Anyone have/know where to find an '81 - '85 fan and fan clutch?
 

Couple of days back, I noticed a clattering sound from under the hood of my 1975 300D - 115.114 Chassis, 617.910 Engine. I quickly noticed that the cooling fan was a bit loose. As I tightened down the bolts, I noticed that there were only three - not four.

Huh...so I wind up talking with Roy at PeachParts - great guy, btw - who suggested that I might want to replace the aluminum fan clutch and fan blade with the later model plastic versions. The reasoning being that this will improve mileage and cooling ability.

I'm in East Texas, near Nacogdoches - anyone know of a junkyard from which I might get these parts, or have these parts and are willing to sell them?

Thanks!

Be careful. The 75 617 has a different water pump that later models. Longer I think, although maybe shorter so be sure there's enough space for a later clutch and fan.

Yikes - thanks for the heads-up!

The plastic fans do not correlate with the year models that you listed. I am fairly certain that the metal fan was used until sometime '83 at the earliest.

Yes, this would not be an original part replacement - it was suggested as a recommended upgrade.

so the '84 and '85 OM 617's have the clutch plastic fan blades? is it just plug and play? (like use the entire clutch/plastic fan combo or can you remove the plastic fan and use it on the existing clutch?)

I am not at all sure and am going to ask my source of info for more details before I do anything...

The metal and plastic fans do not use the same clutch.

Understood. But the probablilty of finding a plastic fan at the junk yard on an '81-'83 model isn't very good.

Answer
 

The earlier water pump is shorter.
If you need to shift the clutch/fan assembly forward:
There is a spacer on the 1981 and later water pump "attached picture".

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so, in addition to the fan/clutch, they would need the bolts from the plastic fan? or are the thicknesses the same on both types of fans?

also note, that the plastic fans came standard on all 83 and newer 617's, and if you can find an SD, get the fan, clutch, and water pump and crank pulleys as well, and new 935/1000mm alt belts. you will gain, not only a more durable fan that cools better, but you will gain a higher RPM water pump as well!

Answer
 

The clutch to water pump bolt pattern matches, and they are an alternative - upgrade.

The plastic blade has better airflow and is lighter.

The aluminum blade will not function correctly on the later upgraded clutch, even if you can mount it, the air flow - mass - thrust - torque load is wrong for the design.


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FYI
 

If my memory has not failed, the pumps are not compatible.

Should you desire to upgrade, the pump to block housing must be replaced with the newer unit.

The old style water pump
MB# 6172000620
$350.00

The new style water pump
MB# 110 200 17 20
$50.00 - $70.00

Changing the water pump to a newer version, I strongly suggest you replace the pump housing to block gasket.

An easy diy that is worth the extra effort.


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IMO
 

At this moment, just change the fan/clutch assembly.

You can collect additional parts at leisure.

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I did not mean the water pump... I meant to convey that the PULLEY on the water pump, along with the crank pulley for dual belts would be an upgrade over stock...