Hello MBworld,

Don't mean to bug you guys, but I'm new to the Mercedes world and recently picked up a 2013 C300 4matic with 34K miles.

On cold starts I get this nasty knocking sound from the engine for around 3-5 seconds. It definitely sounds like something is trying to build up oil pressure during that time and being such a new car it shouldn't sound like that. As I was told these cars may have an issue with the cam adjusters and may be an updated version, but I don't see any recalls for this.

Does anyone know anything about this or experiencing this issue? I've searched everywhere and can't find anything on it. It can't be normal. And I understand these cars are direct injection and make more noise, but this just does not sound right.

Any feedback would be appreciated.

Thanks

 

Does it sound like a diesel engine for a few seconds? There are a couple threads going on that right now. I just had my timing chain tensioner go bad. My car had long crank time followed by the sound.

I have a different engine but check my audio clips in this thread, https://mbworld.org/forums/c-class-w...ml#post6783733. Get it to the service department as whatever it is probably isn't normal.

Welcome to the forum!

 

Yes it does sound like a diesel engine for about 3-5 seconds untill it builds up oil pressure. I don't have a long crank though.

I appreciate you sharing this information with me. After doing some research I do indeed have a similar issue as you.

Come to find out in Alldata there was a TSB for faulty timing chain tensioners. Basically Mercedes came out with an updated timing chain tensioner with an added relief valve to avoid this issue on startup. I'll be taking my car to Mercedes next week to hopefully get this fixed by factory warranty.

 

A 2013 with 34k miles should be under warranty, should it not?

 

I'm still perplexed about the timing chain tensioner failing on my far with 26,000 miles. Most mechanics seem to think it odd.

 

This issue has a documented fix. Chain tensioners and check valves. Search the forum for knocking or startup or something similar.

 

Any idea if the C250 and C300 used the same chain tensioners? Seems odd we've had a few posts on these the past week or two.

 

Yes according to one of my Mercedes techs they have to cover this issue. But knowing the dealership they will say it's normal. Good thing I have a TSB printed out on this repair. I'll be taking my car their soon once I get my tag.

 

Yes it is very odd. I work at an automotive shop and my techs were shocked when they heard this nasty sound on such a new car. It's not normal, you should take your car to Mercedes and get this repaired.

 

They shouldn't as yours is a 4-clinder.

 

Did the timing tensioner resolve your issue? I plan on going to the dealer soon because I'm having the same issue. Any idea where you can get the TSB so I can bring one with me?

 

I have same rattle but only at worm starts after park car and restart for an hour rattle last few seconds no engine light is on