Hello,

I'm new to these forums. I've never owned a MB. I really like the w123 diesel models. I'd like to own one. Ideally, i'd want to find one thats in good enough shape that i wouldn't need to spend a lot on repairs. The only place i can find them is on craigslist. Can someone with experience in this area advise me on what to look for?

Thanks,
Nick

 

The truth about these Cars is that if you cannot fix the Car Yourself it can become a Money Pit very quickly.
You also need to take a very special interest in learning what is needed to keep it going in a short period of time.
One of the most neglected items is that the Valve need to be adjusted and owners that could not do it themselves did not want to pay to have it done so it never got done.

These Cars have a lot of Rubber parts on the Suspension and Drive Train that are 25+ years old if they have never been replaced; just waiting to fail.
A Car can be in extremely well maintained condition and have a Coolant Thermostat Stick or an Oil Cooler Hose give out. That overheated Oil starved Car might be sold on the Craiglist.

What People like to see when they are looking to buy a Car is one that had few owners and one who kept all the records on the maintenance, repairs and Parts that went into it.

You need to physically get under the Car and look for Rust and open the Hood and look for rust on the Fire Wall, the area the Hood Spring retract into and around and below the Battery tray.

The Automatic Transmissions seem to Me to be more problematic than any of the Cars I have owned with Auto Transmission since I started driving which was around 1968.
The Climate Controls seldom work properly.
The Door Locks use Vacuum to actuate them. Not terribly hard to trouble shoot but because it is unique you have to learn about it.

My own Mercedes has not been a particularly bad Car compared to some I have read about but I believe I have done more Mechanical work on it in a shorter time then I have on any other Car I have owned.

The above stuff is sort of the tip if the Ice Burg so to speak.

 

One of the biggest issues with buying a used 123 series is related to engine compression because unlike a gas engine it is not easy to determine if the compression is within limits without performing a compression test. Just because 1 car you look at has 100,000 miles and another has 200,000 doesnt automatically mean that the lower mileage vehicle will have better compression and thus last longer. I would suggest that you buy from someone who is knowledgeable about the car. If they have owned for less than a year I would avoid the car, this is typically someone who gets in over their head and does more harm than good while operating the car. What weight oil do they use? Ask to see the bottle, if it isnt diesel rated oil, I would move on. The factory under coating holds water and causes the metal to rot away while leaving the factory under coating virtually undisturbed. Get under the car and literally smack the floor boards under the drivers seat and passenger seat areas, if it moves at all, move on. Inspect the rear fender well behind the rear tire, as well as the front jack point areas as these are know rust problem areas. Small holes can be repaired but if you find major corrosion avoid the car. Cars with over 150,000 typically need new front and rear crankshaft seals, some seepage is normal but if you find excessive leaking move on as these repairs will be costly. With this being said these are one of the greatest cars ever built and working on them is an absolute joy, bolts were installed with anti seize at the factory as well as thread locker where required. Use quality replacement parts, take your time when doing repairs and enjoy a fine German automobile. It wont be perfect when you buy it but with a haynes manual and some effort you will have a great car. If you find a potential vehicle you might post info about it and ask for support. Give mileage, price and any other details and ask for help. Mercedes Diesel Owners are generally helpful, quirky individuals who are CRAZY about their diesels.

 

Just take your time and let the car "talk to you". Fire her up cold after looking for anything abnormal. Let her sing her song. If she's out of tune, you will know. Blow by test with the oil cap, check everything power related. Parts are not cheap and getting tricky to find. Some of these cars have been sitting awhile when diesel went sky high, and diesels need to run hard. They hate sitting dormant. These cars were basically fancy work horses back in the day. The family that took very long trips, commuted long distances, and ran hard. Keep in mind, diesel mixtures have changed in the last 30 years and this new stuff gums up pretty quick, so check all fuel filters. Pop the air intake tube off the turbo, check for play and oil seepage... Don't listen to people that say the turbos rarely go out... I've replaced a couple in various om617 motors, and it's getting to be the end of their life. But, find a good one with a lot of documentation from somebody, and you are golden. These are not hot rods by any means. The ones on YouTube drifting in Russia have a ton of "mob" money in them. For that kinda money you can get an AMG or a 24v cummins... Or both!