Well, a "puff" on hard acceleration may be normal, but I don't know about a "2-3-second belch". That seems to be significant overfueling.

Fred, has the air filter ever been changed? If it's very dirty it would contribute to overfueling. I know from experience that the cetane of the diesel fuel also affects the intensity of the smoke puff on acceleration. My Jetta TDI can lay down a nice cloud if I don't add my cetane booster. But with Chevron's diesel (which is supposedly higher in cetane than most) + my cetane booster I have a hard time getting it to smoke at all.

Check the particulate filter is working correctly, and that you have low-ash oil in the engine (MB 229.31 IIRC).

This statement is most definitly refering to a two stroke diesel, which features weep holes on the block and holes around each cylander liner, effectivly eliminating the need for an intake and exhaust valves as well as those two strokes, making a powerstroke with just one revolution of the crank shaft. The holes that vent air two and from the cylander are pesky because oil can slot through and enter the combustion chamber. These engines were made by detroit diesel mainly, and the weep holes on the blocks helped to keep the oil level constant, although these engines are becoming obsolete because as they age oil consumption becomes an increasing problem.

Detroit two strokes are the oil burning engines of the yestar year.

Start up an old 71 series Detroit and talk to me about diesels not smoking!:eek::D I was sitting at a dock behind an old Hatteras that had a pair of 12V71 TI's. Oh dear God they fogged me half way up the dock and killed all the bugs within 100ft!:D

Naturally I was only speaking of the good diesels (like MB and VW), not some Detroit POS. :)

AFAIK there is no particulate filter on the pre-2007 US models. Engine oil ash content should not affect smoke output, though it may affect emission equipment in the long run.

They have a catalytic converter which does reduce smoke but it won't eliminate it like a particulate filter can.

x 2 to the above comment. the head has been replaced already... no way should that happen on an '06 vintage machine. get a new one and a new warranty. save yourself heartache..

It sounds like the head was repaced because the dealer busted off a glowplug in it, not because it warped or something...

I have a 99 E-300 td From day it was new if I stomp on it I WILL leave a cloud of gray smoke in my wake. I mean if I floor it. I can accelerate as fast as I need to with out going full bore however and there will be no smoke. The smoke comes on when I feel the turbo kick in. Kind of of like a big round cloud..just enough to surround the car behind you if they are to fast on the horn at the light (G)

yes head replaced at 32k miles.. ridiculous. he should get a new machine and start over with a new warranty.
cut losses now.

My E300 turbo will dust folks out too when I hit the kick down button and down shift 1 or even 3 gears when merging on the freeway or forcing a tailgaiter to back off. Sure makes merging easier with a cloud behind you......3/4 to 7/8 throttle usually won't unless a lot of load is on the engine such as going uphill, etc.

I suspect you've got a bad injector.

I understand why the head was replaced, but what went wrong with the turbo? Was that at the same time as the head?

Head replacement was a fluke
 

People have asked questions about the previous repairs to this car.

From what the dealer told me the head was fine except for the fact that the glowplug (they are very skinny, delicate things) had broken off in it during removal. He checked all of the other plugs and they all came out without a problem. Unfortunately, despite trying everything he could think of, the broken part could not be removed without damaging the head. Consequently, new head.

The turbocharger is a different matter. The technician said that it sounded completely wrong to him once he got the engine back together and he knew it was ready to fail. So he replaced it.

The alternator seems to have been totally unrelated, and was something they noticed when taking it on a final test drive before returning the car to me.

All in all, the repairs took over 3 weeks to complete. They lent me a nice C-class to use, so that was not a problem, but it did make me concerned. I estimate it would have cost between $5-7k had I been paying. The night I picked up the car I drove straight to CarMax (the local one is a also a Toyota dealer) and nearly traded it in for a brand new Toyota Avalon. They would have paid me a couple thousand dollars in the transaction. But even the short drive to CarMax reminded me of what a pleasure it is to drive the Mercedes!

Anyway, I will probably know by the end of the day what is going on. If I end up making another trip to CarMax I will probably be driving something else when I leave. Sadly.

You should show him this video: http://www.youtube.com/watch?v=koghDoROFko

You need to think very carefully about selling this car. It is a natural instinct to want to dump your car after having gone through major repairs, but give it some time and look at it another way. With the smoke issue aside, the car is now probably in better shape than when it rolled off the factory floor and there's a good chance it will be trouble-free for many years to come. And the smoke could just be from low cetane or some other fuel quality issue. At worst it's a leaky injector and that's a relatively easy fix. You still haven't mentioned the air filter. Was it ever replaced?

MB needs to redesign the glow plugs to make them sturdier. I used to think this was just an issue with the OM606 engine, but apparently not.