Rough Noise From M42 after 3000 miles in 10 days

[Dboy7er]

I have reconditioned this E30 pretty well and drove it 3000 miles these last 2 weeks, took a road trip with it. Anyway, It is still running strong but sounds different from before the trip. It sounds rough, but idles smoothly, no oil light, power seems the same. I did find that when I hold down the oil cap with all my weight or valve cover (when its not too hot). The noise goes away! & It sounds just like before minus the rough noise.. I though it was rod bearings, or exhaust hitting the frame somehow, but I'm just dumb founded, will a vacuum leak some where cause this noise ?

I know my VC gasket leaks into my 1st & 2nd Cly Spark plug wells & I do see oil slightly leaks from my oil filler cap. That shows at least my oil pressure must be good.. but as for the noise ?

Any help is appreciated Thank You

[E46M3Dakar]

Reading it goes away when you hold down the oil cap have you tried spraying carb cleaner or brake cleaner around the oil cap and valve cover while the engine is running. If the revs spike then I would assume the gasket is bad. Do you have a friend with a M42, you may want to try swapping the oil caps.

[Dboy7er]

Reading it goes away when you hold down the oil cap have you tried spraying carb cleaner or brake cleaner around the oil cap and valve cover while the engine is running. If the revs spike then I would assume the gasket is bad. Do you have a friend with a M42, you may want to try swapping the oil caps.

I assumed the same & I replaced the Valave Cover gaslet today, I do have 2 bolts that have bad threads so they won't torque down properly, got a helicoil kit & im just gonna have to take it off again & repair the threads that are bad. I will try the carb cleaner.. What is interesting is the fact that it idles just fine ..
Only difference is the rough noise it makes now .. I bring the revs up to about 2k & it sounds just fine silky smooth