HDJ81 possible cooling issue

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M

Martin White

Joined
Mar 31, 2006
Threads
89
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1,102
Location
Abbotsford, B.C.
I'm not actually certain I actually have an issue, BUT...during a trip through the Coquihalla (for those of you who don't know this stretch of road in B.C., there are some sections which run close to 20 km of very steep hills, both up and down) I discovered that on 1 particularly long section going up, that my coolant temp rose to the bottom of the red zone, but no idiot lights went off. When I downshifted and ran at approx. 3000 RPM, the engine cooled off. Is this normal considering the heat (approx. 30 C) and that length of hill, or do I have an issue with the cooling system?
 
This hill seems to be notorious for overheating diesels.
You said you downshifted to 3000 rpm.
If you went from 5th to 4th you were probably overloading it.
If your coolant system is clean,leak free and holds good pressure then I would quote the manual "revise driving habits" ;)
 
My truck has never hit the red.
This includes when I towed a 3400lb trailer back from Seattle.
Got warm pulling up some hills, but I went easy on her.
Never went passed 2/3 when towing. As soon as it started to climb I let of the fuel and it cooled down right away.

Maybe chech your thermostat.
Do you have a pyro?
How hot was your exhaust?

Cheers,
Nick
 
Thanks Greg. I read the whole link, all 8 pages. It looks almost certain that the culprit here is the fan clutch. Do you know the part number for the HDJ81? Can we get the aftermarket units as in the US? Is there anything better than OEM or would you just recommend going OEM?
 
Up that hill last year with family, roof rack, dog and lugage. Never dropped out of overdrive until about one mile from the top.

I was very impressed and the needle did not budge.

My gas pot 1994 80 dropped two gears by the top and was reving to beat all.
 
Martin White said:
Thanks Greg. I read the whole link, all 8 pages. It looks almost certain that the culprit here is the fan clutch. Do you know the part number for the HDJ81? Can we get the aftermarket units as in the US? Is there anything better than OEM or would you just recommend going OEM?
Click to expand...

Hi Martin

I don't know enought about it to say, and do not know what will cross over from a North American application. Know anyone that has a spare FZJ80 fluid coupling they want to part with for a day so you can see if the bolt pattern is the same? Maybe Semlin has a spare he can loan for research purposes. Then we will know if the N/A aftermarkets ones will at least fit.

EPC is not much help. 16210-17040 shows as the correct JDM number. On the world discs EPC shows 17010 as the correct number. I would "think" the bolt pattern is the same, and the difference would be the weight oil used inside, but without having both in front and apart to compare who knows...

Ens Lexus Industrial Division in Saskatoon can get the HZ coupling new for you, which will fit on your truck. IIRC Sheldon ordered a new one from Ens, and it did very well on his recent trip to Cali, in the middle of the heat wave they had last month. You could simply order some of the heavier oil, and swap yours out as a test...following the instructions explained in that thread.

Also, has a valve set been done on your truck? Having the valves opening and closing in spec will help with heat evacuation. You need a SST to lower the collar to get to the shims. Ciaran has one.

A block and cooling system flush to ensure all is okay there might not be a bad idea either.

hth's

gb
 
i do have an extra you can try when i return from vacation next week. fzj80 fan seems to be the same fan as a bj74 if that helps but i can't speak for thr fan clutch itself because the bj74 i saw had a fixed fan. the real question will be what flavour of oil is inside an hdj81 fan clutch since we know the fzj80s are the same part number in oz and here but contain different oil thickness whihc affects when they activate. an option is to replace that oil from cruiserdan and maybe the o-ring if fatigued which you would need to source somewhere.
 
I'm not sure I'll be able to take advantage of your extremely generous offer because my workload is very very heavy over the next couple of weeks. I may end up taking the truck to Ciaran for some TLC and to look after several small issues that have developed.
 
Greg_B said:
Read this thread and maybe include a check/servicing of the clutch fan.

https://forum.ih8mud.com/showthread.php?t=98684
Click to expand...

For those with the 1HD-T; can you hear a difference when the fan clutch locks up? In my Trooper, I can easily hear it engage, but on my HDJ81 I've never heard it. I'm wondering of this contributed to my ATM overheating.

-Steve
 
wussyPup said:
For those with the 1HD-T; can you hear a difference when the fan clutch locks up? In my Trooper, I can easily hear it engage, but on my HDJ81 I've never heard it. I'm wondering of this contributed to my ATM overheating.

-Steve
Click to expand...

never know when it engage in my 80 or in my 60 series ..
 
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