Fan Clutch

[Kristopher]

So I replaced my fan clutch last year in hopes to solve a cooling problem. I have replaced every concievable piece of the cooling system since and I am still getting a low speed/high load over heating problem.

Can I get some insight as to the proper operation of the fan clutch? Mine just seems to spin willy-nilly with no particular lock up. It does seem to catch on initial morning start ups but after that, nothing.

Please help!

-Kris

'95 Classic SWB 3.9

[Landy-Andy]

Hi Kris,
The fan is a tricky item to confirm, the only way I know is to;

-Try turning the fan blades by hand when engine is cold, & then again try turning it after a run when the engine is hot.(obviously turn the engine off when doing this! ) When the engine is hot the fan blades should be much harder to turn (greater resistance) & when cold the fan blades should be easier to turn by hand.(less resistance). If this proves to be correct on yours then you fan is probaly OK.

You mentioned you have changed most cooling system items, maybe you could list them so we can see what else it could still be?

good luck,
Andy

[Kristopher]

Thermostat
Upper and lower hoses
Radiator has been "rodded out"
Fan clutch
Pressure cap
resovoir tank

I can turn the fan by hand hot or cold with the same resistance it seems. I also tested it when running by stopping the spinning fan whth a wooden handle to see if the clutch would provide any resistance. I ran it in my garage for 20-30 minutes and no resistance was felt. It was hot because I could hear the coolant bubbling in the upper hose when I shut it off.. I wonder if I have a bubble in the system... hmm

-Kris

[Landy-Andy]

This posting from the Disco forum sounds very similar to your problems....take a read,

http://landroversonly.com/forums/sho...ghlight=heater

They were thinking air pocket?

Andy

[nairbo]

If you replaced the clutch fan with a new one it should be ok
you cant just spin it by hand to check it , as it has a series of valves with a viscous fluid flowing around inside as the "clutch slips ", with some sort of heat sensitive plates that when they heat up and flex to close the valves and prevents the viscous fluid from flowing thru the valves .
Spinning wont work
When engine is HOT open bonnet and give engine a good rev you should get a very big blast of hot air out of fan
If not sure find one that works on another RR and compare

The other thing to do is check youre temp gauge is reading correctly,
I borrowed a hand held temp gauge and found when my dash temp was near in red the engine was only at 76 degC , so I just replaced my temp sender and all is ok ......for now
Brian

[Kristopher]

I may have a go at bleeding the system again. This is really frustrating because the high load/ low speed stuff is where it counts for off roading. I do not have any issues at all on the freeway or in town. Odd indeed.

-Kris

[Landy-Andy]

Hi Again,
How about the water pump?

First, Check your fan belt is not loose & slipping.

I wonder if when at speed the movement of air is doing all the cooling, but at low speeds & idle the lack of "through air" is showing up a weak or inefficient water pump causing overheating?

Are you retaining all your coolant, or does it need topping up from time to time?

Also, when cool, bleed off the water system (get all the air out) using the highest point which is the the little stand pipe just before the heater hose connections.

Andy

[Kristopher]

I guess I forgot to mention that I did replace the water pump too. The '95's have the serpentine belt. I replaced it and the tensioner a year ago. I do not think it is slipping. I am retaining coolant. Although it did bubble through the pressure cap the other day when I was testing the fan clutch. The stand pipe... Thanks, Andy.

-Kris