Does anyone know if I need a special tool to change the fuel filter or what size wrenches? Also, how long should a filter last? I have 165,000 miles but am unsure of the last change or if there was one.

Secondly, I have fan problems that seem common. My first fan stopped working so I replaced it with another used one I bought on E-Bay..I know I know...but it was only 20 dollars so I thought it might be worth a shot. It worked for two days and stopped. It just free spins and doesnt lock up when it is supposed to.
Also, niether of the auxilarary fans come on when they should. I replaced the sensor (new from Mercedes) and inspected all the wires and resistor.
The fans do engage when the AC is used, so I know the fans themselves work. Im lost on this one.

Please help! Im at wits end with the fan issue. Its around 100 degrees lately and the only way for it to stay moderately cool is to be in motion.

Thanks guys!

EDIT: Upon further thought (see lower posts)






DON'T DO WHAT IT SAYS BELOW






(I've just left it there for posterity)



I think your fan clutch needs replacing. Try this - when the car is running, try to stop the fan with your hand - BE VERY CAREFUL. Basically, if you are able to stop the fan with your hand, the clutch isn't doing its job. The way my mechanic put it was "I shouldn't be able to do this, the fan should take my hand off". Obviously the car should be nice and hot - 100 C or so for this test to be valid. Again, be careful and do this at your own risk.

The fans come on low speed when the AC is at operating pressure, it takes mine about a minute for mine. They come on high speed when the engine gets over 106 deg C, that is controlled by a variable resistance sensor located about a third of the way from the back of the engine on the top of the cylinder head tucked between the valve cover and the air filter. The signal goes through the climate control in the dash (don't ask me why) which has the relay. Hi/low goes through a power resistor bolted to the body just to the left (looking towards the back of the car) of that AC cylinder thing with the sight glass on top (forget what its called).

__________________
5 speed '91 190E 2.6 320,000 mi. (new car, fast, smooth as silk six, couldn't find any more Peugeots)
5 speed '85 Peugeot 505 2.5l Turbo Diesel 266,000 mi. (old car, fast for a diesel, had 2 others)
5 speed '01 Jetta V6 (new wifes car, pretty quick)
5 speed '85 Peugeot 505 2.2l Turbo Gas 197,000 mi. (wifes car, faster, sadly gone just short of 200k )
5 speed '83 Yamaha 750 Maxim 14,000 mi. (fastest)
0 speed 4' x 8' 1800 lb Harbor Freight utility trailer (only as fast as what's pulling it)

STOP, DANGER...
That is NOT a safe way to test the fan clutch...
* If there are sharp edges on the blade, it will slice you open.
* If there are serious cracks in the blade, it can shatter and slice you.
* If the clutch is seized to the shaft, it will not stop...

Use compressed air or a garden hose, spraying against the fan rotation.
The attached drawing should make the procedure clear.


Have a great day.

Attached Thumbnails

 

__________________
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Noise Vibration and Harshness (NVH).
Dynamometer.
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1985 300SD
1983 300D
2003 Volvo V70

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People forget how dangerous it can be when working on cars. A damaged fan can send metal through the hood if it breaks, now think what it can do to your hand......

Please be carefull.

Umm sorry??? But that's what my mech did. He just reached in and stopped it with his hand. but I guess he could already tell that the clutch was gone, so he was just demonstrating.......

I don't quite understand the garden hose method - does that actually stop the fan???

I know your mech did it, and he got very lucky.

You don't have to even rev the engine very much to get a piece of metal through the hood. I always stand away from the fan even when checking ignition timing.

!!!

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1989 300E 144K

Try this - with the rear end jacked up off the ground, stuff your hand as far up into the driveshaft tunnel, making sure to have as much contact between your arm and the DS as possible. Have an assistant hop in the car, throw it in gear, and floor it...

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1989 300E 144K

...or try doing what a friend of mine did, jump start a car using a good battery turned upside down on top of the dead one. It almost cost him his eyesight when they exploded on his face.

Post #9 and #10 are lethal...

On the same level of intelligence as

www.darwinawards.com

http://urbanlegends.about.com/od/darwinawards/

I've always used a rolled up newspaper to test the fan clutch on various cars i've worked on.... much safer!

__________________
Ben

'85 500 SEL
'85 928S2
'88 560 SEC
'90 750i

LOL!

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1989 300E 144K

I wouldn't recommend trying to stop any fan with your fingers. However, I have stopped the light plastic ones on the M103 and 104 with my fingers many times. Their pretty much harmless at idle. I would definitely not suggest stopping a M117 or M119 cast aluminum fan with your fingers. Those fans are too big and scary for me!

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Current Stable:
01 ML55 AMG
92 500E (a few mods)
87 300E (lots of mods)
00 Chevy 3500HD Diesel Box Truck
68 18' Donzi Marine
06 GT i-Drive7 1.0 Mountain Bike (with GPS!)

PREVIOUSLY OWNED:83 300SD, 87 420SEL, 88 420SEL, 90 420SEL, 86 560SEL, 86 190E 2.3-16V AMG, 94 E320

The M103 uses a normal viscous fan clutch, non locking. Basically once you hit 2000+ RPM the clutch is over taken and slips totally, it can only spin that fast. Too see if the clutch is still working you need only warm engine up to 100 and it should be fully engaged and spinning at engine speed. Not free wheeling. You can then rev the engine and see if the speed increases forcing more air until you pass 2000 RPM where it will basically just be free wheeling pretty damn quickly. If the fan does not spin faster as you rev the engine than it is most likely the clutch that is dead. This is not a full lock magnetic clutch like on the M102. You can also shut the engine off at 100 degrees and try to spin the fan, if there is resistance then the clutch is at least partially working, if you can spin it with one finger and it keeps going then clutch is most likely dead.

A news paper rolled up and tap the top of the fan will accomplish the same thing as grabbing it but with less of a possibility of finger tip loss.

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....