UWC300

Hello fellow w205 c300 owners,
I have a 2015 C300 RWD model and think I may have a wrist pin issue in the engine.
My engine came out of factory on 20.02.15.
My only concern is that the car is out of warranty and I did not purchase the extended warranty.
What should I do? Should I just bite the bullet and sell the car?
Engine has 52k miles on it.

Thanks in advance,

riotrhythm

My 2015 C300 had the wrist pin issue (and had it fixed) and my car did not sound like that at all. In fact, the videos of your engine unfortunately sound worse than my engine did.

My dealer estimated that the repair would've cost about $12,000 without my warranty.

I would at least have someone look at it to see if it is the wrist pin issue.

gfmohn

I had my wrist pin issue fixed in 11-15. The repair invoice was over $11,000 (zeroed out, of course, under warranty). This was in the Boston area.

Sam Manuel

My car is coming to 135k miles and I think I might have the issue too cause it makes all sorts of noises especially when the engine is cold.

what will eventually happen if it’s not fixed ?

ItalianJoe1

The wristpin noise will not be any worse than a noise on startup, mainly on engine decel, that fades out when it warms up, and should cause no further issues.

Serious knocking noises make me suspect a loss of oil pressure or timing drive issues, but in my time at Benz that was uncommon as they were still fairly new.

I will note, the M274 does NOT set a warning light for a complete loss of oil pressure. It will continue to run with <5psi of oil pressure, set camshaft timing faults and sound like a sewing machine, but no oil pressure warning. Have seen that happen before.

ItalianJoe1

Your noise sounds like an accessory drive issue, have you tried removing the belt and running the engine to see if it continues? That is one of the first test steps in confirming the piston noise.

I'd be willing to bet you have an alternator coming apart or a pulley on it failing. Or possibly an idler pulley bearing. That chirp type sound is more consistent with that type of failure.

UWC300

Thank you so much for your input on this matter. I have not tried to remove the timing belt yet, but now I am more concerned about alternator failing or a pulley being shot out of my bonnet while driving.
Since I read about the Spark plug change interval being somewhere around 46k mile for W205, I have just gotten an estimate for a spark plug change at a local German garage for about $215 (OEM parts, one hour labor); which I think it's decent price.
I will make sure to ask them to check if any accessory drive components is failing or not up to spec.

Regarding to Wristpin issue, the only issue is the noise when engine is cold? It won't scored up the cylinder wall or break the cylinder head? If that's the case, I will continue to drive it happily as it pulls great when engine is properly warmed up. I do make sure to put 92 octane gas every time.
Although I do have another issue with the front side (R&L) suspensions making squeaky noise when pressure is applied (getting in and out of car, going over bumps at low speed). I ordered a can of lithium grease to spray the rubber bushings and joints to see if that will fix it.
Is there people out there who is having similar sound issues with their suspensions (or sidearm bushing)?

benzdude

You can run the engine without a belt? Wow, I did not know that.

Why not take the car to the experts at MB?