Advice on Work Done on 2009 C300
Took my 2009 C300 to an independent autoshop for a diagnosis and was quoted almost $300 for a "BG Engine Performance Service (BG MOA/EPR/44K)" service and $500 for a "BG Platinum Fuel / Air Induction Service" service. Did some research and keep seeing the latter is a BS service these shops charge to get more money out of the customer. Not sure about the first service though. I've attached pictures of both services for more detail. Am I right to decline the 2nd service and for the 1st service, is it necessary? I have about 95,000 miles on the vehicle, no accidents. The only repairs I had on the car were: all tires replaced, serpentine belt replaced, front right wheel bearing and axle replaced, front brakes replaced, engine and cabin air filters replaced, and motor blower replaced. Last oil change was Nov 2025, I've driven nearly 3000 miles since.
Thanks in advance!




I am always doing some type of maintenance on it to keep it in good running condition. I follow the maintenance schedule in the maintenance booklet that came with the Operators manual in the glove box. Yearly oil and oil filter change, replace air filters every 4yrs though I will inspect and clean them yearly and replace if really dirty, replace brake fluid every 2yrs, transmission fluid and filter change per mileage on the car, coolant replaced per mileage on the car etc. Most of the time im just inspecting and cleaning things.
I would not pay for those two services above. I use Mobil 1 0W40 and the old oil always looks good, I cut the old oil filters open and never notice anything abnormal in them.
For fuel treatment I have been using Techron in my vehicles for years and was happy to see it being recommended by MB. I will add it to the gas tank when im filling up once or twice a year. 1oz per gallon of gas. On an empty tank pour in 12oz Techron then get 12 gallons of gas. I will add it when I dont plan on taking a long trip so I dont burn thru the 12 gallons of gas in one day. I buy the 32oz value size at my local Napa auto parts store when they have it on sale for $13.
I like to verify the information for myself so I will post where I get my info from about no additives in the oil and with using Techron in the gas tank.
Operators Manual:
Operators manual for earlier models.
MB Maintenance procedures manual.
I'd also question their stated ability to be able to migrate the molecules of fuel borne cleaners to impact the inlet valves on GDI engines. Even though yours is PFI I'd still ask that question. Have your pen ready as the answer will be an epic work of fiction that could include quantum entanglement and/or microscopic worm holes and the 4th dimension.
It's practices like this that give the trade a bad name.




My M272 engine has over 160,000 miles on it now. I replace the oil and oil filter once a year with Mobil 1 0W40. I just recently did it and cut the old filter open and there was nothing of concern in it, just a normal looking used filter.
When I got the car a few years ago I had noticed oil stains at various areas on the engine. No leaks, no fresh oil, just oily gunk. I cleaned up the engine best I could with degreaser, a tooth brush and rags. Removed the air filter housing, maf, and the elbow below it. There was some oily residue which is probably from the crank case breathers. Wiped the throttle body and put everything back together.
I cant see the above products cleaning the things I cleaned by taking things apart and wiping them clean.
Heres what my throttle body looked like:
Looks like the oil is coming from the two breather covers on both cylinder heads:





