Just curious if there's anything to look out for when checking out these vehicles beyond the normal inspection stuff.

How reliable is the airbag suspension system?

For example, early version of the M276 engine have timing chain tensioner issues... those kinds of unique things.

 

I had mine, same year for about 8 years now. I had to work on the air suspension a few times. There is a kit that replaces the whole system with regular springs and shocks, but although people love it and claim that it feels the same, I personally would like to keep mine original. Replace the a/c compressor due an oil leak above it. apparently it had been leaking or a long time, and messed something there. (had to go to the dealer for that one, around 2k that time). there is a couple of plastic plugs behind the heads that needed replacement. did it my self for less that 40 dollars. going back to the air suspension, I have done the replacement of the bags myself, and there are plenty of places you can find quality parts at affordable prices. at this point i'm about to replace both front control arms, and rear control arm bushings. they are busted. However, my vehicle is over 200k miles now. Engine wise, have not had an issue. still very powerful. as long as i keep injectors clean, good plugs, and the mass air sensor clean. overall? It is my backup "truck", those folding seats allow me to put big items in there, so in a nutshell, i'm probably keeping it for life. I just love it.

 

Make sure your car is not affected by the M273 balance shaft sprocket issue - google this and input your VIN and it’ll tell you.

Airmatic components will without fail need replacement at around 80-120k. Good news on this is that there are cheap and very good aftermarket alternatives to stock. Do not convert to metal springs.

water intrusion around the rear d-pillar and Cabin air filter box will fry sensitive electronics - don’t buy one that is wet inside

the valve body speed controller in. The transmission will get dirty and fail if the fluid hasn’t been replaced at 40-60k mile intervals

the above are the cash intensive problems

all the black window trim will peel and look bad

the last one is a nuisance only.

 

I believe all 2007's and most 2008's were affected by the sprocket issue. Go for a 2009 or later unless you can get one at a good enough price and swap the engine or do the repair yourself if it ever occurs.

 

no - some of 2007s only.

 

Correct. My 2007 has engine S/N ...104009 which (thank gawd) is in the range with the improved idler gear.

 

Mine is a 153918 and it suffers from the balance shaft gear issue.

 

Isn't that a different problem?

 

No.

 

Oh, right you are. Dunno why you got unlucky.

 

Balance shaft gear on the m272
m273 doesn’t have a balance shaft so it’s an idler gear.

Some we’re not properly heat treated from the supplier and wore out prematurely - that’s why cam timing goes off prematurely.

 

I really ought to learn to read, as momma said. I don't understand enough to know why these two problems are conflated.

Mercedes Medic has a modestly useful writeup on the problem:
http://www.mercedesmedic.com/check-m...y-vin-m272273/

 

Yes, timing chain idler gear in my M273. The problem is far more widespread than listed in the link. Mine, as stated above, is outside of the list but still suffers from the gear wear. I think the earlier ones were just more prone to fail early. I've got over 250k miles on my engine and other than the CEL light it runs perfectly. In time, it will fail.