Viscous fan problem

Hi. When running I can stick my hand in the fan, stop it and set it spinning backwards, Yes I was born that way!! Anyway, is that normal? My temp gauge doesn't work, any ideas? New blue and brown sender units in the head. Just bought it and beginning to think its a lemon. It's a 98 2.5dse RR. Any help appreciated! Cheers

Procare said:

Hi. When running I can stick my hand in the fan, stop it and set it spinning backwards, Yes I was born that way!! Anyway, is that normal? My temp gauge doesn't work, any ideas? New blue and brown sender units in the head. Just bought it and beginning to think its a lemon. It's a 98 2.5dse RR. Any help appreciated! Cheers

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If the engine was hot when you stuck your hand in and you still have a hand then the viscous coupling is shot. If it has aircon I can give you a mod to use the aircon condensor fans for cooling.
All P38's are lemons, they are not cars, they are hobbies

Hi. Thanks for the quick reply, yes it has air con, any cheap fix would be fab. The engine was hot, it wasn't my hand, used the wife's!! I do miss my old 110csw, yes she was a V8 but what a machine!!

300tdi viscous couplings are the same as the one used in the diesel p38 so it dose fit and it is alot cheaper than the one for the p38 should be around £35 and i put a new thermostat and coolant temperature sender to get my temp gauge to work

Crikey that's not too expensive. One bit that was worrying me is that the nugget who owned the lemon before me has attacked the viscous fan nut with god knows what and mutilated it! I do not think that it will remove easily?? Any tips??

Thanks for the email datatek.

Procare said:

Hi. When running I can stick my hand in the fan, stop it and set it spinning backwards, Yes I was born that way!! Anyway, is that normal? My temp gauge doesn't work, any ideas? New blue and brown sender units in the head. Just bought it and beginning to think its a lemon. It's a 98 2.5dse RR. Any help appreciated! Cheers

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Hi I had the air con fans wired up, they work well, i'm now in the middle of changing the viscous fan. So i though while im there may as well flush out the rad and clean between the fins.

the viscous unit should not be that tight i used a good heavey duty screwdriver and jammed the pulley up by holding the srewdrive against two of the pulley bolts while i used a 32mm spanner to crack the viscous nut off ita about half hour job if you have the right tool at hand

Hi. Yep just done it, it was a breeze, thank you! Bad news - just fired her up and the system is pressurising, guess I've got a head gasket to play with next!!

Procare said:

Hi. Yep just done it, it was a breeze, thank you! Bad news - just fired her up and the system is pressurising, guess I've got a head gasket to play with next!!

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If it's overheating and pressurising, it's more likely to be a cracked head than a gasket I'm sorry to say.
There should be a fair bit of pressure in the system when the engine is hot.
Check that there is no air in the system.

How do I check for air in system? I filled it up via the top hose and the heater blows hot, as it was warming up the coolant rose from max mark to the top of the bottle, I splashed some out and put the cap back on and very soon the hoses were solid. Waited a bit and carefully took the cap off and she was a gushing!!

Procare said:

How do I check for air in system? I filled it up via the top hose and the heater blows hot, as it was warming up the coolant rose from max mark to the top of the bottle, I splashed some out and put the cap back on and very soon the hoses were solid. Waited a bit and carefully took the cap off and she was a gushing!!

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If you take the cap off when the engine is hot the water will gush out. Raising the pressure increases the boiling point of the water, remove the pressure and the water will immediately boil.
I think the pressure cap is 14psi so the hoses will feel pretty solid when hot.
Air in the system will cause the water level to rise in the reservoir as the air expands.
I get the air out by rapidly squeezing and releasing the hoses with the engine idling and the cap off the reservoir, topping up as required.

Will give it a go! Cheers

From work shop manual, coolant refill: (Was lucky, it worked for me, think slow fill did the trick)
Disconnect radiator bleed hose at the radiator.
13. Blow through hose to clear any residual coolant.
Reconnect hose.
CAUTION: If radiator bleed hose is not
cleared of coolant, air may become
trapped at top of radiator during refill,
leading to subsequent engine overheating.
14. Fill expansion tank until coolant is level with
base of neck.
15. Start engine, continue filling at expansion tank
until coolant level stabilises at the ’COLD
LEVEL’ marking.
16. Run the engine until the thermostat opens (top
hose becomes warm).
17. Stop engine, allow to cool.
18. Check coolant level, top-up as necessary.
19. Refit expansion tank filler cap.

Cheers thanks. I've read about the water pump issues elsewhere on the forum so popped mine out this morning, the plastic blades were in two pieces and the back bit had fallen off! I've got a replacement one with the metal blades, only £40, will fit it tomorrow and refil as per the above guidelines and see where we go from here! Ps the coolant was around 99% radweld! Lots of the copper looking stuff everywhere, it also has a new rad, obviously the previous owner had probs!