OM603 fan clutch - PeachParts Mercedes-Benz Forum

inventor · #1 08-07-2011, 03:13 PM

Hi, I am kind a confused with all the reading about the fan clutch repair can some one summerize it please, like do i have to empty the reservoir first before adding silicon oil, what viscosity oil to use and what amount.

1994 S350 W140 /OM603
This is what I have so far.

15cc of 7000 cst silicone diff lock oil
Toyota Part # 08816-03001 is the 3000 cst oil
18ml of 10,000 cSt silicone oil

thanks..mike

sixto · #2 08-07-2011, 04:34 PM

You have a choice of silicone oil. Toyota sells the three viscosities you listed with corresponding part numbers; -03001 for 3000 cst, -07001 for 7000 cst and and -10001 for 10,000 cst. Expect to pay $12-15 for a bottle and you'll probably need more than one. Much cheaper to get silicone oil from a hobby shop but I don't know if you have as much selection. I've never seen an OE centistoke spec.

I don't know how you can empty the reservoir so just fill it. I haven't seen guidance on how much to fill it. It's trial and error as tedious as that sounds. You want the fan to come on full tilt for, I don't know, 15 seconds or so when the engine is started cold. Then it should disengage and come on when the air between the radiator and clutch is at about 100*C. This doesn't necessarily correspond to coolant temperature registering 100*C on the gauge. To me, getting the fan to engage on a cold start for a few seconds determines success. If it stays engages, there's too much oil.

To fill, remove the thermostatic strip and the plunger pin. Set a heat gun on the clutch as you rotate it. Use a syringe to force oil into the clutch. When it overflows, set the heat gun on the clutch as you rotate it. Lather, rinse, repeat.

I hope someone can offer shortcuts and more scientific methods of determining how much oil to add.

Sixto
87 300D

86-300sdl · #3 08-07-2011, 05:46 PM

I'd like to do mine today as well.

When filling should the unit be held vertically as when mounted or layed flat.

Is the heat gun used to expand the unit internals to draw or allow more fluid? Will a hair dryer suffice?

Thanks!

inventor · #4 08-07-2011, 09:53 PM

Quote:

Originally Posted by sixto

You have a choice of silicone oil. Toyota sells the three viscosities you listed with corresponding part numbers; -03001 for 3000 cst, -07001 for 7000 cst and and -10001 for 10,000 cst. Expect to pay $12-15 for a bottle and you'll probably need more than one. Much cheaper to get silicone oil from a hobby shop but I don't know if you have as much selection. I've never seen an OE centistoke spec.

I don't know how you can empty the reservoir so just fill it. I haven't seen guidance on how much to fill it. It's trial and error as tedious as that sounds. You want the fan to come on full tilt for, I don't know, 15 seconds or so when the engine is started cold. Then it should disengage and come on when the air between the radiator and clutch is at about 100*C. This doesn't necessarily correspond to coolant temperature registering 100*C on the gauge. To me, getting the fan to engage on a cold start for a few seconds determines success. If it stays engages, there's too much oil.

To fill, remove the thermostatic strip and the plunger pin. Set a heat gun on the clutch as you rotate it. Use a syringe to force oil into the clutch. When it overflows, set the heat gun on the clutch as you rotate it. Lather, rinse, repeat.

I hope someone can offer shortcuts and more scientific methods of determining how much oil to add.

Sixto
87 300D

Thank You very much this is very helpful. the amount is on this thread. now I have info so I can be brave..............

http://www.peachparts.com/shopforum/showthread.php?t=299746&highlight=fan+clutch

sixto · #5 08-07-2011, 10:23 PM

The clutch should be stored vertically but I filled mine horizontally. I think you have to so fluid distributes evenly.

I suppose you can use a hair dryer but it might take a while to get the interior of the clutch hot enough for silicone oil to flow.

Sixto
87 300D

86-300sdl · #6 08-08-2011, 07:59 PM

I just picked up a heat gun. Safer than trying to sneak the hair dryer into the garage...lol

winmutt · #7 08-09-2011, 08:51 AM

Personally I would just recommend a new plastic fan and clutch...