something on my m103 engine sounds kinda rough, I think it may be the fan- when you turn it by hand, after about half a turn there is some resistance then moves smoothly again and so on.

When the engine is running it sounds like if you were to apply some resistance to say, an electrical motor, say holding your hand against it, then let go again , if that makes any sense!

the noise comes from the fan/ accesory belt area at the front of the engine.
I have a new belt and tensioner, engine is running good (no misses, smooth idle etc).

any ideas?

__________________
1993 320TE M104
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past:

1983 230E W123 M102
1994 E300D S124 OM606 (x2)
1967 250SE W108 M129
1972 280se 3.5 W108 M116
1980 280SE W116 M110
1980 350SE W116 M116
1992 300E W124 M103
1994 E280 W124 M104
----------------------------------------------
"music and women I cannot but give way to, whatever my business" -Pepys

The engine with or without the fan doesn't turn smoothly. It gets more difficult as a piston crests then it helps you when the piston is past the crest. There shouldn't be any scraping, though.

Sixto
95 S420
87 300SDL

If you meant the fan, then it's probably bad. Is there any wobble? If so, get it out of there IMMEDIATELY. A fan that comes off it's mount will feast on your radiator.

Sixto
95 S420
87 300SDL

thnaks for the info- there's no scraping, i'm thinking maybe the noise could be bearings in one of the items driven by the accessory belt?

__________________
1993 320TE M104
---------------------------------------------------
past:

1983 230E W123 M102
1994 E300D S124 OM606 (x2)
1967 250SE W108 M129
1972 280se 3.5 W108 M116
1980 280SE W116 M110
1980 350SE W116 M116
1992 300E W124 M103
1994 E280 W124 M104
----------------------------------------------
"music and women I cannot but give way to, whatever my business" -Pepys

sixto- just saw your 2nd post. there's no wobble or scrape. the fan is the (newer?) plastic type.

__________________
1993 320TE M104
---------------------------------------------------
past:

1983 230E W123 M102
1994 E300D S124 OM606 (x2)
1967 250SE W108 M129
1972 280se 3.5 W108 M116
1980 280SE W116 M110
1980 350SE W116 M116
1992 300E W124 M103
1994 E280 W124 M104
----------------------------------------------
"music and women I cannot but give way to, whatever my business" -Pepys

Disengage the belt from the tensioner, no need to remove the belt completely, and check the pulleys one-by-one.

Sixto
95 S420
87 300SDL

Are you sure the fan is not rubbing against the fan shroud? The motor mounts may have collapsed enough to allow contact.

The fan shroud is adjustable up and down, BTW.

__________________
2012 E350
2006 Callaway SC560

There is a bearing behind the fan. It is a common failure item. The replacement part is the carrier and bearing assembly.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe