Hey folks,

The 540i has been resting in the garage for a few days (3 days), probably never seeing less than 40 degrees. Anyway, went to start it up this evening and it turned over with no issues, but that was followed by a very loud tapping noise that eventually dissipated after a few seconds. It was unusually loud, and a little alarming. Running an Amsoil 20w50 Synthetic oil, and wondering if the weight could have had any effect on this.

Anyway, any help would most appreciated.

Top.

Sounds like your lifters collapsed. Normal for a car with a few miles and not being driven for a few days. All the oil drains out of them and they retract, like a piston.

Sounds like your lifters collapsed. Normal for a car with a few miles and not being driven for a few days. All the oil drains out of them and they retract, like a piston.

Right, right. Anything I should be worried about?

As you said, it's got some miles on it (~186k).

Nothing to worry about. If it does it all the time it's a problem, it it does it once after sitting for three days it's no biggie.