560SEL fan & fan clutch install on 617
 

I read a brief mention that a 9 blade fan and viscous clutch from a W126 560SEL (and other such models) is a direct bolt on/fit to the OM617, even fits the shroud without modification.

Has anyone done this or have experience?

It's a big gnarly fan that will move a lot more air than my stock 1983 300CD 6 blade fan. I'm looking for better heavy traffic bumper to bumper cooling and AC performance. Car suddenly ran hotter at extended idle, thought it was the visco fan but new thermostat cured it.
I want to install this wicked V8 setup but would like to hear from people who've done it.

If it fits I cannot see any problem in it. It might cause more load on the water pump bearings though....just a wild guess as this subject has not come up here before I don't think.

Yes, it fits. I run a m117 fan, 450sel centrifugal clutch, and 85 OM617 (smaller) pulley. you will need shorter belts... I cold not get a the clutch for the 560 fan to stay engaged at idle to help with a/c even after trying a few and tweaking the bimetal strip so i used an older centrifugal non thermal clutch. Not as efficient as it is pretty much completely coupled until high rpm cut out but living in Texas i just want to keep my a/c and engine happy. The fan blade itself will sit closer to the top of the shroud but it all fits with a little adjustment. Fan clutch bolts are also easier to get a wrench on!

Thanks for the info. I am waiting on a delivery from the auction site of a 560 fan & clutch.

If the fan clutch is weak or bad. RockA*** has US Motors fan clutches at a good price and I read here they are good. They have the coiled bi-mettalic spring instead of the flat one. Coiled springs are easy to modify so the fan locks up at an earlier temperature.

One end of the spring ends in a tang that's buried in silicone to hold it in place. Dig it out and re-bend the tang so it's 1/8 inch shorter.
I did that to my GM 6.5 diesel van and it kicks in just under 200°. If the 6.5 goes over 210° for any length of time... Kiss it goodbye.

I hear you can remove the flat bi-mettalic spring and grind the pin beneath it 1/16 shorter to have the clutch engage earlier but I have never done that.

I believe the fan clutch mod is a good thing to do, when it's hot out and the motor is running hotter than normal fan clutch will lock in much earlier than stock. When temps are normal it will freewheel helping power and economy- but not the AC.