On the M104 engines (in my 1993 300E2.8), is it possible to replace the idler bearing without pulling the radiator and only removing the fan and shroud?

If so, what tools would I need? My bearing is making a horrible noise right now, driving the car is almost an embarrassment.

Yes, it's possible. I saw my mechanic do it, but I can't tell you what tools to use.

When the idler bearing went out on my 1993 300E 3.2, it was making such a terribly loud noise, people would cover their ears when I drove through a supermarket parking lot.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

I pretend that it's the Chevy/Ford/GMC truck in front of me that almost everyone where I live seems to drive.

ok, so it's possible (I thought it might be, just wanted to check) - how about tools, anyone?

I might have a similar problem as yours.

Just wondering does the noise change depending on your engine speed (RPM)? Higher pitched? or does it stay constant?

Mine went up and down with engine rpm.

The bearing on the air pump also went out at a different time, and made the same horrible screeching noise.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

yup, same problem here - I believe it's possible to replace just the bearing, not the entire air pump (I hope so, as remanufactured air pumps are $600+)... can that be done with the radiator in place too? I believe it's in a fairly akward place tucked in close to the exhaust manifold...

Yep, the dealer sells an air pump rebuild kit, which is basically the bearing assembly, and it costs about $200-ish, plus labor to install.

The air pump is removed from the car, the bearing is replaced on the bench, and its reinstalled in the car.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

I tested this last night - the noise stays the same, but the drumming sounds increase in frequency as the rpm's rise.

Removing the radiator on my 94 E320 was the easiest thing I've done on that car.

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TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)

The noise on my car suddenly got a lot louder over the past few days, and it turned out to be the fan bearing that was failing and the fan blades were hitting the belt tensioner.

I was going to order a new bearing and fan blade early next week, but what do I do about the special tool required to remove the fan and viscous clutch? Is there something I can buy or rent that will do the job?

It can be done with a belt wrench on the pulley.

For the belt tensioner, I believe I have to remove the plastic cover and slacken the nut 1/4 to 1/2 of a turn before I release the tension on the belt.

I couldn't get mine to move, and I thought I read somewhere that one of these two is reverse-threaded - which way does this turn?

To remove the fan clutch in my 94, I use a 1+ foot-long 4mm rod bent about 75 degrees the last half inch. Stick it down between the tstat and the block; it fits in a hole on the backside of the flange the fan clutch pulley bolts onto. Now use a long ?8mm allen ($20 set was well worth it--a hex socket is a pain--too long) and a cheater pipe. For the tensioner, it takes a larger hex key--?10mm. I use a 3/8 hex socket and a long breaker bar. It is torqued to a seemingly very high 75 Nm--about 55 ft-lbs as I recall. The job is waaaay easier with radiator removed. The extra inch of room is so nice. I don't recall either bolt being LH thread.

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TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)

Do I need to drain the crankcase before removing the heating water return line that's obstructing the final bolt of the fan bearing bracket?

For the same water return line, the manual says to 'replace seal (27a)' - can I reuse the existing seal if I pull that water line out? If I need a new one, is it a generic one that can be purchased anywhere?

The manual also says for the 124 model that I should 'replace seal (97) in timing case cover' - I didn't see a seal where it's pointing to in the diagram, do I need to worry about anything?

When attaching the idler pulley to the fan bearing bracket, what torque should I have my wrench set to?

Someone must know at least some of the answers - I want to get this car finished and running again today!