Hi scotty, I have a Bmw e82 125i 2009 model N52 engine naturally aspirated. The car starts fine, however when the engine is warm, it makes higher pitch noise. When the noise start, the rev count goes up and down and the engine misfire.
I changed pcv but the noise still pitches when the engine is warm. I don't know if I should change the whole valve cover tappet or there may be something else.
Thank you.
What is a valve cover tappet?? I thought all BMW engines started screaming just before they exploded. Seriously, I'd check the alternator pulley in this case since it seems to be affecting your idle and ignition.
I seriously doubt if its the alternator pulley, because if I open the oil cap while engine is running, the noise stops immediately. And when i close the cap, it will wait until enough compression is built then start the noise. Its more like the air is not circulating properly as it should.
Failing PCV valve. BMW calls it something else. Hope this helps -
https://www.carid.com/2009-bmw-1-series-oem-emission-control-parts/
I had a similar problem with my N52 engine. It was like a high pitched noise. But if I stopped and restarted the engine, it would go away. I never really bothered to fix it.
With that said? When I changed the valve cover itself, the problem seemed ti have gone away. There is some sort of valve that is built into the valve cover. If you remove the beauty cover, and you are looking at the engine from the front, it is located at the top back left.
Yes, i think the issue is that valve. Its got some orange rubber and the spring that helps it to and close when idling and accelerating. And this issue makes the car to burn a lot of oil, and the smokes if you drive for a long time. And so to avoid excessive burning of oil i always have to drive a bit faster.
if I open the oil cap while engine is running, the noise stops immediately.
failed PCV?
Yes, i think the issue is that valve. Its got some orange rubber and the spring that helps it to open and close when idling and accelerating. And this issue makes the car to burn a lot of oil, and the smokes if you drive for a long time. And so to avoid excessive burning of oil i always have to drive a bit faster.