Gen 4 Viscous Fan

Greg_SA · Wed Nov 28, 2012 10:09 am

Hi,

I upgraded from a Gen 3 to a Gen 4 recently, and I seem to notice the viscous fan on the Gen 4 engaging quite often... is this normal?

On my Gen 3, it almost never engaged... only every now and then, when it was extremely hot, and I was standing still in traffic for a long time.

On my Gen 4, it was only 28 degrees outside, and while driving through town, a bit of stop go traffic, but not standing totally still for very long, I notice it engages.

Any opinions?

Thanks,
Greg

CATS · Thu Nov 29, 2012 8:21 pm

You sure it wasn't the aircon kicking in the fan?

CATS

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Greg_SA · Thu Nov 29, 2012 8:31 pm

If the fan was electrical, then I'd say it is possible.

But as far as I understand, on the Pajero there is a bi-metal strip that activates the viscous fan based on overall engine bay temperature (near the radiator).

outbackjack · Fri Nov 30, 2012 1:13 pm

I agree check the bi-metal strip, and when the car is switched off it should have some resistance to the fan when wanting to turn it by hand other than that there is no other checks according to the gen 4 service specifications other than checking for leaks of fluid from the viscous fan

Greg_SA · Fri Nov 30, 2012 9:27 pm

outbackjack wrote:I agree check the bi-metal strip, and when the car is switched off it should have some resistance to the fan when wanting to turn it by hand other than that there is no other checks according to the gen 4 service specifications other than checking for leaks of fluid from the viscous fan

I'll check it out, but it definitely is working. Even once at operating temperature, if I just let the car idle, eventually the fan will engage for while the disengage - so it does cycle, which is correct. The temp on the gauge is also fine.

I just almost never noticed the fan on my Gen 3... and on my Gen 4 is comes on at some point every day on my trip to work. I only notice it when I rev the car a bit after idling for a while - you can hear the roar of the fan. Then a short while later it is disabled again.

How often do you notice the viscous fan engaging on our Gen 4? Regularly or almost never?

Greg_SA · Mon Dec 03, 2012 12:08 pm

I noticed that on my Gen 4,the expansion tank doesn't have a black rubber seal (o-ring) in the cap - is this critical?

My Gen 3 has got a seal.

My understanding is that the expansion tank is at low pressure, so it should not matter

Greg_SA · Thu Dec 13, 2012 3:48 pm

Well, I had the Pajero at Mitsubishi Paarden Island, and they tested tge cooling system and viscous fan, and said everything is 100%.

I wasn't convinced. Too the car to Silverton Radiators, and they diagnosed a faulty viscous fan - engaging at just 40-degrees! Meant to be closer to 80-degrees!

So now I have to convince Mitsubishi to order the new viscous fan clutch ASAP hopefully without having to book the vehicle in again, so that it arrives before I leave for Kgalagadi next week Thursday! Car is still under warranty...