[IoannisAr]

Hello all,
I have my bmw for almost a year now, its an e90 320i with the n43b20a engine and about 189km on the clock.
I recently replaced all the valves from the engine head, resurfaced it etc.
After a long trip of about 300km when i finally stopped i heard a weird noise coming from the engine (i know the sound of the injectors and this sound was twice as strong).
The strange thing is that i can only hear this sound when the car is in idle. From the moment i place my foot on the gas the sound is gone (when i press the clutch the sound is the same and it is not changing).
Also the sound is not permanent, sometimes it is very loud, other times not so much and sometimes there is no sound at all.
First thing i did was to check the oil but it was in good level, the valves cant be because i just replaced them as i said.
Then i thought about the timing chain but i had it changed as well before 1000km.
There is no engine light on, the engine works perfectly normal, no loss of power or anything.
If anyone have an idea or had a similar problem please help

[geek]

You shouldn't discount the valves because you just replaced them. In fact, if a new noise or problem follows recent work, in general it's a pretty good bet that work wasn't done right.

The classic E90 "noise only at idle" is the idler pulley. When mine went bad, the noise would begin only after the engine had been running for few minutes, then it was a LOUD rattle. Went away at higher-than-idle RPM.