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.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

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.

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

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.

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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great info ya'll. just to clarify, on my 83 SD i can just replace the original metal fan/clutch with the updated plastic fan/clutch since it has that spacer for the water pump, correct? but i should also use the later version WP pulley to increase efficiency. the way i understand it is that the pre '81 617's are in need of the later model WP pump to engine housing?

your 83 SD should have a plastic fan already, and it should have the small pulley as well.
if it does not, it's either an EARLY 83 or the engine/fan assembly has been changed for an older one...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

bump, just want to make sure i got the info right

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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Attached Thumbnails

 

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!

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!