viscous fan - update

[andycook]

After servicing the viscous fan a few weeks ago, and putting too much silicone fluid in - mean fan on constantly from cold engine, i looked at it again.
Poured some fluid out of the fan clutch.
Now, fan is off and easy to spin from cold until engine temp needle hit normal running temp (i.e. about 3 miles driving), and the fan clutch stiffens up (not solid) just a fair bit of resistance i.e. only spins about 1/4 turn when flicking it, and you can hear it roar when accelerating in low gears.
its a 3.0 TD engine and I seem to be getting about 23 mpg, Then best i have had is 25mpg before servicing the fan, on a long motorway cruise 65-75mph.
I have noticed a slight loss of power, nothing drastic.

my only concern is that i should only hear the fan 'roar' when the engine temp is getting too high. I doubt taking any more silicone fluid out of clutch will help this, any ideas?

andrew

[Vagrant No2]

After servicing the viscous fan a few weeks ago, and putting too much silicone fluid in - mean fan on constantly from cold engine, i looked at it again.
Poured some fluid out of the fan clutch.
Now, fan is off and easy to spin from cold until engine temp needle hit normal running temp (i.e. about 3 miles driving), and the fan clutch stiffens up (not solid) just a fair bit of resistance i.e. only spins about 1/4 turn when flicking it, and you can hear it roar when accelerating in low gears.
its a 3.0 TD engine and I seem to be getting about 23 mpg, Then best i have had is 25mpg before servicing the fan, on a long motorway cruise 65-75mph.
I have noticed a slight loss of power, nothing drastic.

my only concern is that i should only hear the fan 'roar' when the engine temp is getting too high. I doubt taking any more silicone fluid out of clutch will help this, any ideas?

andrew

Andy
The fan should never lock completly . It should roar as described when at the correct temp to start to drag at temp . It should quieten down as engine speed settles and cruise speed is reached .
I think Andy (Polegate) says the bi mettalic strip is adjustable to help vary the temp that final bit .

[andycook]

It never locks completely
but if I have been cruiseing on dual carriageway, then come to a roundabout for example, and pull away from that, the fan roars in the low gears, and you can hear it when cruiseing, but its quieter then as revs are lower.
maybe the metal strip needs adjusting

[Tallyman]

Since I did mine in the summer I've not had any overheating but also don't hear the fan roaring. Mind you I can't hear the turbo cutting in either but I know it does from the acceleration.

As to mpg, went up to London over the weekend and deliberately kept the max speed down to 60 mph. Bl..dy boring on the M-way but mpg up to 29. That's the best I've had from it. Usually 23-24 when using the heavy right foot but it's more fun at 80+.