I'm looking to buy a 2010-2011 model C300. The vehicle would likely have 90K to 100K mileage.
What mechanical issues should I lookout for with this model of this age? What major maintenance or correction should have been done by this age, so I don't end up spending a lot doing it myself?
Thanks for your help.

 

Guessing you already bought this car as you posted like 6 days ago.

Known failure points and problems:

Electronic Steering Lock and Electronic Ignition System - Nicknamed "Mercedes Sudden Death" as there is no warning or indication of this part failure. Can be a $1000-2000 repair out of warranty and you have to find a shop that is approved to order Mercedes "Theft Relevant Parts" to perform the repair.

Taillight housing melting - Under recall so its free, if not done make sure you get this handled at MB dealer. My taillights never went dark but failure mode on my '09 was incessant errors on the dash saying everything out back was burnt out. Ignored this will cause outages and dim taillights not working properly.

Rod knock - M272 engines (3.0 and 3.5) are known for a hot start and in some cases a cold start knock that lasts 3-5 seconds. Reading online it does not appear to adversely affect engine reliability and is just an annoyance and an embarrassment if people are around to hear your "best or nothing" car knocking away on start. Seems to be rod bearings were not sized properly from the factory and new rod bearings will fix the issue.

Maintenance items:

For a car this age budget to start replacing all the rubber parts. My '09 will be 10 years old in April and all the rubber parts are starting to let go. I need new engine and trans mounts, my valve cover gaskets are leaking, suspension bushings have been noted as in poor condition and my serpentine belt is squeaking. Engine and trans mounts quotes I got from dealership are in the $1500 range, have not gotten a quote from my independent but guessing $1000 minimum.

Other than that these are solid cars if you stay on top of the maintenance. They have a huge oil sump of 7-8 quarts so if the one you are looking at went a little past the 1 year/10k oil change mark I wouldn't be too terribly concerned. Trans make sure the fluid has been regularly changed (every 40k IIRC) as the 7G can be a bit touchy if ignored. 4Matic models have some known transfer case or power take off issues, mine is RWD so not too well versed on the 4Matic failures.

Happy motoring and enjoy your new C300!

 

Thanks pezzey. Not late at all. Exactly the sort of input I was looking for.

 

Also in addition to peezy669's common problems, you will also have to check to see if the passenger seat is on the tracks. This happened with both my 08 C350 and my family member's 09 C300 4matic. No one is overweight if your wondering LOL. its just a weird problem that you will get after a few years. Unless your lucky