Engine's been a bit noisy of late....a sort of tappetty sound coming from the top somewhere that makes it sound a bit like a diesel. My independent says its normal and nothing to worry about. Research suggests it's the valve lifters, air has got in somewhere and that they have to be bled. I know how to do this. Question is, should I need to worry about this? If I bleed them, and the noise goes away, will it come back? Is the revving at idle a permanent 'cure'?
I know this subject seems to have been covered quite widely on the net, but curious as to what you guys might have to say.