Oil Pump

[DonovanPorter]

can some explain to me how the oil pump works on a e46 318?

http://www.realoem.com/bmw/showparts.do?model=AL32&mospid=47631&btnr=11_2064&hg=11&fg=30

and what be the chances of the going faulty ?
what else could contribute to loss of oil pressure besides a leak ?

 

[P1000]

http://www.motoetc.com/home/2010/03/eccentric-oil-pump/

 

[DonovanPorter]

awsome thanks P1000 understood

chance of failure would seem minimal