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Kevin, Master tech
Category: Mercedes
Satisfied Customers: 2033
Experience:  Diagnostic technician
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My 2012 ML 350 has a loud annoying noise upon start for

Customer Question

my 2012 ML 350 has a loud annoying noise upon start for 3/4/5 seconds. The explanations I have seen are"its just something they doesn't affect engine life"to"timing chain" issues.Whats the truth? Any how can I get that fixed
Submitted: 10 months ago.
Category: Mercedes
Expert:  Matt replied 10 months ago.


can you describe the noise a little ? is its a squeal or a rattle , whereabouts on the engine is it coming from? does it rise and fall with engine speed?

Customer: replied 10 months ago.
It's more of a rattle for a few seconds ..... It goes away in a couple seconds.
Expert:  Matt replied 10 months ago.


Ok if its a high light noted rattle that seems to originate from the front of the engine and also gets louder if you remove the filler cap then yes its likely to be the timing chain

these engines have a hydraulic tensioner element that can be a little slow to 'pump' up from cold and so you can get a brief rattle from cold

it can also be alleviated with a change of oil grade

as depending on how hot your climate is then this will effect the correct choice of oil grade

if its cold ( sub 10deg C) then the engine should be running the thinnest recommended grade of 5w30

if you're currently on one of the thicker grades 5W40 or 15W40 then I'd suggest to try come back a grade

if you can tell me what you're running at present I can make a specific recommendation

Customer: replied 10 months ago.
Expert:  Kevin replied 10 months ago.

Hi im kevin do you still need assistance ?