Sounds like I have either a ghost or a small dog howling at the moon in the '91 300SE.

Coming from the front of the engine when cold at fast idle; goes away as engine heats. Also hear the same thing (I assume) when driving at 2500 in any gear; moans under load, stops immediately when I let off the gas.
Not too loud, but noticeable. Done it for months, no apparent detrimental effect - YET.

I know what it's NOT:
- NOT THE FAN CLUTCH - took the whole fan/clutch assembly off and it still did it.
- Not the air smog pump - disconnected
- Not coming from any of the fan-driven accessories - took the belt off, still did it at cold fast idle.

Anyone ever had one of these "haunted" 103's?

DG

Power steering pump?

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

Could it be engine mounting related?

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Have you checked the bearings in the distributor? My 560SEL sounded like that right before the distro went out.

__________________
-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition

Argh, that's one of my dumber suggestions since the M103 doesn't have an actual distributor per se, just that cam shaft attachment. My next guess would have been water pump, but you said you ran it without the serpentine...

I'll poke around in my 300SE when I get home and see if I can think of anything.

__________________
-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition

Well, I looked my 300SE up and down last night, and I am at a loss as to what could make that noise from the front end, even with the serpentine belt off.

Unless it's timing chain related, I'd still pull off the distributor and check that the back cover, the red plastic disc that "seals" to the back of the distributor cap hasn't broken or otherwise found itself scraping against the camshaft. There's also the camshaft seal on the timing cover, but I'm really grasping at straws here.

One thought I had was that your EGR is leaking and making an exhaust whistle, but I have to think you'd have located it if that were the case.

I mean, you took off the serpentine belt, right? What is left spinning after that? The cranksaft, the camshaft, the oil pump, the distributor, and that's pretty much it, no?

__________________
-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition