I posted this in the vintage Mercedes forum a day or two ago, and it was suggested I repost here...

Hey guys, I just picked up a 1981 240D that comes with a few expected quirks. This will be an adventure as it is my first Mercedes and first diesel. The previous owner posted here and other places so some history on the car may be available to me online if I can track down his posts.

The car is in overall very good shape body-wise. I was looking at cars that would rate a 4 to 5 on my scale of condition, but for a couple grand more, I decided it was worth it to get a strong body and decent mechanicals and hope it all pans out. I rate this one at about a 7.5-8 on my scale of joy.

What I have noticed so far:

1. Odometer sticks (saw the repair at diesel giant - not too scary) - $0 to fix
2. Engine has blowby - teakettle test had oil spray all over and rad cap really jumping. PO says a valve adjustment will help - I am not sure when the last one was done. Is it worth it to buy the kit, or just the wrenches? Engine may be worn. Not sure. Swap??? - $180 for valve adjustment kit with wrenches, gasket, feeler gauges, etc.
3. Oil pressure gauge is pegged to the top while driving - I don't know what the normal position for the gauge is. Rings shot? Sensor bad? Gauge bad? (Could be pricey - dunno)
4. The dash is all original - including radio. But no lights work except the dim speedo bulb. I think I can get bulbs for the heater gauges, but how do you light up the radio? - $20 in bulbs
5. Power windows don't work for the back seat. Any common problem I should know about there? - No idea, likely an electric fault
6. Driver's door lock has vacuum issue (you can hear the vacuum fail when you unlock the door). Not an issue - can fix over a weekend. - $30 part, $30 vacuum tester
7. Power antenna only goes 1/2 way down. any ideas for a fix there? it looks straight, but is pretty gummed up. Last car I was able to just clean the antenna and then it worked. - worst case is replace power antenna - $40
8. The engine is pretty shaky, so it wouldn't surprise me if it needs new motor mounts. - $100 in parts

Are there any recommended checks I should do or have my mechanic do for me while he's under there for the "state" inspection (we're in Canada here, so its provincial). All I could see lying on the ground with a trouble light was possibly a tie rod end, and one strut had a lot of grease around it, but not sure if it was a sloppy lube job or the strut had failed - but I am not a mechanic

Have the mech take a look at the driveshaft flex discs while he's there.

Valve adjustment won't likely affect blowby much but should be done every 15k. Don't follow DGs guide on valve adjustment, look up the guide by whunter on this forum. If you have a problem with the adjustment not going right, stop, ask questions, several of us have either broken valve guides or had mechanics break valve guides from doing it wrong (I'm one that broke my own ().

Compression test is a better guide of overall engine health than blowby, but if the cap is staying on the motor during teakettle and not launching over the fender then it's probably not excessive. Oil spatter during the test is normal.

There's some guides here on what to check before buying/or on just taking ownership. Lots of useful information. Checking timing chain stretch is in there, plus a lot that i probably can't remember as i'm a relative newbie myself.

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Eric, CPO, Submarines, retired.
Here's a sig line...
Mine: '68 Corvette LS1/4L65E, 83 240D, 2000 GMC 4x4, 08 FLSTC Anniv
Hers: '72 Corvette 454/4spd, '99 MB SLK, '93 Metro vert, 78 240D, '92 Silverado, '65 Fjord Rustang, '59 Fjord Fairlane, '17 Slingshot.

Perfectly normal!

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)

Welcome! 240d's are like a faithful dog. I love them and am putting one back on the road right now. I've prolly had 13 of them.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Glad to hear the pressure gauge is in the normal position. I would have expected the halfway mark to be normal. Those crazy germans!

The cap does stay in place during blowby test but man it dances. Also oil going everywhere. In DG's example of the test (without cap in place) there is no oil loss. Maybe I have a healthier car than I thought. Yay!

Driveshaft flex discs - tell me more... going to Google right now. AHA - flex disc how-to and whatzit... http://www.youtube.com/watch?v=4yCxhyTlysw

Once the engine is warm, the needle will drop at idle. But it should be pegged to the top on a cold start and during driving.

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)

I really don't like DG site. It's gotten me in trouble a couple of times before finding this forum. His odo fix is wrong, do not use superglue or loctite as he shows. Valve adjustment is wrong, the lobes point to the oil squirter rail not straight up. Oil flies everywhere on a OM616 and 617 tea kettle test.

When the engine is hot both of mine still peg the needle off idle, and are slightly below half at idle. Perfectly normal for these.

