My 99 606 has been making a groaning noise when you turn the headlights on at idle, it gets louder when you turn the fogs on or turn the wheel. When you shut the lights off the groaning noise goes away. I have to assume the alternator pulley or bearings are going bad but I wanted to see if someone else has been down this road.

I have had no charging issues and the car runs fine besides this annoying noise.

Motor mounts replace 6 months ago, car has 189k

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

Check all pulleys, P/S fluid and filter.

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Present
1987 300SDL
1991 300SL
1990 560SEL
2001 ML320

Past
1969 200D 1979-82
1983 300SD 1984-85
1972 250C 1982-02
1995 S350 2011
1997 S320 2012

Power steering fluid is on my list for replacing along with the filter that I have read is very hard to see.

My problem appears to be coming from the alternator pulley or alternator itself as I placed my stethoscope on top of alternator and I can hear the droning groan louder.

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

Have any coolant loss issues lately? Often the water pump drips onto the alt, prematurely waxing it.

no coolant leaking, but the water pump is going to get replaced this summer along with the coolant, T-stat and hoses as maintenance.

I think I am going to replace the PS fluid to see if it helps. I noticed a power steering filter listed as a part but I am not sure how to change that.

As for the fluid I will suck out what I can multiple times while turning the wheel lock to lock several times.

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

I had a similar problem and it caused a failure of the belt tensioner. Turned out to be the alternator - so the sooner you address the issue with the alternator the cheaper.


Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Jim-

Is there a way to rebuild it or did you just buy a new one?

__________________
1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

By the time I reacted I had to buy a new one - actually traded the old one for core value - and had to put a new belt tensioner in at the same time.

Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

After further inspection... I had a friend come over and help with the groan inspection, one to man the headlight switch while I use the scope. I noticed the pulley on the water pump to be wobbling like its bent slightly. It is enough to notice but its not making the belt jump. I placed the scope on the water pump housing and the groan seems to be coming from the water pump as its louder then when I place it on the alternator. Or its just making it sound like its the water pump pulley and its really the alternator-either way I need to do this maintenance.

I think my game plan is to do my coolant maintenance now instead of waiting until summer like I was planning. Replace water pump, pulley, t-stat, coolant and both hoses. If the noise is still there then move on to the alternator.

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

This makes sense since there's more side load on the WP pulley as the alternator load increases.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

just to update in case someone else is searching this issue.

Replaced the water pump, coolant flush, t-stat and housing and both hoses. Water pump bearings were shot, you could hear them turning it by hand. What I did not order was the belt tensioner pulley and as I discovered it was making rattling noise when I removed it so I replaced it as well as the fan clutch as it was leaking fluid and original.

All back together and the noise is still present, although quieter. It is the
alternator pulley as well so I am sure the bearings are bad. I am ordering a new alternator now, 115amp version. I guess a 190,000 miles is enough to ask of a alternator. it may have been the alternator bearings dragging that caused the water pump and belt tensioner to go bad as well, who knows, but at least I have it all sorted out now.

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

The belt tensioner on my 95 was totally shot. Search this forum for my recent post on this. Dont neglect this. Easy to evaluate while you're in there. Check status of the tensioner arm and make sure the pivot pin isn't damaged.

My 95 groaned too. I didn't positively Identify the issue but it hasn't since I replaced the thoroughly worn down voltage regulator - another easy fix.

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2009 E320 Bluetec 117,000
1995 E300D 306,000 Sold
1996 Ford Taurus LX 130,000 Sold
1985 300TD Still 225,000 Sold
2016 Ford Fusion 24,900

Tensioner is already replaced, and it was bad. If your saying the groaning stopped after a regulator replacement maybe I should cancel my order for the alternator and just get the regulator

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1999 E300 TD 190,000
1996 Passat TDI 225,000-sold
1996 E300 120,000-sold
1998 Jetta TDI 186,000 -sold
1983 Chev Suburban C20 6.2-sold

The Alternator "Slip Rings" (The VR's brushes contact them for transmission)
along with the Bearings of the alternator itself probably need replacing.

These Two remans should tell you all you need for Bosch Alternator rebuilding:

Oichan's Corrado Alternator Rebuild.

Alternator Bearing Replacement in a W140 Mercedes

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'84 300SD sold
124.128