ive just bought an immaculate astra gsi , L reg 90k.its just had new oil and filter. it was quite warm when i viewed it so didnt get to hear it from cold even tho the guy told me it was noisy from start up. there is quite an annoying tapping coming from the engine bay, which my mate reckons is the shell bearings on the crank.(the shells went after 150k on his gte 16v)
the sound comes and goes regardless of oil temperature. (more of a tap rather than a knock) it doesnt tap any harder when under load, as im told it will if its the main/crank bearings.
my other mate (who is a fully qualified mechanic, who has done numerous nova valvers,and c20xe rebuilds) says hes 99 % sure its just worn tappets,
and that one or 2 of them are being starved of oil. is there a definative way of telling that it is the tappets, as i could manage replacing them myself , but would struggle, rebuilding the bottom end.
will the oil pump play a part, or are the tappets simply worn and need replacing. the engine is otherwise clean and sweet, pulls cleanly and is very smooth and fast.shall i get the guages out then?
help and advice really appreciated