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Hi all. Recent M4 owner. I know this has been discussed endlessly by BMW owners but I***8217;m suffering from an engine knock that just doesn***8217;t seem right. Car is a 2014 M4 6MT. 50k miles, full dealer history. Noticed when purchasing (private seller) the faint tapping sound and put it down to noisey valve train/vanos and the car drove excellent so I wasn***8217;t too concerned. As I***8217;ve owned it over the last 10 weeks I***8217;ve noticed it***8217;s louder on occasions.
First point: from cold the engine purrs and there***8217;s no abnormal noise, just usual lifter tick and injector noise.
2nd: the noise is only apparent when the engine reaches normal operating temp.
3rd: I assume BMW used 5w-30 at last scheduled service. I thought I***8217;d try 0w-30 plus I like to put fresh oil in when I buy a car. This made no difference either way and noise still appears when warm.
4th: the car had an akrapovic system fitted before I bought it, ive just had a litchfield stage 2 tune and they didn***8217;t mention any noise issues but I***8217;m not convinced they would.
Lastly: I***8217;ve now changed the oil to 0w-40 to see if a slightly heavier oil makes an impact, the second video is after the oil change. It***8217;s definitely quieter, but still there. I tried the lifter bleed procedure and I couldn***8217;t see any improvement. If the noise is inherent of BMW valve train I***8217;m not concerned, but it***8217;s driving me crazy trying to figure out if it***8217;s a rod/bearing issue, a loose plug, manifold gasket issue. I need to diagnose properly before taking to a dealer as it***8217;s no longer under warranty and they***8217;ll spend hours if I can***8217;t point them in the right direction.
Any help greatly appreciated!
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