240D Dilemma

Good Day All,

I have owned a '79 240D for about a year now and am in love with the car. I bought it from the original owner who probably serviced the car to about a 5 on the old 1 - 10 scale. It's got about 240,000 miles on it and looks brand new!

My dilemma: I know it needs a Transmission, (automatic), slips a bit in town and shifts real sluggish. There's a couple of pretty good oil leaks that account for at least half of it's oil consumption, (1 qt. @ 500 miles). On the highway it seems like it'll run forever! My confidence in the car blossoms as it cruises well at 70-75 MPH. The problem is around town. It seems to smoke quite a bit and idles with a rhythmic Chug, Chug, Chug. Most recently after a 500 mile round trip to Vermont it started making a Clack, Clack, Clack the sounds like it's coming from the top end near the front cylinder. This clack seems to all but go away at 1,000 RPM and above and the engine smoothes out nicely.

Could this all be answered by a thorough service? Valves, Fuel Timing, etc? I don't want to sink a ton into her. At that point I would upgrade to a 300DT.

When it's hot, how much smoke should be present when I open the Valve Cover to add oil? Is this a symptom?

Thanks for your help.

[muybweno]

Here are the possibilities that causes excessive oil consumption. these are take directly out of my mechanics mercedes training book...
1. external oil loss (sump oil pan)
2. Ruptured diaphramn in vacuum pump
3. Damaged valve stem seals.
4. Valve guides worn beyond specifications
5. Excessive cylinder and/or piston ring wear.

As for the clattering on your 240D....could possibly be your injectors...when did you last change them out? I know that if your injectors are leaking or bad, then the glow plugs might get destroyed which could lead to a long delay on the pre-glow system. Here are the possibilities for excessive engine knocking
1. Air, water or dirt in fuel system
2. Inferior fuel quality
3. Pressure valve holder over torqued (renew copper seals rings
4. Injection nozzles fouled or opening pressure incorrect.
5. Depressed connector of injection lines (Reduced inside diameter
6. Injection pump timing incorrect
7. Inadequate compression
8. Broken pressure valve.
9. Valves seated too deep in cylinder head
10. Injector nozzles over torqued in head

thats about it...if you solve your engine knocking....chances are you'll solve your smoking problem. Also check your timing chain and tensioner...When was the last time you changed these things? The chain is supposes to last 60,000 miles. If the chain is advanced, you'll get heavy smoking emissions at idle. I just replaced my timing chain and readjusted the valves for the first time....my 300D 1978 work like a charm and it has 285,500 miles on it. My dad is the first owner too

Good luck and i hope this info helps you out