Auxillary Fan Operation

[shane@mbtech]

No electric fan. Viscous only Alex.

Originally Posted by alexk

shimmy, I could be wrong but I think the electric fan is also installed on the non-AC cars.

The fan is used to provide additional cooling to the engine. It's not used just for the AC.

Here are the maps that show how the fan is operated.

Temperature (°C)|Operation/speed (%)
|49°C|0%
|50°C|30%
|70°C|40%
|80°C|65%
|85°C|83%
|90°C|100%

The second map, that changes the voltage supply depending on the speed.
Above 140km/h it's deactivated.

speed (km/h)|Voltage (index)
|0 km/h|1
|50 km/h|1
|100 km/h|1
|120 km/h|0.5
|140 km/h|0
|200 km/h|0

[shimmy]

Originally Posted by lawsy

No electric fan. Viscous only Alex.

I find that strange Lawsy as surely when the cr stops and the fan is running, non a/c cars must have the same cooling (it's not a/c that's running

[shane@mbtech]

Viscous fan is temp controlled. The viscous coupling has in laymans terms a fluid that when hot causes the 2 sides of the coupling to turn together.

Imagine the coupling spinning with engine speed as it's attached the pulley. When cold no drive is transmitted through to the fan side of the coupling. When hot the fluid changes and locks the fan.

Approx 30mph then the opposing air does more than the fan could pull through.

[shane@mbtech]

Originally Posted by shimmy

I find that strange Lawsy as surely when the cr stops and the fan is running, non a/c cars must have the same cooling (it's not a/c that's running

The non AC cars have the viscous fan to cool them.

[shimmy]

Originally Posted by lawsy

The non AC cars have the viscous fan to cool them.

Just engine driven?

Not electric?

[shane@mbtech]

Originally Posted by shimmy

Just engine driven?

Not electric?

Yes shim, just engine driven on m3.

Have a little read http://en.m.wikipedia.org/wiki/Fan_clutch. It gives you the basics.

My viscous fan was new on my Csl as it started overheating one day whilst queuing in a petrol station.

[Mike R]

Originally Posted by lawsy

Yes shim, just engine driven on m3.

Have a little read http://en.m.wikipedia.org/wiki/Fan_clutch. It gives you the basics.

My viscous fan was new on my Csl as it started overheating one day whilst queuing in a petrol station.

Is the CSL viscous fan ECU controlled or bi-metallic metal strip?

[CraigMillwardCroft]

Now I am getting confused mine has two fans, one viscous back of rad on engine and one in front of the rad electric which is standard, came on today while car was standing with engine running for long time.

[Mike R]

Originally Posted by CraigMillwardCroft

Now I am getting confused mine has two fans, one viscous back of rad on engine and one in front of the rad electric which is standard, came on today while car was standing with engine running for long time.

I suspect that the electric fan is to provide the low speed / traffic cooling that the viscous one cannot meet the demands for, so perhaps there is a cross-over point where the two are not operating as efficiently as the cooling demands?

[shimmy]

Originally Posted by CraigMillwardCroft

Now I am getting confused mine has two fans, one viscous back of rad on engine and one in front of the rad electric which is standard, came on today while car was standing with engine running for long time.

I presume you have a/c.