condenser and oil cooler) radiators fins are clean. Rinsed out all 3 several times over the past few months using "spotless" rinse at a local carwash on very low pressure. Considering spraying some of that foaming condenser cleaner in there, letting sit for 20 seconds and rinsing away. Heard very good things about Koil Klean I believe it's called.
Make sure to rinse from below skids off and from inside out. I 've found during installs spend two hours cleaning all three, I still have to vacuum and blow out. I'd wash with more HP water, but in shop during install.
  • Watch your fuel trims. Short term running lean (-) may indicate vacuum leak or weak or poor fuel injector spray. I've never monitored these. Something I can program into Scangauge I assume. What would I be looking for r.e. "lean" vs "rich"?
Short term fuel trims are what engine is doing at the moment, which EUC controls by injector fuel injector pulse. Long term fuel terms are what ECU is doing to correct, setting a new base line. This is while idling or stead on throttle. Reads when throttling or letting off throttle, are meaningless for this exercise. More air than fuel is lean condition, from what is optimal of 14.7 air to 1 fuel. When engine runs lean cylinder head temps rise. In small propeller airplanes, they have a cylinder head temp gauge, and a mixture control. It's import to keep adjusting as air desty changes. Old cars with carburetor have issues driving to different part of the country. Reason is the air fuel mixture is set by size of fuel jets. Modern cars have fuel injectors, 02 & A/F sensor and ECU to keep mixture optimal at 14.7 to 1. But if engine has say a vacuum leak, too much air enters combustion chamber through intake. EUC can get over worked trying to keep up. This is a lean condition. Also if fuel resticked or pressure low, again we've a lean condition.

Engine run rich runs cool.

Here a short bit on fuel trim. Google and you'll find tons of info.


  • Try spinning fan cold. After a few turns it should loosen up. It can also be stopped with a rolled up newspaper, during warmup. After warm up, as fan clutch gets hot, it will make a loud fan (turbo) sound. Than it can't be stopped by a rolled up paper. With the engine off, I can spin the fan about 1/4 turn before it stops.
Also be aware we two different fan clutches. 06-07 is large with different fan. Older clutch will not fit on newer fan. But seem the new clutch will fit on old.
  • Any change in oil pressure since 260F overheat. Haven't actually checked that other than the useless Toyota gauge in the dash. Nothing abnormal on it though. It sits right in the middle while driving and drops to low at idle just as it always has. I assume the Scangauge has a code I can input to view the oil pressure. Not sure what numbers constitute good vs bad though.
Dash gauge the same or about same, tells me, oil pressure not likely dropped. So bearing and oil pump are okay.

If you get up to Denver stop in.. I can take a look! I will definitely hit you up when I get back up to Denver. I'll bring some gifts from Texas for ya :)

Gifts. Very kind of you, but no need.
 
Joined
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The engine running hot started prior to the Slee skid. It started getting over 188 periodically after the overheat incident. Dealer claimed they replaced the t-stat and refilled coolant. It would hold 188 most of the time, but would kick up to 191-193 under any kind of load. It started running consistently hot around late May....about 2 months after the CSF installed. The CSF never seemed to let the truck stay below 190 while driving at all though. I'm wondering if the CSF is somehow at fault. There are no bent fins though. It's so odd. Feel like I'm chasing my tail trying to identify why it's been running hotter than what I had seen for 3 years prior.
So after May, which is when OAT was on up swing.

Keep in mind you are a heavy with skids, which well run hotter. I feel @abuck99 is good example of a heavy's ECT range. But he has and 05. I'm still trying to get stock base line for 03-05 and 06-07. But the 98-02, in the miles high city, is for sure 184 to 187F. I've repeated those ECT in stock after coolant service and tune, time and time again..

If your temp come back down this winter. Than likely this is not overheating damage.
 

MJK

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If you get up to Denver stop in.. I can take a look! I will definitely hit you up when I get back up to Denver. I'll bring some gifts from Texas for ya :)

Gifts. Very kind of you, but no need.
Are you turning down Texas Brisket?
Is this a cry for help?
Do you need medical attention or something?

Post 3 pieces of blatantly incorrect information if you are being held against your will.
 

abuck99

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Lots of opinions offered - here’s another....

1. Check your compression and leak down.
2. $200 for a Denso radiator- try a different rad and see if you have a better result. New oem cap and new oem thermostat & fresh coolant.
 
Joined
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Messages
10,113
Location
Colorado
 
 
Are you turning down Texas Brisket?
Is this a cry for help?
Do you need medical attention or something?

Post 3 pieces of blatantly incorrect information if you are being held against your will.

Texas brisket. OMG, bring it on, ship it in, fly it in whatever it take just get it here.;)
 

MJK

Joined
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Messages
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Location
Tucson
Texas brisket. OMG, bring it on, ship it in, fly it in whatever it take just get it here.;)
Excellent, that is the spirit! Glad to hear you are well!

