Engine temps when towing

Joined
Jul 17, 2018
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1,454
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LUGOFF, SC
Normally the rig runs 186F to 194F.
When towing my trailer ~2000pounds (guess) this weekend the temps went to 228 in traffic and ran around 210-215 on the highway at an ambient temp of 95F and rolling at 60-70 MPH.
At low speeds (low gear climbing forest roads) it would get to 223/224F at 75F ambient.
I'm pretty sure my fan clutch has finally given out, considering I towed two jeeps (separate trips) on a U-Haul duelly this spring from 2 hours away and the temp never went over 200F. I figured those loads at around 4500#.
NoYtWPKl.jpg

On my commute today (no trailer of course) temps were 186-194 just like normal.

I have 10K CTS oil on order and will change out the fan clutch fluid when it gets here.

My question.... should I also change out the fan? Given that its probably original, will the stress of the new oil creating additional air flow and RPMs on the blades possibly grenade the original poly fan?
 
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enox

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Mar 12, 2018
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Los Angeles, CA
In my experience no, I have 22k cst oil in mine and it's good, pulled it out today to swap with a new radiator. Blades still looked fine.

This is the second round of fluid I've put in my fan clutch.

First round is what came in it.

Second I bumped it up to 10k cst. (That was burned when I drained it after 18mo)

Recently swapped in the 22k cst oil.

I assume yours is cooked and just needs freshening up.
 
Joined
Nov 9, 2012
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11,647
Location
Olathe, KS, USA
Normally the rig runs 186F to 194F.
When towing my trailer ~2000pounds (guess) this weekend the temps went to 228 in traffic and ran around 210-215 on the highway at an ambient temp of 95F and rolling at 60-70 MPH.
At low speeds (low gear climbing forest roads) it would get to 223/224F at 75F ambient.
I'm pretty sure my fan clutch has finally given out, considering I towed two jeeps (separate trips) on a U-Haul duelly this spring from 2 hours away and the temp never went over 200F. I figured those loads at around 4500#.
NoYtWPKl.jpg

On my commute today (no trailer of course) temps were 186-194 just like normal.

I have 10K CTS oil on order and will change out the fan clutch fluid when it gets here.

My question.... should I also change out the fan? Given that its probably original, will the stress of the new oil creating additional air flow and RPMs on the blades possibly grenade the original poly fan?
I'm planning on changing my fan as well, just to to the cycles it's seen for 317K miles. If I averaged 45 MPH for all of those miles, then my engine probably ran at 2200 RPM average, that's 7044.5 hours x 60 minutes=422670 minutes of operation.

422670 x 2200 = 929,874,000 cycles.

Yeah, I think it's time.......

In my case, my fan clutch is leaking at the seal on the shaft, so I'm changing that unit for sure.
 

enox

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Mar 12, 2018
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954
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Los Angeles, CA
Because its not in this months or next months part's budget.
I solved that issue and bumped up the budget!

On a similar note...waiting to get more real world results and will post a thread when I finish, but here's a teaser...

My radiator was a denso unit. Note the channel opening size.
PXL_20210712_182409393.jpg


Currently switching to the tyc 1918 ... Note the channel size.

PXL_20210712_182446623.jpg


I'm thinking 🤔🤔 this is also gonna drop my engine temps by getting more flow..
 
Joined
Jul 17, 2018
Messages
1,454
Location
LUGOFF, SC
This is the second round of fluid I've put in my fan clutch.

First round is what came in it.

Second I bumped it up to 10k cst. (That was burned when I drained it after 18mo)
How long did the Toyota replacement fluid last?
Why was the 10K fluid burned in 18mo? That isn't "normal" is it?
Am I going to be adding this to the PM list?
 

enox

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Los Angeles, CA
How long did the Toyota replacement fluid last?
Why was the 10K fluid burned in 18mo? That isn't "normal" is it?
Am I going to be adding this to the PM list?
I only recently bumped it up to get more air, it was only then when I drained it did I notice it was the color of honey. Not the clear color which went in.

In an attemp to get the weight right, this is the 3rd summer I have changed and bumped up every time.
 
Joined
Jul 17, 2018
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LUGOFF, SC
I solved that issue and bumped up the budget!

In a foolish attempt to get the rig ready for an epic 2wk road trip to Maine and back (didn't happen at the last minute :mad: ) I spent the next three months of "budget".
Oh well, other than the fan clutch re-oil she's pretty well set for the foreseeable future; but then my crystal ball has always been a touch fuzzy.
 
Joined
Aug 26, 2009
Messages
5,932
Location
flat earth Midwest
Normally the rig runs 186F to 194F.
When towing my trailer ~2000pounds (guess) this weekend the temps went to 228 in traffic and ran around 210-215 on the highway at an ambient temp of 95F and rolling at 60-70 MPH.
At low speeds (low gear climbing forest roads) it would get to 223/224F at 75F ambient.
I'm pretty sure my fan clutch has finally given out, considering I towed two jeeps (separate trips) on a U-Haul duelly this spring from 2 hours away and the temp never went over 200F. I figured those loads at around 4500#.
SNIP
On my commute today (no trailer of course) temps were 186-194 just like normal.

I have 10K CTS oil on order and will change out the fan clutch fluid when it gets here.

My question.... should I also change out the fan? Given that its probably original, will the stress of the new oil creating additional air flow and RPMs on the blades possibly grenade the original poly fan?
The fans get brittle with age. They're OK until you dip into that stream crossing that's deep enough they start sucking water, then they break. At least one thread about that, maybe more. Fans are pretty cheap, too, so why take a chance if you have an OEM fan that's long past it's Best By date?

