Good morning - my R56 has about 92,000 miles on it and this morning I removed the oil cap while the car was running and I could feel fairly strong pulses of air when I held my hand over the now open oil cap neck.

Is this considered normal for a healthy engine?

Thanks!

 

On every engine I've ever worked on, you were't supposed to have the oil cap off with the engine running. The rockers/valves sling oil pretty good, typically. So, I'd have no idea if that was normal or not. I could see it being a normal thing, though, considering oil pressure would cause air pressure. Combined with the rockers/valves moving, it would seem reasonable to feel slight puffs of air. However, I'm not a pro. So, maybe someone has another opinion.

Incidentally, why do you have the oil cap off with engine running?

 

+1

Yes, there is pressure in the engine that would cause your puffs, WHY WOULD YOU TAKE THE OIL CAP OFF WITH THE ENGINE RUNNING?????

 

LOL. One time, when I was much younger, I accidentally left the oil cap off after an oil change, or something. I forget what clued me in (probably started seeing smoke) but when I opened the hood, there was oil slung all over the underside of the hood. Luckily, the cap was pinned between the hood and the engine.

 

Good morning thank you for the responses. It's not it's completely crazy as it may seem if you're mostly familiar with British cars. That's a quick way to see if your upper rocker shaft is getting oil if they are already blow by issues. Car was stationary with bonnet iup already and I was curious as I have some oil leaks / oil consumption issues.

 

Now how "British" I'd consider modern Mini's to be.