Lad:

Blue smoke on takeoff after idling means oil is leaking past the valve guide seals. On a freshly rebuilt engine, I'd suspect a poor valve job, especially if the rebuilder wasn't familiar with MB diesels. Off idle, these engines can comsume vast quantites of oil with no smoke at all -- just fuel, after all, only a little thicker than diesel fuel!

If it takes a couple glow plug cycles to start in cold weather, your compression is low, most likely due to tight valve clearance. Get your valves adjusted, or do it yourself -- intakes are 0.005" and exhaust is 0.016". Instructions are available in several threads on this group. MB diesels are very sensitive to inadequate valve clearance, and it always goes down! They need to be checked and/or adjusted every 15,000 miles without fail.

20-23 mpg is rotten for this car -- should be getting upwards of 28, as high as 32. Cold weather is hell on the injector overflow lines -- black fabric covered hoses between the injectors. There is a plug in a short one on one end, the other goes to the fuel filter houseing overflow line and back to the tank. If these lines leak, you can spill a terrific amount of fuel -- you can usually smell it. Don't use anything but MB overflow line -- ordinary vacuum hose will swell, soften, and leak. It's kinda expensive, but I've not found anything else that works well. You won't see fuel on the ground -- it evaporates off the engine.

Check the valve stem clearance while replacing the stem seals (or having it done) -- try to rock the valve sidways while lowering it off the seat a bit -- perceptible motion means the valve guide is shot. A terrible problem with american machine shops -- they always want to replace the bronze exhaust valve guide with a steel one because it is "better" -- it's not, of course, because these are sodium filled valves and get MUCH hotter in operation that a simple steel valve -- the bronze guide expands fast enough that the valve won't get bigger than the hole. Most shops also want to ream the guides out to give 2-3 thousandths clearance, which will allow vast quantities of oil down into the cylinders. If the valve goes in, oiled, and can be foreced up and down, it has adequate clearance. It isn't usually necessary to ream MB guides at all 00 the fit from the factory. If the valve stem clearance is too high, you need a valve job -- guide replacement and new seals, maybe valves ground, possibly new exhaust valves -- people tend to "save" money by not replacing them and selling the car -- new exhaust valves are $45 each. They won't last, however, so it isn't saving money to have to do the job over again after 30,000 miles!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!