customknight said:

The aircon has never worked and the pressure is at 0 so it's definitely gonna be knackered and I really cannot be bothered to spend ages getting air con to work for the three days we'll need it!!!
So I've never seen the fans work, but I used your advice in a bother post about earthing the blue black lead to ground. Relays clicked but only the left fan came to life. Tested power supply to the other fan and 12v we're present but not working. It spins but catches when forced manually. It's just dead.
How do I run a definitive test of the viscous fan?

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kevwill said:

I've read that some peeps have stuck a rolled up newspaper in the fan when running, and if it stops the fan you need a new coupling. If it destroys the newspaper, rips your fingers off and breaks the blades off the fan, then the coupling is good.
Never really fancied this test so I replaced mine when I fitted a new water pump.
Check that it hasn't got 'Britpart' stamped on it. If it has, change it for a decent quality one.

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customknight said:

The aircon has never worked and the pressure is at 0 so it's definitely gonna be knackered and I really cannot be bothered to spend ages getting air con to work for the three days we'll need it!!!
So I've never seen the fans work, but I used your advice in a bother post about earthing the blue black lead to ground. Relays clicked but only the left fan came to life. Tested power supply to the other fan and 12v we're present but not working. It spins but catches when forced manually. It's just dead.
How do I run a definitive test of the viscous fan?

Click to expand...

kevwill said:

When you press the AIR CON OFF button (light on) the air con is off. Does exactly what it says on the tin.
So when the engine overheats, your not losing any coolant from the expansion tank overflow, and the system isn't overpressurising??

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stjohnsmythe said:

I think the P38 is the only car in the world that has a button that lights up when it's turned off and not on!

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customknight said:

Is there any way to test the thermostat. I mean other than the put in a pan test. It's obviously working in that regard as it's opening and all the pipes are getting hot.
With regard to the rad; new one or attempt to de scum the old one?

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wil2813 said:

I used to fire up the twin fans on my old p38 using a kenlowe fan controller about £40

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customknight said:

Is there any way to test the thermostat. I mean other than the put in a pan test. It's obviously working in that regard as it's opening and all the pipes are getting hot.
With regard to the rad; new one or attempt to de scum the old one?

Click to expand...