I have one, and like it thus far.
Every opinion I've read states that the engine's destined to be a boat anchor after 400k on the clock. Mine has 430k, and shows no signs of dying anytime soon. There are a few here who have responded with 500 and 600k, and they're still running. A friend of ours met up with someone recently with 930k on the clock.
Owner's manual says maintain every 20k; I do mine every 12. I am the 3rd owner of my truck, and know the previous 2 were just as picky.
There are no sleeves in the cylinders, and Mercedes/Detroit/Freightliner has told me no rebuild. However, I have been told by a Mercedes shop that a Cat dealer in Michigan has done a few. I called and asked for a price, and have never gotten a call back.
I have been quoted from $16k to $25k, including labor, to replace. I WILL replace mine, when the time comes. There's nothing wrong with the truck.
The tradeoffs, IMHO: Motor's not made for pulling heavy weight. I've done a few 13,000# loads, and she labored, but performed. Not something I'd do regularly, or really have to. Definitely not made for that. Unknown if rebuildable, or has to be replaced. That being said, I get 11+ mpg. I'm limited to 65 mph. While I haven't crunched numbers, I believe the fuel economy more than pays for a new engine over it's life span.
Things I don't like:
PM's are costly. The centrifugal oil filter alone is $45-50. Regular PM's at Speedco, without replacing the fuel/water seperator element are $224. Class 8 trucks are less. I'm switching over to a bypass system when I go home.
Injector lines-The early ones are known to vibrate loose, spraying fuel everywhere. Ask me how I know. There is a repair "kit" available at Freightliner, with vibration dampers, and even covered under a recall, if your serial number fits. Mine didn't....how curious. $460.
EGR coolers- early ones fraught with problems, and were almost guaranteed to go every 80k miles. My last one went over 150. I'm told they are better engineered now, and have even heard there is a check valve fix that completely eliminates the problem. Part is just under a grand, half a day's labor on top.
They're nutless, as mentioned above. However, we rarely haul anything over 6-7000# weight, so are okay in my book.
I think they're great in an entry-level truck, but I would not own them as part of a fleet, or spec a truck with one, unless it was the higher horsepower version. Mine's been good to me, but I have been good to it. I pamper it.
DaveKC has some insight on them, I believe.
Hope this helps.
AJ
