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Took my C250 into an independent mechanic to diagnose a P034062 code.
After removing the intake camshaft magnet to inspect the camshaft adjuster, they determined that
the "securing pin for the camshaft adjuster gear is broken, and a new camshaft adjuster is needed".
I tor the front of the engine down, removing the upper timing cover. I honestly don't know what the mechanic is talking about.
I can send pics and or video of me manually cranking the engine, timing marks line up, chain seems tight, and i can't see anything obviously wrong with the intake camshaft adjuster.
There is no securing pin. The intake camshaft adjusters break internally, causing check engine light on, extended cranking and rattle noise on start up.
Since I was as far in as I was I went ahead and disassembled the intake camshaft adjuster. It looked fine to me, pics attached. The only thing I see is some wear on the back plate of the adjuster where the internal pin locks in, and some rounding of the end of said pin.
Since I am already in, I went ahead and ordered the following:
timing chain adjuster
timing chain
control valve that holds the camshaft adjuster on (I broken the existing removing it)
intake and exhaust camshaft adjusters
I question whether or not I need to change the timing chain, it wasn't really loose, and the timing was spot on when I checked the marks. Since the part number has changed for both camshaft adjusters, I also am assuming the newer versions are better.
What are everyone's thoughts on the need to change the chain and exhaust adjuster too?
I am right there with you Chris. I have replaced the 2 adjusters, but didnt order a chain because mine looked fine. I will upload some pics here tonight when I get home. My problem now is this. I get the hormonic balancer at top dead center and the 2 adjusters line up. But of turn the engine manually 1 full turn, they arent lined up again.
Which tool kit did you use for the timing chain? There are lots of kits available for securing the camshafts but no one makes a timing chain riveting kit specially for the M271 Evo.
2013 C250 SPORT, 2014 WRX STI SEDAN, 2017 E300 4MATIC
Originally Posted by The Critic
Chris, any update?
Which tool kit did you use for the timing chain? There are lots of kits available for securing the camshafts but no one makes a timing chain riveting kit specially for the M271 Evo.
I just did this on my car same engine. To lock the cams I bought a $60 locking kit from eBay. The locking jig did not fit very well so I modified it a little using electrical tape. To rivet the chain used a $15 chain breaker tool from Harbor Freight.
I did not end up changing my timing chain, although I did buy a new chain and breaker off Amazon.
I did replace both camshaft adjusters, although I am not sure it was necessary for the exhaust, but since I was in there ;-)
Knowing what I know now, I probably wouldn't have replaced the timing chain tensioner, it is too easy to reset, and I had to reset the new one once anyway.
After getting it all back together it runs perfectly now.
Getting the adjusters off was a bear, and ultimately had to buy an electric impact wrench which made quick work of it. I broke the solenoid trying to muscle it off first. Save yourself the headache and potential cost and get/buy and impact wrench.
I don't plan on doing the job again, so if anyone is thinking of taking it on, I will happily part with the engine specific tools and the new chain I purchased at a 50% discount. Let me know and I'll calculate the cost.
azblk - thanks. I purchased the kit from Baum Tools for $350, hopefully it will be more accurate. The plan is to resell the kit once I am done with it. Do you have any pictures of the process from “drawing the chain” thru? I am trying to visualize how the process is done. The concept is a bit baffling to me. The MB Service Instructions are somewhat cryptic, at least compared to the Toyota/Honda factory instructions that I am personally familiar with.
Chris - thanks for the update and I am glad to hear you were successful. The vehicle I am working on belongs to a friend and he is selling it once the repairs are complete. So unless it is absolutely necessary, I only plan to replace the intake adjuster, VCG and seals, coolant pipe o-ring, upper timing cover o-ring, tensioner, tensioner plug and thermostat. If this was my personal car or if he was keeping it, I would certainly take you up on the offer.
2013 C250 SPORT, 2014 WRX STI SEDAN, 2017 E300 4MATIC
Originally Posted by The Critic
azblk - thanks. I purchased the kit from Baum Tools for $350, hopefully it will be more accurate. The plan is to resell the kit once I am done with it. Do you have any pictures of the process from “drawing the chain” thru? I am trying to visualize how the process is done. The concept is a bit baffling to me. The MB Service Instructions are somewhat cryptic, at least compared to the Toyota/Honda factory instructions that I am personally familiar with.
I tied the new chain to the old chain and pulled it through by rotating the crank pulley. I cant find a good picture of that but basically threaded copper wire through the last link on the old chain and attached it to the first link on the new chain.
In my experience you can usually open the adjusters up flip the pin inside upsidedown to the edge that isnt worn down/chamfered and get a few thousand more kms out of it. you can go one step further and bore out the plate a bit so the indentation is deeper which will hold the pin more securely.
Hi
Looking for a little help please. I see in your photo that your Crankshaft pulley dial is showing a half degree off/before TDC. I was advised by a mechanic that I need a new timing chain kit but when I took off the valve cover I found the same as in your photo - out by only half a degree before TDC - with my adjusters lined up properly. Is your photo before or after you fitted a new chain? The Mercedes Factory WIS is a bit ambiguous as to whether the timing indicator needs to be exactly on TDC on the crankshaft pulley dial or can be up to 2 degrees out "+ or -". My chain is really tight and and the sprocket teeth look good, so I imagine that a half degree out at TDC is indicative of minimal wear and within tolerance. Or was everything exactly in line after you fitted new parts? Many thanks
Last edited by bellydancer; Mar 23, 2025 at 12:37 PM.
Reason: correction
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