The oil pressure on my 1976, 450SLC dropped suddenly one morning a few seconds after a cold start. The pressure had always been full gage (45psig) until this occasion when it dropped to approx 10psig after 2-3 seconds.
It now does this every time it is started and is not drivable as is.
My mechanic thinks it may be a problem with the oil pump but can't be sure until he takes it all apart ($1000).
Someone else suggests it may be the oil pressure relief valve sticking open.
Does anyone have prior experience of this problem and/or a solution?