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Eric, CPO, Submarines, retired.
Here's a sig line...
Mine: '68 Corvette LS1/4L65E, 83 240D, 2000 GMC 4x4, 08 FLSTC Anniv
Hers: '72 Corvette 454/4spd, '99 MB SLK, '93 Metro vert, 78 240D, '92 Silverado, '65 Fjord Rustang, '59 Fjord Fairlane, '17 Slingshot.

That Video is a good one, but they didn`t mention the front Disk at the Transmission. This one fails more often than the rear Disk. Cracks or pieces of string showing, replace it NOW.
Also loosening the 46mm large nut on the drive line, and the 2 bolts that hold the Center Support bearing will give the DL some room to move when prying the Disk off.

They all don`t come off that easy, some are rusted on, and have had to spray them down with Kroil and let it soak for a while.

Here is a good video showing what can happen if you let one come apart.
BMW EPIC flex coupler FAILURE! rip apart chassis - YouTube

Do not buy URO Parts. I think it was Bodyart27 that replaced his suspension parts on his 560SEL. 9 months later the front Disk came apart, ripped up his tunnel, DL, Transmission and set off his Air Bags.

There is an ongoing thread here on the URO parts.

The Craftsman 40811 that DJ shows is $7 - $12 depending where you buy one.
and the VC gasket is $4.50 here on Pelican
1981 Mercedes-Benz 240D Base Sedan - Filters & Belts - Page 3

There is a bunch of valve adjustment threads and Whunter (Roy) has put them together is a DIY resources area.

You can make the 14mm bent wrenches or look on E-bay or CL, and they come up from time to time. sometimes you can score on a cheap set of Hazets. I scored several yrs ago on a 5 wrench set of MB`s for $58.

Your Odometer/Trip not working is the Pot metal gear slipping on the shaft. An easy fix, just have to remove the Cluster from the dash and remove the Spedometer. Then take it apart. DJ is a good guide.
I had one from PNP that was my sacrificial lamb to dissect to understand what did what, and how to get the numbers to line back up.
Don`t buy a generic spedo off E-Bay that is listed as working, and fits 123`s from 77 - 85. Yes it will fit all W123`s, but the spedo is matched to the gearing of the Differential.

Behind the center console is a thing called the Spider, has one small rice light bulb and a Fiber Optic that goes to the various switches on the Console. there might be a list in your owners manual of the wattage of the various bulbs.
The knobs for the climate control on the 240D use this same bulb. Pull the knobs off and the bulb will be behind it. Use the appropriate wattage or if too large, the plastic starts to melt and distort.

To replace the instrument cluster bulbs, you will have to pull the cluster.
When you hit the PNP yards, start grabbing some spare bulbs.

Your Oil Gauge is normal to be pegged when it is cold at an idle. when it is fully warmed up at an idle should be between 1 - 2 Bars. above about 1300 RPM`s it will peg the needle, even though the oil pressure is around 97lbs.
The idle speed is around 750 RPM`s, so any idle rpm above that will increase the oil pressure reading.


All these engines have some blow by, some a little, and some smoke like a freight train. the more wear the eng has, then the more pressure and gasses that get past the rings etc... as the engine gets hot, there is fumes from the hot oil also that is part of the blow by.
If your VC Cap is leaking oil, the rubber gasket under it can be replaced, think they are a couple dollars. I have used the blue one from the fuel cap, and think it is a bit thicker for a tighter seal.

Engine mounts are about $20 each, again, don't source URO mounts.

The vac system is simple, the green line is for the climate control, yellow for the door lock system and for the Vac tank above the fuel tank in the trunk. the tank is only for the doors, trunk and fuel door lock actuators.
get a Mity-Vac to chase down the various problems.
There are two brown vac lines. one comes off the main black line going to the brake booster from the vac Pump. this brown line goes to the ignition switch, the a brown line goes to the rear of the IP to the fuel shut off valve.

the pwr antenna might just need the plastic cable replaced that moves the mast up/down. or maybe water has got into the inside of the assembly and corroded something.. the side cover comes off.

240`s are easy to keep on the road, kind of like the old Model T Fords, very basic.


Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Thanks Charlie - lotsa info there.

Just heard back from my mechanic. Apparently I have some welding in my future :S I thought I'd looked at all the suspect bits but I guess I missed a couple spots where rust got through.

Mechanic suggested plugging leaks until spring then go on a mission with the underbody before anything serious sets in. Sad because the car looks really clean.