There is very little that cannot be solved in the afterglow of warm Texas brisket and a nice cold beer.
 

Lonegrasshopper

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Hmmm...Cool thread! Okay, I took a trip these past two weeks from DFW to NM and AZ, around the Gila USNF, and I have some numbers. Most of my trip, HWY doing about 80ish mph, I saw engine temps constant around 188F, and trans around 160F. BUT...on some intense climbs, like 1k feet gain in a mile or so doing 80ish, I saw the numbers spike. Oh! Local temps were pushing 100F, yes, in the end of September southern AZ and NM can see 100F. Okay, during these climbs I saw my engine temp reach 200F, got a bit concerned, and my trans hit 180F. I also had a pretty good load with camping gear, and my LX is more or less stock. No additional armor. Now after seeing your posts I feel good.

I am thinking of doing a small write-up on how the AHC preformed on the trip with the different types of roads. Short story, loved it, and took some advise from @suprarx7nut, and expanded on it.
IMG_5019.JPG
 

ramangain

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Hmmm...Cool thread! Okay, I took a trip these past two weeks from DFW to NM and AZ, around the Gila USNF, and I have some numbers. Most of my trip, HWY doing about 80ish mph, I saw engine temps constant around 188F, and trans around 160F. BUT...on some intense climbs, like 1k feet gain in a mile or so doing 80ish, I saw the numbers spike. Oh! Local temps were pushing 100F, yes, in the end of September southern AZ and NM can see 100F. Okay, during these climbs I saw my engine temp reach 200F, got a bit concerned, and my trans hit 180F. I also had a pretty good load with camping gear, and my LX is more or less stock. No additional armor. Now after seeing your posts I feel good.
Baby temps on the incline, you're good. Try towing up the Shasta pass into Oregon towing 7000+ lbs of trailer, then let's compare. I was SHOCKED I never had to stop to let stuff cool down.

My s*** always works sometimes!
 

Lonegrasshopper

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Baby temps on the incline, you're good. Try towing up the Shasta pass into Oregon towing 7000+ lbs of trailer, then let's compare. I was SHOCKED I never had to stop to let stuff cool down.

My s*** always works sometimes!
You know? I never driven up that pass in a LC. I drove down it in my '83 FJ60 from Portland towing a trailer, up and down it in my 2007 FJ Cruiser, but never up it in a true Cruiser towing. I've had to drive up I-5 like a bat out of Hell one winter in a Saturn PoS to be in front of a winter storm before the interstate got closed one time. That pass sucks.

Don't ask the time frames, they are long, and I have lived in multiple states, some more than once.
 
Joined
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Messages
10,113
Location
Colorado
 
 
Hmmm...Cool thread! Okay, I took a trip these past two weeks from DFW to NM and AZ, around the Gila USNF, and I have some numbers. Most of my trip, HWY doing about 80ish mph, I saw engine temps constant around 188F, and trans around 160F. BUT...on some intense climbs, like 1k feet gain in a mile or so doing 80ish, I saw the numbers spike. Oh! Local temps were pushing 100F, yes, in the end of September southern AZ and NM can see 100F. Okay, during these climbs I saw my engine temp reach 200F, got a bit concerned, and my trans hit 180F. I also had a pretty good load with camping gear, and my LX is more or less stock. No additional armor. Now after seeing your posts I feel good.

I am thinking of doing a small write-up on how the AHC preformed on the trip with the different types of roads. Short story, loved it, and took some advise from @suprarx7nut, and expanded on it.View attachment 2446580
Great info. THX!
07 running at 188 ECT w/OAT of 100F as baseline, on HWY at 80MPH. Is kind of data/info I'm looking for.

More detail on rigs service history, would also be helpful.

Like if and when:
Coolant service done, what included like radiator fin cleaning, etc.
Milage.
Tuneup with vacuum lines, coils, spark plugs serviced.
Transmission level set to new Toyota recommendation.
etc..
 

Lonegrasshopper

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Messages
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Great info. THX!
07 running at 188 ECT w/OAT of 100F as baseline, on HWY at 80MPH. Is kind of data/info I'm looking for.

More detail on rigs service history, would also be helpful.

Like if and when:
Coolant service done, what included like radiator fin cleaning, etc.
Milage.
Tuneup with vacuum lines, coils, spark plugs serviced.
Transmission level set to new Toyota recommendation.
etc..
Bought the rig last November with 186k miles on it. Replaced the heater T's a month later in December, radiator went tits up in March and replaced it with a Denso off Amazon. Mr. T did a complete flush of the transmission fluid I think in either May or June of this year, and also had them do the t-belt service in June at 190k miles. Records show the plugs were done at 120k miles. I replaced the PCV this month just before my trip. So I suppose with me replacing the radiator in March and Mr. T doing the t-belt in June we can say my coolant system is well flushed. All other fluids have been base lined by me since owning it this year, oh, except I had Mr. T do the brake flush since I did not have that expensive tool for the ABS. Right now the rig has 196k miles.

