General Rattle noise after cool morning start

LAdrummer said:

Does anybody know what this rattling sound is and should I be concerned? Thanks in advance.

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rovie said:

Can you explain this in more detail? In the engine compartment, under the vehicle, inside?

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LAdrummer said:

Sorry, I thought my video was uploaded. here it is.

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rovie said:

To me it sounds like vibration of an add-on part, loose sheet metal, etc. From my point of view, this is not coming from the engine. Take the plastic cover off and touch various components with your hand while the engine is running.
By the way, the video is now also displayed in your first message. For whatever reason, this was delayed.

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LAdrummer said:

Thank you Rovie. I’ll take the cover off and investigate as you recommended. I’m pretty sure it’s internal (engine tapping).

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rovie said:

Does the noise disappear when the engine is warm?

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C-Mack said:

If it sounds the loudest in the back left corner of the engine compartment, as you are standing in front of the vehicle, that is where the High Pressure Fuel Pump is located for the direct injection system. The pump sits on top of the valve cover on the petrol powered models and operates at well over 300 bar in pressure and can be quite noisy especially after engine start and during cold idle. It should quiet down as the vehicle warms up but you’ll always hear some amount of clicking/tapping coming from it and the associated rigid fuel lines routed across the top of the engine.

Most direct injection engines have similar noises and when I first got my Grenny it really stood out to me. I have other direct injection vehicles with similar fuel system sounds but by far the B58, as it is installed in the Grenny, is a bit louder than most to my ear. It’s a totally normal sound and a characteristic of the B58 engine family and you can even check BMW forums and on Youtube and you’ll see folks equally puzzled and worried about the noise thinking something is catastrophically wrong with their engine but it’s fine.

Also, with no extra sound insulation located around the engine compartment especially down the sides and underneath where the bottom half of the engine is fully exposed, extra noises will more easily be transmitted but honestly all is fine.

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LAdrummer said:

Thank you C-Mack! I am very grateful you took the time to write this explanation. Much much appreciated. You’ve put my mind at ease.
All the best,
Michael

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