2009 E350 Tapping Noise Only When Starting Engine
Thread Starter
Member
Joined: Jan 2004
Posts: 75
Likes: 6
From: Virginia
17 E300, 17 C300, 14 C250
2009 E350 Tapping Noise Only When Starting Engine
Slight tapping noise when I start the engine on my '09 E350 with 49K miles. It lasts only about a second and only does it if the car has been sitting for a few hours. After 2 seconds car sounds perfect and if I restart the car no noise unless a couple of hours go by.
Sounds like only one valve is noisy - car has had better than scheduled maintenance with MB recommended oil & filters since day one. Car has never been abused and uses zero oil between oil changes. Any ideas?
Sounds like only one valve is noisy - car has had better than scheduled maintenance with MB recommended oil & filters since day one. Car has never been abused and uses zero oil between oil changes. Any ideas?
Senior Member
Joined: Aug 2011
Posts: 356
Likes: 19
From: RI
2017 S550 4matic
if it isn't valvetrain noise, your injectors may be sticky. This can make some noise too. Every car I've had that same noise on (higher mileage typically) I run a bottle of lucas fuel system cleaner through and quiets them right down.
Senior Member
Joined: Aug 2011
Posts: 356
Likes: 19
From: RI
2017 S550 4matic
dunno where your post went, but i saw it in my email. To clarify, i'm not talking about removing injectors and 'flushing' them with some kind of cleaner, i'm talking about your typical fuel system treatment added to the tank before you fill up. Just once in a while of course, but I prefer to use the Lucas fuel system cleaner concentrate rather than the Techron. For one, it's cheaper, and one bottle treats up to 20gal so I feel it gives enough cleaner:gas ratio for my usual ~15gal fillup. Gets the water out of the lines, helps clean up some of the carbon in the combustion chamber/valves and has lubricative properties to help keep moving parts in the fuel system moving smoothly.
MBWorld Fanatic!
Joined: Aug 2011
Posts: 3,184
Likes: 16
From: Highlands Ranch, Colorado
2014 BMW M235i
dunno where your post went, but i saw it in my email. To clarify, i'm not talking about removing injectors and 'flushing' them with some kind of cleaner, i'm talking about your typical fuel system treatment added to the tank before you fill up. Just once in a while of course, but I prefer to use the Lucas fuel system cleaner concentrate rather than the Techron. For one, it's cheaper, and one bottle treats up to 20gal so I feel it gives enough cleaner:gas ratio for my usual ~15gal fillup. Gets the water out of the lines, helps clean up some of the carbon in the combustion chamber/valves and has lubricative properties to help keep moving parts in the fuel system moving smoothly.
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Junior Member
Joined: Jan 2002
Posts: 19
Likes: 2
From: Cincinnati, OH
07 C350 Sport
Does it go away after reving up a little?
Does it happen all the time? Might be the Gas Purge valve , located in the front of the engine compartment. Drivers side black plastic looking device.
You might take it to your dealer who will have the noise technician (with Stethescope) look at it.
Mike M
You might take it to your dealer who will have the noise technician (with Stethescope) look at it.
Mike M
