Knocking/clacking noise on 12 ML 350 during cold start
if so, that the new direct injection...get more power and more efficiency, but it runs under super high pressure (similar to a diesel), so when the engine is cold, the noise is more pronounced. nothing to worry about.
this high pressurization is what allows the engine to be so fuel efficient, while at the same time be more powerful than the outgoing engine (piezo fuel injectors).
two things are to blame here: 1) government regulation for fuel efficiency and 2) consumer demand for more efficient and more powerful engines.
this is not manufacturer specific....all di engines will have a similar if not identical problem at startup.
hopefully you will rest easy now!
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In the grand scheme, this sort of problem is pretty rare, so they should be happy to go way out of their way to satisfy the customer.
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GM engines are notorious for this, but of course, GM says it is "normal." But over time, piston slap can scuff the cylinder wall and lead to increased wear.
Last edited by Shrdlu; Aug 3, 2012 at 03:55 PM.
Just saying.
If engine is replaced:
1. Vehicle will depreciate.
2. Engine id number wont match with vin.
3. Have to disclose if i decide to sell vehicle later on.
4. MB hasnt located problem so it maybe sometging else.
5. How many times have you had to replace engine on new vehicle with only 800 miles.
6. This vehicle is a lemon!
Appreciate any input..
They won't give u a new ML be glad they want to replace the engine.