Yeah, more viscosity in the oil will help. I forget what mix I ended up with, but it was pushing 20k.

But if you're still on the OEM radiator, check it over for cool spots using an infrared thermometer. Remember that every 80 out there is pushing 25 or more years of age. When I was going through similar issues a couple of years ago I found mine with multiple cool areas after shutdown. This indicates internal clogging. I chose brass for my new radiator, but aluminum gives you better cooling, so if I have a do-over, it will be to AL.
 
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Sep 15, 2016
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838
Location
Chattanooga, TN
Nice jeep. What is that a CJ6? is there such a thing? I have a few flat fenders that I enjoy but I'm not an expert on what came after or what you've got on the trailer.

Also, agree w above and you are definitely running hot and sounds like a fan clutch issue. I'd check the timing on it (see what temps the ports open) as well and adjust if needed when apart but I'm not sure most folks do that.

For reference, we just finished a loaded road trip pulling a popup that's around 3k pounds. Temps were typically in the 195 to 210 range and I pushed her pretty hard with lots of 4k+ rpm driving, mountains, wind, etc. Wind resistance seems to really hurt these trucks and when I moved the roof-top box from the 80 to the popup roof my temps dropped noticeably and speed increased. Similarly when towing my topless m38 I have no issues while the hard-top 2a really drops the 80s top speed...
 
Joined
Dec 14, 2018
Messages
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Location
Silverthorne, CO
I solved that issue and bumped up the budget!

On a similar note...waiting to get more real world results and will post a thread when I finish, but here's a teaser...

My radiator was a denso unit. Note the channel opening size.
View attachment 2729702

Currently switching to the tyc 1918 ... Note the channel size.

View attachment 2729703

I'm thinking 🤔🤔 this is also gonna drop my engine temps by getting more flow..
Let me know how your tyc does. I recently swapped to one and it seems like the radiator cap neck is too tall. It prevented both relatively new oem caps I had from sealing. The dualast cap I got at autozone works.

I
 

enox

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Mar 12, 2018
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Los Angeles, CA
Let me know how your tyc does. I recently swapped to one and it seems like the radiator cap neck is too tall. It prevented both relatively new oem caps I had from sealing. The dualast cap I got at autozone works.

I
Interesting point...didn't think that would be an issue. I'll be wrapping it up today and using the OEM cap. Will let you know.
 
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Silverthorne, CO
Interesting point...didn't think that would be an issue. I'll be wrapping it up today and using the OEM cap. Will let you know.

I didn't either.

I have also been in a 3 year battle to get my cooling system clean. This Spring was the 3rd time I have done a complete flush in 3 years. I have a feeling there was a red / green coolant mix in the vehicles past based on the amount of brown crud that was in the system. I had a bit of a scare when I hit 220 heading up a pass here in Colorado and finally did another overhaul.

Turned out my fan clutch was not only toast, but had been replaced with a cheap O'Rielys unit at some point in its past. You don't read too much about the US made "brown hub" because it sucks!

I went with a new TYC radiator and an unmodded blue hub clutch. Before I swapped the radiator I flushed the system again and ran nothing but distilled water for 5 days, changing it out each morning. After day 5 it was finally only a very light tan color and I went back to regular green coolant. Since then my temps have been drastically improved and the coolant is holding its color (used to turn brown in a week after replacement).

I am now dealing with an issue where the radiator cap will occasionally not fully seal which prevents the cooling system from pressurizing. This causes slightly higher temps but the main concern I have is the "afterboil" when the engine is shutoff. When the system is not pressurized the coolant inside the head gets hot enough to boil for a few seconds after shutdown. I have this issue with both of my OEM rad caps (less than 1 year old) but not with the Duralast unit.

I really want to try sanding down the radiator cap neck a mm or two but need to verify that is my issue first. I am assuming the cap tolerance is pretty tight so a mm too tall or too short could cause issues.
 
Joined
Feb 28, 2012
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N. Phx
Same issue with TYC1918 radiator cap neck and OEM Toyota radiator cap. I found that the cap doesn't seal nearly as well as on a Toyota Radiator, so was getting the shut-down boiling sounds from the radiator, with occasional burping of a cup or two of coolant out of the overflow bottle.

I traced this back to air bubbles in the system after a coolant fill from empty, and its since subsided from burping coolant (*been 3k miles now with no hint of burping...). The OEM cap appears to be sealing well enough on the TYC1918 at this point, so I'm driving on with this combo.

I may buy a Duralast cap to throw in the parts storage in back, just in case...
 
Joined
Dec 14, 2018
Messages
297
Location
Silverthorne, CO
Same issue with TYC1918 radiator cap neck and OEM Toyota radiator cap. I found that the cap doesn't seal nearly as well as on a Toyota Radiator, so was getting the shut-down boiling sounds from the radiator, with occasional burping of a cup or two of coolant out of the overflow bottle.

I traced this back to air bubbles in the system after a coolant fill from empty, and its since subsided from burping coolant (*been 3k miles now with no hint of burping...). The OEM cap appears to be sealing well enough on the TYC1918 at this point, so I'm driving on with this combo.

I may buy a Duralast cap to throw in the parts storage in back, just in case...
So the problem solved itself once the system was fully burped?

I know there are tons of threads regarding proper burping of the system, but I have found that a few drives with temperature cycles and the heater valve opened the system will purge itself no issue.

Have you also considered sanding down the cap neck?

@Rusty Marlin Sorry for hijacking your thread.... :flipoff2:
 

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