Ok bought my first mercedes diesel today, well traded for my vw diesel pickup... I know abosolutely nothing about mercedes. the car is a 1980 300sd turbo diesel. Has minimal rust but has many other problems that i need help with.
1. the speedometer works, but above 25mph it makes the loudest vibrating sqealing noise. So suggestions here.
2. the odometer hasnt worked for a while...
3. the tachometer doesnt work...
4. no fan at all on the heater, no matter what buttons i push...
Ok now what are somethings that i should know about that tend to go wrong, or that are good to upgrade. Also what can i do to get the best mpg possible...

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1987 300D(Erma)- #14 head, 193k
2003 TDI Beetle sold
1985 300sd sold
1987 300D(Ursala)- #14 head, 157k when sold
1987 300D(Wilbur)- #14head, 356,000+miles, sold after 7 days of owning it.
1992mercedes 300d- totaled and in a junk yard somewhere..
1983 mercedes 300sd- scrapped
1980 mercedes 300sd first mercedes diesel-sold

if it's a loud unbearable Screeching noise, you'll need to oil/Grease your Speedometer cable.

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hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

yes it is a loud unbearable noise so i will oil it and see how that works. My biggest concern is what to check with the heater controls, because i really cant drive it this time of year without defrost...

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1987 300D(Erma)- #14 head, 193k
2003 TDI Beetle sold
1985 300sd sold
1987 300D(Ursala)- #14 head, 157k when sold
1987 300D(Wilbur)- #14head, 356,000+miles, sold after 7 days of owning it.
1992mercedes 300d- totaled and in a junk yard somewhere..
1983 mercedes 300sd- scrapped
1980 mercedes 300sd first mercedes diesel-sold

Check fuses, you may get lucky on fixing the heater fan. There are many posts on here about the fan.
x2 for lube speedo cable
there are posts on here about odometers not working .
There is a lot about tacho's on here, do a search.
Make sure you change the oil regularly & change the fuel filters.
The valve gaps need setting regularly
make sure you always allow it to glow before starting, especially in the cold.
If you plan on using WVO expect trouble. Many of the head ache's on here are related to that.
Read the owners manual.
Change the trans fluid if it hasnt been done lately.
Have fun with your Merc, they are great cars, & will run nearly for ever if you look after them.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

The tach is probably the amp.
The heating issue could be a number of things, but that has the dreaded servo unit.
Good luck.

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83 SD

84 CD

what is the "dreaded servo unit"

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1987 300D(Erma)- #14 head, 193k
2003 TDI Beetle sold
1985 300sd sold
1987 300D(Ursala)- #14 head, 157k when sold
1987 300D(Wilbur)- #14head, 356,000+miles, sold after 7 days of owning it.
1992mercedes 300d- totaled and in a junk yard somewhere..
1983 mercedes 300sd- scrapped
1980 mercedes 300sd first mercedes diesel-sold

Search evil servo, and you'll find plenty of reading. It's a Chrysler thing, and I have no idea why Mercedes would use such a device.

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79 MB 280 SEL Euro 133k
77 MB 450SL 154k
05 Mustang GT Vert (3) 104k
12 TSX Wagon Tech (66k) (192k)
06 Subaru Outback base (135k) 164k
16 Acura MDX (109k) 111k
18 Silverado 2500 LTZ Midnight (212) 56k
97 Ford Ranger 163k
11 RAV4 154k
01 Escape 173k
04 Honda Pilot 292k
1967 Mustang (Resto Project)
1968 Mustang (Parts Bin)
00 Ford Ranger 124k

few more questions...
Where can i find replacement gears for the odometer??
Also i havnt tried to start the car cold cold yet, but even if it is still warm it doesnt just fire right up, it cranks over 2 or 3 times before it starts, is this a vacum related issue, or what should i look for???

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1987 300D(Erma)- #14 head, 193k
2003 TDI Beetle sold
1985 300sd sold
1987 300D(Ursala)- #14 head, 157k when sold
1987 300D(Wilbur)- #14head, 356,000+miles, sold after 7 days of owning it.
1992mercedes 300d- totaled and in a junk yard somewhere..
1983 mercedes 300sd- scrapped
1980 mercedes 300sd first mercedes diesel-sold

you should post your location. You might get lucky. A "bored" forum member who wants to pass along his\her knowledge to you might live within 5 miles.

I've got several parts cars.....

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daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
Cluster Needles Paint
New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

I'm not too familar with the SD's but I know in my 85 there's an over volt protection fuse that runs the tach. If the SD's have it might as well take a look.

The servo I believe is made of plastic and lives inside the engine bay. From my searching it appears that the constant heat and freezing causes the unit to crack.

I'm guessing the solution is to replace it or find a manual climate control system. Either way it's a pain in the butt

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-Typos courtesy of my mobile phone.

I live in circleville ohio, which is just south of columbus... I will work on putting this in my signature.

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1987 300D(Erma)- #14 head, 193k
2003 TDI Beetle sold
1985 300sd sold
1987 300D(Ursala)- #14 head, 157k when sold
1987 300D(Wilbur)- #14head, 356,000+miles, sold after 7 days of owning it.
1992mercedes 300d- totaled and in a junk yard somewhere..
1983 mercedes 300sd- scrapped
1980 mercedes 300sd first mercedes diesel-sold

The 84 and 85's used a different tach set up.
A friend has the dreaded servo unit, new METAL servo and "new" amp, still doesn't work, so I'm suspecting the "new" amp isn't.

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83 SD

84 CD

Yeah I thought so Worth a comment though.

They make evil metal servos? Are they still evil if they don't crack

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-Typos courtesy of my mobile phone.

Well i opened the fuse panel and all of the fusses were corroded, and several were actually burnt in half... So after replaceing them all, i now have a blower fan, windshield wipers and spray, intrument cluster lights and operation, and best of all...glowplugs... Now the only thing left is too fix the noise in the spedometer and odometer. And the motor mount... the motor mount came in today, and i got the engine lifted off it, but the mount split in half and im having trouble getting the alenheads off... other than that she runs and drives great

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1987 300D(Erma)- #14 head, 193k
2003 TDI Beetle sold
1985 300sd sold
1987 300D(Ursala)- #14 head, 157k when sold
1987 300D(Wilbur)- #14head, 356,000+miles, sold after 7 days of owning it.
1992mercedes 300d- totaled and in a junk yard somewhere..
1983 mercedes 300sd- scrapped
1980 mercedes 300sd first mercedes diesel-sold

^ Sounds good.

ok... I didn't know they made 'em myself, a friend mentioned that.

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83 SD

84 CD