I like saying Mr. T.
 

Lonegrasshopper

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I spent my pre-teen years in Tucson in the 80s! Lived north of river rd between 1st and campbell.. MAN that area changed along river rd since the 80s
I spent my pre-teen years in Tucson in the 80s! Lived north of river rd between 1st and campbell.. MAN that area changed along river rd since the 80s
I was just east of you, basically Sabino Canyon. Snyder and N Kolb. I took River Rd into work every morning in my FJ60 to my parts job at Precision Toyota. So, yeah, I drove clear across town in a Cruiser.
 
Joined
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Location
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Bought the rig last November with 186k miles on it. Replaced the heater T's a month later in December, radiator went tits up in March and replaced it with a Denso off Amazon. Mr. T did a complete flush of the transmission fluid I think in either May or June of this year, and also had them do the t-belt service in June at 190k miles. Records show the plugs were done at 120k miles. I replaced the PCV this month just before my trip. So I suppose with me replacing the radiator in March and Mr. T doing the t-belt in June we can say my coolant system is well flushed. All other fluids have been base lined by me since owning it this year, oh, except I had Mr. T do the brake flush since I did not have that expensive tool for the ABS. Right now the rig has 196k miles.

***
Hmmm...Cool thread! Okay, I took a trip these past two weeks from DFW to NM and AZ, around the Gila USNF, and I have some numbers. Most of my trip, HWY doing about 80ish mph, I saw engine temps constant around 188F, and trans around 160F. BUT...on some intense climbs, like 1k feet gain in a mile or so doing 80ish, I saw the numbers spike. Oh! Local temps were pushing 100F, yes, in the end of September southern AZ and NM can see 100F. Okay, during these climbs I saw my engine temp reach 200F, got a bit concerned, and my trans hit 180F. I also had a pretty good load with camping gear, and my LX is more or less stock. No additional armor. Now after seeing your posts I feel good.
Thanks.
That is very good info. 188F is a good number. Jump to 200f on HWY ascent, seems a little high. But that is what I'm after. To find out what is normal for the VVT 06-07. that and the 03-05. I know the 98-02 is 184-187F all day long. Seem the VVT engine has been set up little different. For one has different fan and fan clutch.

I'd suggest to make sure a few things done or do:
Make sure your spark plugs are tight, they walking out.
Make sure your coolant is topped properly. By checking under radiator cap after 8 hour cool down, front end higher than rear
Make sure all 3 radiators, fins are clean of road debris (bugs, cotten, grass, weds, feather, etc.)
Look for vacuum leaks (crack or loose fitting vacuum lines, including idle up control coming from vane pump).
If a new thermostat and radiator was not installed with radiator, replace them with OEM.
Consider a new fan clutch, if yours is the factory installed. 200K is getting up there.
Make sure your new radiator has foam on both side and top.

Be very interesting after all done or confirmed. How your temps run next summer. :hmm:
 
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West Coast
Thanks.
I know the 98-02 is 184-187F all day long.
Okay, so I just replaced my thermostat (and other things) and the temps aren't right, although my heater is blowing super hot now, which it wasn't before.

Driving around town right now with the OAT at about 60-70F (no heat and no AC) the ultra gauge shows 185F for a while, but it keeps creeping up to about 188 and then will spike at 190-192 for brief periods but then go back down to 188. But what I noticed that's weird is that when I come home, I am going about 25mph up a hill and then let off the gas, turn right, and then go down a hill. When I do this the temp jumps to 192 almost immediately. VIDEO but then cools back down to 188.

It does this EVERY SINGLE TIME. If it was 100F outside and I was blasting the AC I wouldn't be surprised by these numbers, but they seem hot given how cool it is outside. I also don't like the rapid fluctuations.

Here is what I did:

99 LX470
  • New OEM Thermostat (jiggle valve at the top)
  • New thermostat housing
  • New housing over the top of the thermostat
  • New serpentine belt
  • New PCV valve/hoses
  1. Refilled coolant and ran it until it warmed up, then shut down, added coolant to the overflow tank.
  2. The next morning I topped off the radiator then drove it to work. Parked on a slope. I did this three times. Each time I had to add a little coolant.
  3. Put one of those funnels to help bleed the air out, didn't really notice any bubbles coming out.
  4. Drove around a bit tonight and saw the same behavior. Parked on the steepest part of my driveway to check on it again tomorrow.
Getting a little frustrated...
 

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