Cooling fan clutch

[fuzzylogic]

Fan clutch is an easy diagnosis, if it stops when you turn off engine, it's ok, if it still spins after shutting engine off, it needs viscous oil top up...

 

[BarneyB]

Fan clutch is an easy diagnosis, if it stops when you turn off engine, it's ok, if it still spins after shutting engine off, it needs viscous oil top up...

Yeah that's what I thought too...because it makes sense.
And mine was/is spinning-on a bit at shut-down.
But if you do too much googling & foruming (like I have) you can find arguments for/against that test.
Some say they run-on after shut-down any time...?
Would anyone mind doing a shut-down test on their D40 by counting the seconds for me?
(preferably as close to full operating temp as possible)

I went for a long drive today and the issue is slightly better, but definitely not fixed. It still sits at 91 degrees at 90-100 km/h with bugger all pedal/load.
And as soon as you squeeze the pedal for any incline it jumps up immediately.

I've pretty much decided to do 2 things next:
1. More oil in the fan clutch
2. Temporarily remove the winch controller.

 

[paddyjacka]

Yeah that's what I thought too...because it makes sense.
And mine was/is spinning-on a bit at shut-down.
But if you do too much googling & foruming (like I have) you can find arguments for/against that test.
Some say they run-on after shut-down any time...?
Would anyone mind doing a shut-down test on their D40 by counting the seconds for me?
(preferably as close to full operating temp as possible)

I went for a long drive today and the issue is slightly better, but definitely not fixed. It still sits at 91 degrees at 90-100 km/h with bugger all pedal/load.
And as soon as you squeeze the pedal for any incline it jumps up immediately.

I've pretty much decided to do 2 things next:
1. More oil in the fan clutch
2. Temporarily remove the winch controller.

After engine is up to operating temp stick a rolled up newspaper on the fan when idling - if you can stop the fan then it is not working correctly

 

[paddyjacka]

After engine is up to operating temp stick a rolled up newspaper on the fan when idling - if you can stop the fan then it is not working correctly

I had an overheating problem years ago like this on a car - not a Nissan - the clutch fan was the type you cannot recharge but 4 strategically placed tech screws turned it into a fixed fan - never overheated again but did take a while to warm up lol

 

[BarneyB]

After engine is up to operating temp stick a rolled up newspaper on the fan when idling - if you can stop the fan then it is not working correctly

I tried that and I couldn't stop it turning.
But turn the engine off and it spins freely for quite a few seconds.
Conflicting results.
Go figure.

I put quite a bit more oil in the clutch today, but haven't road tested it yet...

 

[fuzzylogic]

When the fan is full of viscous oil, it stops abruptly with the motor stopping. No arguments, the oil is cheap, and it's a straight forward job. A top up of viscous oil, and the ute runs cooler, you'll notice how loud the fan appears to sound, as it's doing it's job properly. This isn't theory, it's real world observations from a D40. Also, observed the same results with my son's Vitara. It really makes a big difference.

 

[Jimjet61]

OK update...

This last week I took the radiator out of the Nav & had it flushed & tested with the local Rad specialist. It passed with flying colours. Full flow from every tube. So I cleaned the air side & put it back in the ute.
I replaced the thermostat with a new Tridon "high flow" unit.
I flushed the system with cooling system chem before disassembly.
I removed the thermo fan clutch & disassembled. Inside it looked great. Oil was clean & more importantly, present. I tested the bi-metal coil with a heat gun & it opened the internal valves no-worries. I added half a bottle of new oil (about 6-7ml) and boxed it back up.

I also fitted a Tillix boost control valve & needle spool valve and have just got back from a test drive & tweak. I figured the Tillix might help lower engine temp a little, via EGT's...on top of the other benefits it brings.

So...
It's too early to say the high coolant temp issue is fixed because I need to do some more highway miles....particularly uphill.
But tonight I did a short, flat, highway drive at 110km/h for about 5 minutes. The coolant temp rose briefly to 92 degrees and then stayed around 90-91 degrees. Ambient temp was around 12 degrees.
Driving around the subs from red light to red light it seems to run a little cooler....stays in the upper 80's.
It's always been highway driving at steady state throttle, uphill, that causes the spikes. Not stop-start around town.

Since the radiator was not the smoking gun I thought it was, I now have to find other things to eliminate...
So I'm leaving a question mark over the fan clutch. Not sure how to prove convincingly it's good....or buggered...?
And the winch controller might be the problem...but again, might not. It has an upward deflective angle to it that might be working like a mini-spoiler at high speed & pushing air up over the bonnet....right in the middle of the rad.
Local Rad guru reckons if the heater in the cabin is hot, then the water pump is OK. Cabin heater works like a furnace. No other evidence that the water pump is tired...

Barney, what vehicle have you got?

 

[johnl56]

He has a D40 by memory.

 

[BarneyB]

Barney, what vehicle have you got?



Yep '08 D40 STX d/c 4x4 VSK

Apologies for the late reply!

 

[BarneyB]

I'm due to follow-up this thread with more findings... but wanted to get more Summer kms travelled before making conclusions...

 

[Supermike]

I have the opposite problem, on the opposite side of the world. So it's winter here, -3 at the moment. What's nuts is, my fan stays on until the truck has warmed up, so 15-20 minutes of driving...

 

[Old.Tony]

I have the opposite problem, on the opposite side of the world. So it's winter here, -3 at the moment. What's nuts is, my fan stays on until the truck has warmed up, so 15-20 minutes of driving...

Your fan might be turning over with the motor but unless that clutch has engaged, it won't be turning over with any serious amount of force so it won't be pulling a lot of air. Do the engine-off test to find out: start the car, have a helper stand ready at the key, with the bonnet up watch the fan. When they turn it off, what YOU want to see (with a cold engine) is the fan running a few revolutions after the engine has stopped. If that's the case, there's nothing wrong with your fan clutch, but may be something wrong with the thermostat.

 

[Supermike]

Your fan might be turning over with the motor but unless that clutch has engaged, it won't be turning over with any serious amount of force so it won't be pulling a lot of air. Do the engine-off test to find out: start the car, have a helper stand ready at the key, with the bonnet up watch the fan. When they turn it off, what YOU want to see (with a cold engine) is the fan running a few revolutions after the engine has stopped. If that's the case, there's nothing wrong with your fan clutch, but may be something wrong with the thermostat.

Oh it's moving some amount of air! You want to hear the noise, it's like a 20 year old HGV! I think I know what is causing the issue, but not tried my fix yet.

 

[Old.Tony]

Oh it's moving some amount of air! You want to hear the noise, it's like a 20 year old HGV! I think I know what is causing the issue, but not tried my fix yet.

The centre shaft might have seized? That's unusual, but not impossible.

Good luck with your fix.

 

[Supermike]

The centre shaft might have seized? That's unusual, but not impossible.

Good luck with your fix.

I think it's a temp sensor issue... Likely in the EGR cooler, likely because I blanked the EGR pipe at the intake side and EGR valve is stuck wide open. That's my thoughts as this is when the problem started and the fan does go off once thermostat opens. If the ambient air temp stays above 10DegC (not often in Scotland) the fan doesn't have this issue at all. Apologies for hijacking the thread.