2006 E350 engine noises
 

Hello all this is my first post in the gasoline section of Peach parts. I now have, or have had for about three years an 06 E350 with about 90K miles on it. Been driving MB diesels for years and been in that forum. We bought it as a CPO from the MB dealer with around 49K miles. It has had awhat was a slight knock, sounds like a main brg, at start up usually after sitting for at least 20 minutes. Now it has progressed to doing it at cold start up from time to time. I have an appt at MB Monday, I just wanted to hear from the gas side of the forum if there has been any history of this in the W211 series with the 3.5L V6? Thanks for any responses.

Have you been running synthetic engine oil like Mobil 1? If you have what kind of oil change interval have you been following? I am of the opinion that these are pretty robust engines.

Other than the "soft" balance shaft gears, they are a good engine.

Sure it's not just a valve tappet that bleeds down while the engine sits? I'm not as familiar with this engine, but every m112 I've ever heard has tappet noise like crazy after sitting overnight. It's really no big deal.

The other thought - again based on m112 experience - is carbon build up from too much gentle city driving. A good italian tuneup is the solution for this particular problem.

I would be very interested in hearing what your dealer has to say about the noise you are experiencing, as my wife's E350 wagon makes the same noise. I notice it more on cold starts and occasionally when starting the car after it has been driven and then shut down for more than 30 minutes.

The service advisor at the MB place here said not to worry about it, but it is not a pleasant sound, even though it doesn't last long.

There is a post or two on BenzWorld about this, but no one has reported back with a resolution to the issue, except one reply which states that replacing the "air pump" made the sound go away????

Good luck.

It's not common, but it's not unheard of either. After shutting off a hot engine (M272), and re-starting it a short time later, you hear a loud "DUNK....DUNK....DUNK...." for a few seconds. Is this your noise?

The fix is pretty straight-forward. Remove engine and dis-assemble bottom end. Inspect markings on crank-case, indicating what size bearing shells the upper side requires. Once this is determined, replace OE uppers with one size smaller bearing shells. Let us know what the dealer says. :)

I'm sure they will be thrilled to hear it:).

Actually you discribed it pretty close! well it goes to the dealer Monday, I service it or have it service according to MB intervals and use Mobile One. In fact the last couple services have been at the dealer. it sounds a little deep in the engine to be tappet, although I could not completly rule it out. With Warranty left i will not be pulling any engines.

Seems the dealer thinks it is a tapper bleeding down we will see.

Keith, I presume you use Mobil 1 0W40 in your 2006 E350. If not, switch to that weight Mobil 1 and see if the tapping sound disappears.

What are they gonna' do?

Okay, Keith, you have me on the edge of my seat....

What was the final verdict? Or did your dealer just tell you to ignore it like mine did. :D