Benz44

Hi all,

I am considering a move to MB diesel but have one major hurdle: One of my cars is a 2010 335d which at 58,000 miles had to have the engine taken apart to remove carbon build-up (using walnut shell blasting). Other readings I have found indicate that diesels all face the 'carbon dilemma' more frequently than that of a gasoline engine. Do any of you have 60,000+ miles of experience with a Bluetec engine? Have you experienced any carbon build-up problems (failed injectors, Check Engine light, diminished power...)?

Thanks,
Rob
E63, 335d, C250

Micah / AF1 Rac

Mine isn't stock but...without egr and case ventilation going through the intake side stuff stays a LOT cleaner. The same issue is becoming very common in direct injection gasoline motors too for many of the same reasons. 145k miles on stock injectors with fingers crossed as of tonight.

Micah / AF1 Rac

Question for the technical types on this forum. Part of my job is cleaning and testing gasoline and propane injectors. It's a very simple cleaning process, ultrasonic cleaning tank with injectors immersed in the solution as the machine hums away, while immersed they are continually pulsed by the expensive part of the machine? I've not yet had to mess with any diesel injectors and assume they require a much higher drive current due to MUCH higher fuel rail pressures? Anyone know if this is even feasible with modern diesel electronic injectors? If so it would save a lot of people a lot of money it sounds like?

boardboy330

OP, I too have an I6 like Micah. Mine as well is modified (no EGR) and I have 155K miles on it. I live just outside Washington DC and will be driving to Philly today. It's about 3.5 hours one way and about 200 miles. I expect to get 40mpg the entire time. As for reliability - I wouldn't worry about it myself if you got a 2005 CDI or 2008-9 Bluetec. I don't have experience with the Bluetec, but you don't want the first year in any vehicle.

@Micah, yes you can clean diesel injectors the same way, but you need to keep the electronics out of the solution as per normal. There are companies that can clean the injectors for you, but of course, as soon as they hear it's for Mercedes (regardless that most other vehicles use Bosch injectors) the price goes up.

Micah / AF1 Rac

I'll have to read up on the cleaning process and talk to my efi parts vendor for the cleaning stuff. I have stands for the injectors that go into the tank, technically you are supposed to do gasoline ones the same way, I'm getting better results from full immersion so I do them that way? I like doing as much as I can myself, it keeps the little diesel fetish interesting b

Benz44

OP here. Interesting comments from some of you relating to the (lack of) EGR valve as I am certain this (having one) was the main cause of the early carbon build-up in my 335d. BMW issued a recall in Spring of 2012 for this valve. I had around 30,000 miles on the car at that time. Luckily, I was able to dodge a $12,000 repair bill a year later when they had to replace all 6 injectors and blast-clean my engine to remove the carbon buildup. It was too late for me with the BMW but one thing I know I will do: Buy the extended coverage if I do get another diesel (regardless of manufacturer). There are too many extra diesel emissions related components on modern diesels.

Micah / AF1 Rac

EGR is perhaps the most or second most pointless one of the all. My coworker has one of the newer twin turbo Ford V8's, when that thing is doing its DPF regen cycle you can literally light paper on fire from the tailpipe, really helps the fuel economy too lol.

isstay

35d engine is prone to carbon build up because of it's aggressive tune and tighter US emissions. MB don't have this problem, but if you get V6 diesel you may experience problems with intake swirl flaps (motor gets soaked in oil from the turbo and stops) plus 7G-tronic is crappy and expensive to maintain plus lost some of the functions available on 5 speed, thus why if you are after reliable diesel and you don't mind the car age look for 05-06 CDI. You will get I6 like BMW but no intake problems (I took mine off to clean the flaps just to find out that there is almost "0" carbon build up on them - less than 1mm total for both sides at 100000 miles and you can remove them if you wish), EGR is easy to disable (they all have EGR), has old fashion solenoid injectors that are easy to rebuild, turbo is bigger (more potential) trany is owner serviceable. All engine parts are metal so no cracking plastic pieces (except two idler pulleys and tensioner pulley) and extra cost. Only emission device is a O2 sensor before the cat and car runs just fine if you replace the cat with pipe, on other side V6 Bluetec has DPF, later ones AdBlue and all kinds of emission crap. But at the end this is only my opinion .