Overheating help and fan clutch advice

[hammerheadfistpunch]

Fan only really needed under about 25 - 30 MPH, and then normal airflow should keep temps down however, once you reach around 75 - 80 MPH the fan re-engages.

Regards

Dave

This is exactly why im hesitant to do the clutch mod. Its not acting like a fan issue.

Here is a graph of my drive home yesterday.

 

[Tools R Us]

This is exactly why im hesitant to do the clutch mod. Its not acting like a fan issue.

Here is a graph of my drive home yesterday.

That is higher than I would like. The FZJ80 is fan dependent, potentially at any speed, especially with a more restrictive brass radiator, they need more fan. Out of the box the blue hub a pretty wimpy, drain and fill with 30k will wake it up.

What clutch did you take out? Maybe tune that and stick it in to see how it works?

 

[Lopott]

what about using the land cruiser products 100 series fan and the scan gauge, just flip the switch when it runs high.

 

[hammerheadfistpunch]

what about using the land cruiser products 100 series fan and the scan gauge, just flip the switch when it runs high.

I looked into it, but something tells me it wouldn't have the desired effect.

Land Cruiser Products - LCP
"If your Land Cruiser is overheating, THIS FAN WILL NOT HELP."

 

[danthman114]

I looked into it, but something tells me it wouldn't have the desired effect.

Land Cruiser Products - LCP
"If your Land Cruiser is overheating, THIS FAN WILL NOT HELP."

I just installed that fan on Friday and took it out in the sand on Saturday with temps at 110 outside. it kept it below 200 where the same road the weekend prior it got just over 200. it stayed right at 198. I had 35 psi in the 33s and my 80 weighs over 6k. it worked but it wont keep it from overheating. its just a supplement to the stock fan. btw, my entire cooling system is only a couple years old. I put 20k in a new blue hub without the mod. I'm going to open it and try 30k and maybe a mod. mr tools, I might pm you to pick your brain since you live in practically the same weather as I do...

 

[auttiman]

So I'm overheating (shocked face!) and I need to know where to look next. I replaced a factory rad with the CSF when the factory one started leaking. Coolant is flushed with 50/50 Toyota red and doesn't appear to be leaking anywhere. New foam around the entire rad, shroud and fan in great shape.

symptoms

• heats normally and runs 187 for the first dozen miles regardless of temps, if its even slightly warm (70's) out then it sits around 190 with no load, go up a hill and it gets to 196. I can bring down the temps to 186 if I high idle. If its hot this takes a long time. If Im on the freeway and its spring weather aim doing 198 or higher. If im towing a trailer in these temps I will easily get into the 220-230 range where Im windows down heat on.
• The new in box blue hub fan clutch I bought seems to kick on normally
• It seems to only happen once the truck has been up to temp for a while, i.e. I can run it hard for 10-15 minutes with no change but once its started heating up it wont easily cool or stay cool.
• the heat coming off the trans cooler seems REALLY hot. I used my IR therm and got well above 230 on the exchanger at operating temp
• Revs only matter a little to cooling, it seems to cool better with LOWER revs than higher. i.e. if I can get out of 3rd and into OD towing on the flats it cools way faster than leaving it in 3rd with higher revs but low loads.

It sounds to me like either an air bubble (happens at speed, doesn't cool easily, temps raise quickly, etc) a clogged radiator or some other clog. I've burped it several times and it was just flushed and refilled.

the transmission has felt a little softer and I found out recently its been overfilled for a while. I took nearly a quart out to get it to the proper fill lines (it was at the hot line when cool) but the fluid is pink and doesn't smell burnt. Is there a possibility that the in/out lines on the trans cooler on the CSF are backwards? would that matter?

whats the best way to backflush a stopped coolant passage?

Faulty T-stat?

Tell me about the blue clutch mod. Does it REALLY work that well? Also, whats the final word on fluid weight and where to get it?

Thanks, this is only going to get worse as it gets warmer and I would love to solve this now.

196 is okay

 

[hammerheadfistpunch]

196 is okay

221 isn't

 

[-Spike-]

I just installed that fan on Friday and took it out in the sand on Saturday with temps at 110 outside. it kept it below 200 where the same road the weekend prior it got just over 200. it stayed right at 198. I had 35 psi in the 33s and my 80 weighs over 6k. it worked but it wont keep it from overheating. its just a supplement to the stock fan. btw, my entire cooling system is only a couple years old. I put 20k in a new blue hub without the mod. I'm going to open it and try 30k and maybe a mod. mr tools, I might pm you to pick your brain since you live in practically the same weather as I do...

I had cooling issues within a few years of an overhaul, found out that some of the tubes in the new radiator were clogged by small rubber bits. I assume it was from hoses that didn't get changed, i.e; rear heater, bypass, etc.

 

[hammerheadfistpunch]

new plot from going up the canyon this afternoon

I had cooling issues within a few years of an overhaul, found out that some of the tubes in the new radiator were clogged by small rubber bits. I assume it was from hoses that didn't get changed, i.e; rear heater, bypass, etc.

I really don't want to have to drain and pull the radiator, but it may be my next step to get in there and flush it upside down.

 

[ariff]

This is about what my 80 runs as well.. Sounds a lot like my operating temps.. I have not been all that concerned since the normal operating temp for the FZJ80 is 180-210 degrees.. I have only ever gotten up close to 210 when sitting in traffic. Once I start moving it drops down to around 198-200 ish.. I have a new 2 core rad, all new hoses, new 50/50 green coolant, redline water wetter, and 10k oil in my black fan clutch.. My temp prob is in the top water pipe..

 

[Kaninja]

I am often curious if these engines are highly susceptible to running very lean air/fuel mixtures and hence the excess heat that comes with that. Just a thought.

 

[baldilocks]

Who determines exactly what “excessive temp is”? Has it been proven that running at 200-205-210-215 all day long is detrimental? Or are we simply fixated on numbers and anecdotal rambling of fellow cruiser owners?

 

[OGBeno]

Nice. Spoken like a true contrarian.

 

[hammerheadfistpunch]

Who determines exactly what “excessive temp is”? Has it been proven that running at 200-205-210-215 all day long is detrimental? Or are we simply fixated on numbers and anecdotal rambling of fellow cruiser owners?

These are the numbers I've heard
183-186 T-stat opens (82c)
217 AC comes back (103c)
221 gauge moves off middle and jumps right on up to warm (105c)
226 AC kicks off (108c)

What I've come to believe here and elsewhere is that these systems don't like excessive heat. My gx runs fine at 217, no probablo, but 217 in an 80 is pretty hot and borderline danger zone. If mine was getting up to 215-217 and staying put or rapidly cooling when the load was off I'd be happy enough, problem is that it doesn't. It just keeps climbing until I intervene. I got up to 221 today on a 20 minute drive up the canyon with nothing in the truck but me and only moderate temps. if it was hot or I was pulling a trailer or if the grade kept going I would have had to pulled off and cooled down.

 

[hammerheadfistpunch]

I am often curious if these engines are highly susceptible to running very lean air/fuel mixtures and hence the excess heat that comes with that. Just a thought.

My Long term trim does favor command lean, but not a huge number, like a -3 to -5. om going to check for exhaust leaks before the first sensor tonight.

 

[Jason hansen]

I played around with different weights of silicon rc diff fluid. After installing my 8274 winch that blocks my entire radiator I used 2 ounces of Lucas 60k fluid in my stock Eaton fan clutch. Before I was having over heating issues, even without the aftermarket bumper and big winch. Now I have no issues with overheating. The stock fan clutch hooks up real good with heavy fluid in it. I don't know if this is the right way to set up a fan clutch but it works for me. I dare say my land cruiser fan could suck start a 747.☺

 

[baldilocks]

I played around with different weights of silicon rc diff fluid. After installing my 8274 winch that blocks my entire radiator I used 2 ounces of Lucas 60k fluid in my stock Eaton fan clutch. Before I was having over heating issues, even without the aftermarket bumper and big winch. Now I have no issues with overheating. The stock fan clutch hooks up real good with heavy fluid in it. I don't know if this is the right way to set up a fan clutch but it works for me. I dare say my land cruiser fan could suck start a 747.☺

What year is your 80? Eaton is the clutch often referred to as the black hub clutch?

 

[-Spike-]

new plot from going up the canyon this afternoon


I really don't want to have to drain and pull the radiator, but it may be my next step to get in there and flush it upside down.

I was able to see a few rubber bits in the few tubes visible through the filler neck. I took that rad apart and found that a few at the filler meant a lot more towards the driver's end. For $130 I felt better with a new rad, bonus that the brand I got has proven to cool better than any other in several trucks around here, bad reviews be damned.

 

[Jason hansen]

Stock oem fan clutch for a 96 fzj80. I know people say that at freeway speeds the fan clutch does nothing. From my experience having a fan clutch that hooks up makes a huge difference at freeway speeds.

 

[Desert Dino]

new CSF rad all new system including new oil cooler Tstat pump. and all the rubber. installed another spal electrical fan on top of the OEM manual operation
Blue FC mod 50 ml 30K oil 95F mod
toyota red
heavy Rig 6k Lb
external conditions 99F in the shade 170F metal in the sun
Measuring coolant temp by OBD1 scanner

tomorrow last trip to the desert 2 dayes and nights

i had a problem of overheating in the past going over 60miles on highway 70-80 it got hot 210F and once in extream hot day on trail it cut the AC so i opened windows and stooped AC and put heating on full it was 225F

i will see this trip if the 30K FC mode and the extra e fan will help

I have big hood openings to resale the heat from engine