Club 80-90 Forums

I fitted a new oil filter a few weeks ago.It was running fine for about a month,now it has started buzzing for about a second or two every now and again. The oil light comes on at the same time. The buzzer stops if I decelerate or put the clutch in.It doesn't do it when cornering or downhill. I have checked the level and it seems fine.
Any ideas whats causing it ?

1988 1.9 Diesel, reconditioned and fitted 4 years ago.

What grade oil did you put in?
It could be too thin.