325e oil pressure worries

[faulknern]

Hello,

I'm hoping for some expert advice on a bizarre oil pressure issue.

Upon cold startup the oil pressure light will remain on instead of going out shortly afterwards as per usual. As the engine warms up it will go out but takes at least a good 5min to do so. At this stage if I raise rpms the light will come back on. Once the engine is at %100 operating temperature the light will remain off regardless of engine rpm. Also I notice valve train seems noisy when engine is cold...no pressure is what jumps to mind to me.

My local mechanic checked mechanically the pressure while warm...which I didn't think was a good test considering the cold start nature of the problem. Oil pressure is good when warm and he diagnosed as a failing pressure switch at high pressure. I thought this was odd as my experience pressure is low upon startup and gradually builds.

I have switch on order in a few days to replace anyway, but is there a chance this could be something else?

Any help is appreciated. Thanks.