After a 2hr drive down to London last night, I noticed a distinct ticking noise coming from the top of the engine as I parked up. This is an 525 with the M50 engine and hydraulic lifters and I've never heard such a tick-tick-tick noise coming from the top of the valve cover area before. Normally the car is near silent (ignoring the normal noise of the fan spinning) after it has warmed up.

I took a look around but didn't see any obvious leaks or hoses hanging loose. The oil level is fine. Water temperature and level also fine.

How can I check whether any oil is actually being pumped up to the valvetrain? I tried to look down into the valvetrain through the oil filler hole while the engine is running, but there is the splash panel over the camshaft and I could only just see a tiny bit of the spring-deck area. Couldn't see any oil flowing around there. Should I be able to see any oil anyway? The only thing I noticed was a fine mist trying to escape from the open oil hole. I'm guessing this is normal, but the ticking noise is not.

I am tempted to remove the valve cover to check for further clues. I suspect it's the supply up to the top that's the problem though. So any ways to check the oil pump is working? The oil pump is in the pan on an M50, yes? Should I take the oil pan off and check the pick-up pipe? Your thoughts would be very welcome.

Cheers,

Mas