[GermanCarNut]

Going to look at a 300D tomorrow. I've wanted a Mercedes for 10 years now, but high school and now college seem to have gotten in the way! The price is right on this one, so I've got to at least look at it!
Anyway, the car has 182,000 miles. I know all about MB diesel longevity from reading the posts here, and looking at the mileage on the cars in the classifieds, but I still think it would be a good idea to check the compression. HOW do you do this on a diesel? Through the Glow Plugs?? In the forum everyone always says: "Check the compression", but no one ever says how... Obviously a guage, but where do you find one that goes up to 300+psi? These 3.0 5cyls. should develope 320psi with a variation of no more than 25psi, correct? I am mechanically inclined, I just don't know how to do it on a diesel and cannot find any info regarding the procedure, particulary on a MB Turbodiesel.
What is the best way to check the turbo when I look at the car?
Also, what are the typical "soft spots" of a 123? Where do I need to look to aviod getting a hidden rust bucket? I don't mind changing out parts, but when th body is gone, there is no going back.
Any other thoughts before I look at her would be greatly appreciated.
Thank you!
-Brian

 

[wdba123190]

Hey Brian,
Where is the car exactly? I'm down in Fredonia, but I mihgt be headed up to ...

Hey Brian,
Where is the car exactly? I'm down in Fredonia, but I mihgt be headed up to Rochester next week if you wanted help looking for soft spots. BTW, how much do you want for the 4spd? I might be in the market for one. Worst places for rust (as in they will be there on that car if it's been up here for more than a few years) are the rocker panels right behind the wheels, under the seats (if you see any floor rust there it's probably worse than it looks, MB under coating will hold up a whole rotten floor. very easy to fix, but where the water's coming in may not be so), drains under hood near hinges, and behind the battery. I just patched a hole I could put my fist through into the cabin behind my battery. Read old posts here about purchases. Trannys temd to go, as do heating/climate control systems. Good Luck!
-M-

 

[Ler]

Someone either here or on another forum suggested that you can check indirectly by looking...

Someone either here or on another forum suggested that you can check indirectly by looking for blowby- remove the oil filler cap with the engine running and look for smoke escaping.

I've never tried this to know if it's valid, but maybe someone else here can chime in.

 

[dfwdiesel]

A really good engine will let you open the oil cap while running with a good long sleeve s...

A really good engine will let you open the oil cap while running with a good long sleeve shirt on.

But many engines with a great deal of blowby still run well and can have 100K plus miles left.

1985 is considered the best 123 300D by many. 82 to 85
have the nice extra kick of a turbo. But if an ultra clean non turbo turns up, I would go for it. One of the favorite 123's in my fleet is a 78 silver 300D.

In addition to the trans, and the HVAC controls, also look at the front end, especially bushings and lower ball joints, there pricey to pay some one to install and are beyond the average DIY.

I would rather RR a trans or deal with the HVAC system then rebuild a front end.
John Gregg