2012 Mercedes-Benz C250 1.8L TGDI - P034062 - Cam Adjuster Repair

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Vehicle: 2012 Mercedes-Benz C250 Sport w/1.8L M271Evo Turbocharged Engine. Mileage: 86K This car belongs to a buddy of mine. He was experiencing long cranks (2-3 sec to start) and a check engine light (CEL). When the engine finally started, there was a loud clatter for several seconds. When scanned, the fault code was a P034062. Since my buddy was planning to sell the car, he had to fix the issue in order for the car to pass the CA Smog Inspection (CEL is an automatic fail); you cannot sell a car in CA that does not pass smog inspection unless it is being sold as a non-operational vehicle. After some initial testing and research, the issue was isolated to the intake camshaft adjuster (phaser). My scan tool was unable to perform the cam adjuster test so I sent the car to the dealer for diagnosis (1hr - $198). The dealership returned with the same diagnosis but recommended replacement of both cam adjusters (intake and exhaust). The dealer's estimate was $5600. After some additional research, replacing both adjusters is standard practice when addressing this issue. I took some pictures of the repair process below: After removing the air intake hose (a $216 hose w/sensors that crumbled when touched), drive belt, alternator, thermostat, p/s hard line and valve cover, we are left with this: [Linked Image] After setting the crankshaft to TDC and taking a closer look of the intake cam adjuster (the failed one), we can see that the mark on the camshaft (middle mark) no longer matches up with the reference arrow. The camshaft timing is noticeably advanced. Apparently, this indicative of a worn/failed camshaft adjuster. [Linked Image] At this point, I removed the one-time use timing chain tensioner and attempted to install the hold-down tool. Since the intake cam was obviously advanced, I tried to manually move it back to its correct spot and install the tool. This worked (barely) but I was still unable to install the tool on the exhaust cam. Let's take a closer look at the marks for the exhaust cam and exhaust cam adjuster: [Linked Image] From an initial look the exhaust cam adjuster appears OK. But as it turns out, the exhaust cam was slightly retarded. So even though the exhaust cam adjuster was not displaying any faults, there was some slight wear on this adjuster as well and perhaps this is why dealers often recommend replacing both adjusters at the same time. And both adjusters have gone thru multiple revisions. I sent these pictures to a few trusted contacts and all of them suggested replacing both adjusters. Now let's revisit the marks after the adjusters were installed, new tensioner installed (and extended), and after the engine was spun-around several times. Intake Camshaft Adjuster: [Linked Image] As you can see, the middle mark is now where it should be. Exhaust Camshaft Adjuster: [Linked Image] Not a huge difference compared to the "before" picture, but this was enough to allow the cam locking tool to just drop into place. Here is a picture of both new adjusters installed: [Linked Image] The at the 3 o'clock (exhaust) and 9 o'clock (intake) sprockets do not align perfectly. I have seen pictures of these marks aligning with a new chain. So, I think the chain in my engine has some wear. Since the tensioner was not fully extended and there were no cam/crank correlation codes, I skipped chain replacement at this time. Here is a picture of the engine after being fully reassembled, minus the engine cover: [Linked Image] List of parts used: [Linked Image] After bleeding the cooling system and the p/s system, an oil change was performed. Codes were cleared and the car was test driven. The fault codes did not return and the engine started up normally without any abnormal rattling sounds. I decided to keep the car for a few days to do an extended test drive. After 140 miles of perfect operation, while merging onto a highway, the car went into limp mode and displayed a severe lack of power at high RPM's. I made it back to the shop and found a P000277 and P061A22. After some research and testing, it appears that the high pressure fuel pump decided to fail. This is not an uncommon issue with these engines, either. I will make a separate thread for that repair. This car is currently for sale in case anyone is interested: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/5154182/fs-2012-mercedes-benz-c250-sport - The Critic
 
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Good read ! These cam phasers seem to impact a variety of Benz engines of that era all the way up to the V8/V12's.
 
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Ontario, Canada
Thanks for posting this, its always interesting to see a job well done. My first thought was that this level of parts quality, sounds more like a chinese knock off car than an MB... But I guess they all make the odd car with issues.
 
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Suburban Washington DC
Perfect example of why the values of these cars drop like a rock after the warranty expires. Not sure I'd list it for sale until you get it fixed. What do you tell someone when they want to come look at it now?
 
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missouri
Having had the cam phasers and high pressure fuel pump already is a good selling point. The used value should go up significantly. Rod
 
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missouri
Originally Posted by KGMtech
low miles for such an expensive repair!
This is all in my humble opinion. This so somewhat typical of a European car. They tend to use bio degradeable plastic, so plastic things crumbling is quite common. I wonder what is the condition of the wire harness, another frightfully expensive repair. They tend to over engineer (very reduced safety margin for wear and overly small parts) The days of the MB designed to last for 500K miles with minimum repairs is gone. You should see what my neighbor has gone thru on his MB. He s correct, they do drive very very nice. Until they strand you. Oh and if you hit one, you better have good insurance. Rod
 
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Atlanta,GA
Originally Posted by ragtoplvr
Originally Posted by KGMtech
low miles for such an expensive repair!
This is all in my humble opinion. This so somewhat typical of a European car. They tend to use bio degradeable plastic, so plastic things crumbling is quite common. I wonder what is the condition of the wire harness, another frightfully expensive repair. They tend to over engineer (very reduced safety margin for wear and overly small parts) The days of the MB designed to last for 500K miles with minimum repairs is gone. You should see what my neighbor has gone thru on his MB. He s correct, they do drive very very nice. Until they strand you. Oh and if you hit one, you better have good insurance. Rod
EU Directive for end-of life vehicles.
 
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Thread starter
Originally Posted by atikovi
Perfect example of why the values of these cars drop like a rock after the warranty expires. Not sure I'd list it for sale until you get it fixed. What do you tell someone when they want to come look at it now?
I'll be transparent.
Originally Posted by Sunnyinhollister
Good read. 86K miles, looks to be maintained, and needs over $2k in parts plus labor. They are nice cars but the pay to play price is too high for me.
The HPFP was another $450 so I think we have ~$2250 into it at this point.
 
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USA
Originally Posted by ragtoplvr
[quote=KGMtech] The days of the MB designed to last for 500K miles with minimum repairs is gone. You should see what my neighbor has gone thru on his MB. He s correct, they do drive very very nice. Until they strand you. Oh and if you hit one, you better have good insurance. Rod
Exactly, that old reputation is finally dead in the minds of most consumers today. That's why increasingly these former iconic car makers are in serious trouble. Their entire reason to exist is virtually gone.[/quote]
 
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Was there any indication that the oil had not been changed regularly during the cars life prior to this? Another sign that MB quality is not what it used to be.
 
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Originally Posted by PimTac
Was there any indication that the oil had not been changed regularly during the cars life prior to this? Another sign that MB quality is not what it used to be.
The top of the engine looks okay but does have some light varnish. It was a rental for the first part of its life, then after that it was dealer-serviced at the correct intervals before the current owner purchased it.
 
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Albany, NY
86K wow I really appreciate my Lexus now. I never heard of a phaser/timing failure on the forum. That job is at least 4k at an indy. Now a HPFP frown. What was the mode of failure? Sometimes they die because of extended OCIs and the cam wearing down. Maybe the first problem was due to that too.
 
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