Are the external lines one complete assembly from the engine to the filter and then the cooler or are they separate? If separate which line is more common to leak? I'm trying to order the lines from my parts supplier but unfortunately his diagram isn't quite clear on which part I might need.

 

They are separate. The ones from the engine to the filter are the ones that most commonly leak.

 

Ok my parts dealer shows a "oil filter hose" with two lines and two connections on each end and then he also shows a "oil cooler pipe" with two lines with a double connection on one end and two separate connections on the other end which I'm assuming is for the radiator.

I've gone ahead and ordered the oil filter hose as it was the more expensive of the two ($67).