There is some sort of noise coming from the engine compartment at higher rpms on my '85 300d turbo and I'm not exactly sure what it is. It happened right before the alt locked up and all that stuff so I thought when I replaced the alt and all the belts it would go away, but it persists. It sounds normal about 2500 and below but when I get above that it sounds like a high pitched noise, almost like a whistle or hissing sound (I thought maybe turbo?) but it could be fan noise like it's spinning too fast or something. I recharged the AC and put some leak sealer in there while on my trip and noticed it shortly after that so maybe it could be that, but I just don't know. The AC did work great for about an hour before it started blowing hot again. Here's why I suspect the fan or the clutch.

The fan spins freely without the engine running or any belts turning it (this could be normal I'm still a noob. Isn't there a clutch that's supposed to keep that from happening?). When I took it off to replace the belts it only had 3 screws holding it on to the pulley and the threads were all jacked up like it was loose at some point and there is some key holing on the pulley from that. I wish I would have taken pics. I did open the hood and pulled the throttle linkage to rev the engine. I could hear the sound, but couldn't pin point it. Any Ideas? Fan or something with the AC compressor? Hopefully it's not about to lock up and shred the new belt I just put on there. I doesn't sound like grinding...

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1985 300d smoke silver/red int. (204k) <--Sadie the 80's Mercedes from Hades!
1985 300TD 587 cabernet red/155 Creme (143k)
2007 Ford Expedition EL (54k)

"Seems to me you bought a hobby... not a car" - My dad.

A clutch fan will turn without the engine running, so that sounds normal.

Those screws are cause for concern tho.

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83 SD

84 CD

Power steering pump?

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Cheers!
Scott McPhee

1987 300D

not sure. Checked fluid on PS. It has ATF in it and had enough. It doesn't quite sound like PS pump. I had 2 go bad on my grand am. I heard it or a sound like it today at idle when I got to work but this time the sound was coming from the passenger side of the car under the dash. I'm thinking maybe something with the A/C or a vac leak under the dash. My A/C hasn't worked that well on this car ever so maybe it's a normal sound. When I shut the car off I heard the sound kinda fizzle out and had an almost bubbly sound to it. I bought some UV dye to look for leaks in the A/C and will look into that today. I just had a thought though as I'm typing this. BRB. going to check something.

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1985 300d smoke silver/red int. (204k) <--Sadie the 80's Mercedes from Hades!
1985 300TD 587 cabernet red/155 Creme (143k)
2007 Ford Expedition EL (54k)

"Seems to me you bought a hobby... not a car" - My dad.

AHA! I noticed a slight lack of power as well, but wasn't linking them together until now. The sound did seem to get quieter as time went on then I remembered that a month or 2 ago I was doing alda service and I broke the pressure line at the banjo bolt. I put a section of rubber hose over the parts to keep them going while I got a replacement. Then I did the front end rebuild, went on the trip, had a breakdown and completely forgot about that until I was typing a few minutes ago. The rubber hose has broke in 2 and the pressure hose is now disconnected and dangling behind the valve cover. I bet a small hole formed in the rubber hose and made it sound terrible at first and then after it ripped away and there was a bigger hole for the air to escape it lessened the sound. Looks like I need a new pressure hose.

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1985 300d smoke silver/red int. (204k) <--Sadie the 80's Mercedes from Hades!
1985 300TD 587 cabernet red/155 Creme (143k)
2007 Ford Expedition EL (54k)

"Seems to me you bought a hobby... not a car" - My dad.

Sounds like, not expensive.

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83 SD

84 CD

Replace the pressure line with a bendable copper line with rubber connectors at either end. It's less likely to break.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I replaced my pressure line with 5.00mm OD stuff.
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=MBZ&please_wait=N&forumid=&threadid=&command=DWsearch&description=vacuum+line&I1.x=0&I1.y=0

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83 SD

84 CD

I actually found something at advance that works fine. It's hard emission line and has nearly the same inside diameter, but the OD is a tad thicker. I put it in there and the noise is gone and the power has returned. It was 4.99. As soon as I fixed that now my vacuum is all screwed up. It seems like everytime I fix anything somthing else will break. I guess that's what I get for buying an 1100 dollar car. I still love it though!

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1985 300d smoke silver/red int. (204k) <--Sadie the 80's Mercedes from Hades!
1985 300TD 587 cabernet red/155 Creme (143k)
2007 Ford Expedition EL (54k)

"Seems to me you bought a hobby... not a car" - My dad.

please define "spins freely" can you push the blade and when you let go it keeps turning? that's BAD and must be replaced before you loose you hood and radiator!

just easily pushing, but not freewheeling is fine, and normal.

if the threads are "jacked up" on the water pump hub, you should change it, and replace the missing bolt.
if it's the bolts that are damaged, you need to replace them all, and likely the water pump as well...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Sounds good.

Yeah, these cars will keep you on your toes!

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83 SD

84 CD

It doesn't free wheel. It just moves if I'm pushing it around. Its just the bolt threads that are messed up I believe. I need to get some more bolts. I was ordering stuff the other day but I keep forgetting about those little things, because it's not making a noise or doing something to remind me it's bad every time I drive it.

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1985 300d smoke silver/red int. (204k) <--Sadie the 80's Mercedes from Hades!
1985 300TD 587 cabernet red/155 Creme (143k)
2007 Ford Expedition EL (54k)

"Seems to me you bought a hobby... not a car" - My dad.