High coolant temps (2 Viewers)

[Hoosier Daddy]

You say you checked the fan clutch audibly and visually. How about manually checking physical resistance in the clutch when hot?

I don't see any other stones you've left unturned. Seems that despite the harsh conditions, the truck got hot but it didn't get hot enough (yet) to cause any concern to the ECU or A/C. Perhaps you're still within the outermost boundaries of what is normal?

 

[Hoosier Daddy]

Oh, just a thought - how about the fan shroud and the foam insulation around the shroud?

 

[Onefastrx7turbo]

Here in AZ I usually run a 60/40 water/coolant ratio. 50/50 is not super critical here.

 

[hammerheadfistpunch]

Oh, just a thought - how about the fan shroud and the foam insulation around the shroud?

Foam shroud is my next check. I think its gone and from what I found on my 80, its actually super critical. if it is I will do like the 80 and...wait for it...Gaffer tape it. Serious, that stuff is great so long as its the high temp stuff. the glue shouldn't start giving up until well after 250f, its been solid for years.

 

[hammerheadfistpunch]

Here in AZ I usually run a 60/40 water/coolant ratio. 50/50 is not super critical here.

Its pretty cold here in Utah and this will be used up at bear lake in the winter which is regularly well below zero. So thats a no go.

 

[kbahus]

Belt stickr says replaced at 97k (115k now) done by a lexus dealer so without tearing into it its probably fine. Rad was replaced but they claim oe replacement.

That is a mighty big assumption, the dealer could have simply belt slapped it. The hydraulic tensioner is expensive and the PO could have gone the cheap route, which would leave you with a new belt, sticker, and nothing else (including the water pump). I would be trying to find some records on what exactly was done before assuming it has all been replaced and is all good. It should also be easy to confirm if the radiator is an oem unit by looking it over for a brand, place of manufacture, etc. Don't assume anything, no one in the auto industry is to be trusted in this day and age.

 

[langsen]

If the tstat is anything like it was in my 1st gen Tacoma it should be oriented with the jiggle valve in the 6 o'clock position. This was the difference of about ~15 deg (cooler @6 o'clock). I haven't done my due diligence on this engine yet. YMMV

The jiggle valve for the 2UZ-FE is supposed to be installed pointing straight up, plus or minus 30°.

 

[langsen]

Mine had the foam missing at the bottom of the radiator and it definitely made a difference when I replaced it, AC worked better too. I got some of the high heat pipe wrap and stuffed it in there.

What's the part number for the thermostat you used? I read somewhere that the 2UZFE has the thermostat after the radiator instead of before but I can't confirm it in the FSM. Seems like it would make a big difference in operating temp.

Mine is totally stock and runs at 195-205 around town here in Phoenix.

I've had a couple fan clutches that tested OK but still weren't working as well as they should have been. I would replace the fan clutch if nothing else helps.

 

[hammerheadfistpunch]

The jiggle valve for the 2UZ-FE is supposed to be installed pointing straight up, plus or minus 30°.

That's the beta I get straight from the guys at Toyota.

 

[lndshark]

Mine had the foam missing at the bottom of the radiator and it definitely made a difference when I replaced it, AC worked better too. I got some of the high heat pipe wrap and stuffed it in there.

What's the part number for the thermostat you used? I read somewhere that the 2UZFE has the thermostat after the radiator instead of before but I can't confirm it in the FSM. Seems like it would make a big difference in operating temp.

The thermostat is after the radiator (outlet side) as you mention. As for the jiggle valve, on any Toyota with a vertically-mounted thermostat, it should be mounted toward the 12 o'clock position (not just the UZ).

If you can see movement or flow of coolant in the radiator (cap removed, engine running), it's not likely to be the water pump. I'd bet more on what others have said (shroud, insulation, etc).

 

[JLee]

I've experienced one water pump failure - when it went, my temps shot way up in a matter of seconds. I highly doubt that to be the problem.

 

[Onefastrx7turbo]

I wonder what the variance limit is on the coolant temperature sensors? + or - 5 degrees maybe?

 

[hammerheadfistpunch]

UPDATE - Bled the system, and lots of air bubbles came out, I did it for a good 30 minutes and replaced the overflow with water wetter. There were no bubbles coming out so I called it good (turns out there is a new rad cap on there as well so thats not it). I towed a popup trailer and the family to capitol reef in the heat (90F) and wind over hill and dale and it was working hard to stay cool. fan clutch was on most of the time (seemed to come on in full at about 205, and turn off around 190). Got it up to 215 but thats it. Still way too hot for my tastes. Does someone have images of what the foam around the radiator is supposed to look like? I don't think I have any.

