Picking up some oil and a filter for my 502 MAG MPI and my oil of choice was on sale, Castrol GTX 20W50.

Also on sale, was the FRAM XG5 oil filter, so I grabbed one not thinking much about it, as it was on sale..

Read some favorable reviews about the filter, aside from being a otherwise crappy FRAM, it had great reports.

All over the box it has mention of synthetic oil usage, that it will extend mileage protection with synthetic. who cares... but does it need to be paired with synthetic oil? I would think not, but thought I would post the question here.

Thoughts on using this filter with the 502 MAG MPI?

You'll also need to use synthetic shifter fluid too. SF5.21 to be more specific.

LOL thanks... I'll run out and change it right away....

XG filters are the only Fram that did any good in this truck test, and a 502 is basically a truck motor, eh!

http://www.gmtruckcentral.com/articl...gradesheet.htm

It'll prob work just fine.

Neither would be my choice though.

My pair of 97’ 502mpi mags untouched have a tad over a 1000 hours each and run great with no issues. They have only used Mercury oil filters and the mercury Hi-Efficiency oil filters. The oil has been the Merc 25w-40 synthetic blend and for the last 4 years or so been using the 25w-50 racing 4 stroke merc oil.

what is your choice?

Don't want to turn this into an oil thread..
The local marine guru we use swears by the GTX 20W50.. I was a Merc Oil user forever, and just about to make the switch to the GTX with his recommendation and track record with the rest of our groups motors.

Mobil 1 15w-50 and Mobil 1 M1-302 filter. 5 qt jugs at Walmart for $25

I have 502mpi's also and have been using M1 for 400+ hrs in them.
Ran it in my 525SC for 300+ hrs

I use wix 51060R filter and Castrol 20w50

Its all about zinc, see if it is full of zinc, then it is fine, esp if you 502 is a 1995 or older(tappets). Mobil 15-50 is not any longer, used to be great..