My '83 300D has a metal fan.

The '85 300TD (wagon) has a plastic one.

The plastic fan can turn even when the engine is off - turning it does not turn the engine.

Attempting to turn the metal fan on my '83 does not have the same effect - the engine attempts to turn too.

Is this normal?

Is there any advantage to either fan type?

__________________
JWJ
1983 MB 300D - > 430,000 miles - Deep Blue - Bilstein Comforts - 0-60 in 24 seconds - 27MPG
1985 MB 300TD (wagon) - > 275,000 miles - Manila Beige - Thule rack - 0-60 in 18 seconds - 22 - 25MPG
Biodiesel, Mobil Delvac 1, and Viton fuel lines!

Not normal, the clutch of the metal fan has failed. Replace it asap because the fan can fail (break apart) at high rpm with a frozen clutch!

The plastic fan is better. Its lighter, moves more air and is a more efficient design. Your 85 also has a smaller water pump pulley (0.9:1 instead of 1.09:1) which helps turn the fan and pump faster.

I would bet his '85 has the same pulley size as his '83. I found that the '84-'85 617.951s had the smaller pulley and the 617.952s of the same years didn't.

__________________
1983 123.133 California
- GreaseCar Veg System

Thanks!

Seems new fan clutches are not cheap... time for a trip to the yard.

Is this an easy DIY?

__________________
JWJ
1983 MB 300D - > 430,000 miles - Deep Blue - Bilstein Comforts - 0-60 in 24 seconds - 27MPG
1985 MB 300TD (wagon) - > 275,000 miles - Manila Beige - Thule rack - 0-60 in 18 seconds - 22 - 25MPG
Biodiesel, Mobil Delvac 1, and Viton fuel lines!

That may be the case. The fan and pulley I got were off an 84 300SD.

I don't have access to the TSB to check. Can somebody with AllData upload it?