cooling fans: do I need both?

[penderb]

Hello

1986 W124 300 Auto diesel with aircon(not working, doesn't bother me)
Problem: cooling fan in behind main radiator has become worn & very loose, and thus is very noisy on tickover & when I turn off engine. But there's a second big fan on the outside of the rad. Can I just dump the noisy inner fan & rely on outer one or not? Why both fans?? what's the relationship between both, if any.

Billy

 

[kid-jensen]

Cooling Fans Do I need both?

Billy,

On my old car, I ran without the viscous fan, just relying on the electric for 4 years without problems.
You need to check that the electric one comes on though, they sit there for months doing nothing, then suddenly they are asked to do some work. They may have other ideas.
If the viscous fan is noisy, it may have lost it's fluid and won't be working anyway, check it with the famous "carrot test". If it fails, it's just dead-weight, so throw it away.....

The first time you get stuck in traffic with only the electric fan for company, keep an eye on the temperature gauge, if it gets much above 100C it's probably wise to put the heater on (at full boost) before things turn nasty. The electric fan should certainly be on at that temperature, and it should be gradually reducing it. If not, and the temperature continues to rise, the heater is your last hope.

I hope I haven't put you off, as stated I got away with it for 4 years, and it makes getting to the front of the engine so much easier.....

 

[penderb]

Hi Paul

No, you certainly haven't put me off. Been tinkering long enough to try things & keep the old eye on changes I make, once I get the good tips on how to proceed with a fix, I'm more than happy to try your advice.
Is viscous fan easy to remove???

Billy

 

[kid-jensen]

Billy,

Happy to hear you consider yourself competant!

The viscous fan is held on with some allen or torx headed screws, an allen key fit's both but it's tight and may need cutting down to get it in there.

Alternatively, use a 1/4inch torx bit from one of those screwdriver sets and a 1/4inch ring spanner.

If you're leaving the fan off, may as well take all the ducting and plastic radiator covers off too, should be good for at least 1/2 second of your 0-60!

If the viscous unit still works, be sure to store it upright (the way it's mounted in the car) so that the fluid is less likely to run out. They're not cheap, so well worth preserving if you find you need them in the future...

 

[penderb]

Cheers Paul

Will give it a go.

Billy