Had my Astra SRI 2002 for two years.
Am proud to have changed my own oil for the first time last weekend .
Found that the filter cartridge had been jammed in crookedly
and the nipple bit had broken off .Would not have been filtering at all.
I suspect they did not put oil on the o-ring and forced it in.
It would have been noticeable but was ignored .
Will be doing my own from now on .
Using 10-40 .
Also while under the hood found I have a Zafira chip mod of some sort .