 

[Onefastrx7turbo]

FYI, I cleaned the truck this morning and noticed that none of my foam along the bottom of the radiator is present. I'll probably buy some of the stick on foam from Ace Hardware. I did this on my 80 with good results.

 

[NMBruce]

Does someone have images of what the foam around the radiator is supposed to look like? I don't think I have any.

interested to see what this looks like

 

[danthemanx07]

Sub'd. I will look under the hood of my 2005 tomorrow for this foam y'all are talking about if no one gets to it before me. Where is it supposed to be at?

 

[Onefastrx7turbo]

So I was towing about 3,000 lbs trailer this weekend up to Sedona. The I-17 is the highway that runs north from Phoenix and pulling the relatively steep hills with the AC on and roughly 105F ambient temps I was seeing 209-212 coolant temperatures, which was fine. Then we hit traffic. Sitting in drive with the AC on high and basically not moving, I watched the coolant temperature climb from 210, to 212....214....215.........216.. and I started getting worried so I shut the air off and held the rpms in neutral at 1500. The temps quickly dropped from 216 to 208 within 20 seconds or so. I never saw the temperature reach higher than 214 as long as I was moving.

Once we got home, that was a different story. I was dumping the tanks and I left the truck running in park with the AC on, same as before. I'm guessing ambient temps were 108F. I saw the coolant hit 218 and then 220 before I turned the AC off and again, ran the rpms at 1500. Just as before, the coolant temperatures quickly dropped down to roughly 203 within 15 seconds with the Ac off and the rpms at 1500. This was the 1st time I'd seen the coolant get that hot.

It runs fine on the freeway, never above 201 with the AC on. Even towing, the temperatures were manageable as long as the truck was moving. Sitting the with the AC on in the blazing heat seems to overwhelm the cooling system. The AC fan runs and the belt driven fan seems to be engaging, as it roars with higher temps with RPMs.

Perhaps a thermostat? Coolant appears to be factory Mr. T pink fluid.

 

[hammerheadfistpunch]

So I was towing about 3,000 lbs trailer this weekend up to Sedona. The I-17 is the highway that runs north from Phoenix and pulling the relatively steep hills with the AC on and roughly 105F ambient temps I was seeing 209-212 coolant temperatures, which was fine. Then we hit traffic. Sitting in drive with the AC on high and basically not moving, I watched the coolant temperature climb from 210, to 212....214....215.........216.. and I started getting worried so I shut the air off and held the rpms in neutral at 1500. The temps quickly dropped from 216 to 208 within 20 seconds or so. I never saw the temperature reach higher than 214 as long as I was moving.

Once we got home, that was a different story. I was dumping the tanks and I left the truck running in park with the AC on, same as before. I'm guessing ambient temps were 108F. I saw the coolant hit 218 and then 220 before I turned the AC off and again, ran the rpms at 1500. Just as before, the coolant temperatures quickly dropped down to roughly 203 within 15 seconds with the Ac off and the rpms at 1500. This was the 1st time I'd seen the coolant get that hot.

It runs fine on the freeway, never above 201 with the AC on. Even towing, the temperatures were manageable as long as the truck was moving. Sitting the with the AC on in the blazing heat seems to overwhelm the cooling system. The AC fan runs and the belt driven fan seems to be engaging, as it roars with higher temps with RPMs.

Perhaps a thermostat? Coolant appears to be factory Mr. T pink fluid.

You say the AC fan was kicking on? how many miles?

 

[Onefastrx7turbo]

Yes sir. The AC fan runs whenever the AC is on, and the truck has about 113K on it.

 

[hammerheadfistpunch]

Yes sir. The AC fan runs whenever the AC is on, and the truck has about 113K on it.

I can only speak to my experience but when my 80 series was getting hot it was usually at slow speeds, never at highway speeds and it turns out the radiator was pretty clogged. mine had over 240k on it at that point but the only thing that solved the problem with mine was a new radiator. the current running theory with mine is that the company I bought it from replaced the factory rad with a cheap 3rd party thats under capacity. Even with with a new t-stat and fresh fluid its still 201-206 on the freeway with no real load.