On Alfa number 15
AO Platinum Member
Join Date: Dec 2005
Location: United Kingdom
If there are any flecks of metal or larger deposits they will sink to the bottom of the sump, below the level of the pickup.
If they are not being picked up they won't get trapped in the filter. Also some of those who have had the misfortune to experience cam lobe wear have found that the metal doesn't always get trapped by the filter, it often ends up right through the engine.
The particles shouldn't be a problem if they are at the bottom of the sump, but if the oil is changed repeatedly with a pump they may build up to a point where they become a problem.
I have noticed a few times (Not on my GTV) that the last few drops of oil coming from the sump drain have been quite lumpy as well. It looked remarkably like the infamous black sludge, but I bet one of those oil pumps would not have removed it.
You will never be cool driving a Vauxhall.