Knocking noise - bmw 118i 2020

[Edwardpoole]

Anyone help? Knocking noise from my engine bay when I start up, sounds like a tractor… when I accelerate the knocking noise goes quicker.

Cheers guya

[Gassmi]

Main suspect:Timing chain guides. Common on these B38 engines. That tractor rattle at startup is the chain slapping because the guides are breaking up.

Why it speeds up: Revs go up, chain slaps faster. Classic chain symptom.

Do not drive it. If it jumps time, valves hit pistons = new engine time.

Fix: Needs a new timing chain kit (chain, guides, tensioner). Get a BMW specialist to do it - needs locking tools. Also check your oil level, low oil makes it worse, but the guides are already gone.