I posted a couple of days ago that I just switched over to German Castrol 0W30 (M05075....the gold) with the over-sized Motorcraft FL1A oil filter. How long should I go with this oil and filter? This is for 1998 Jeep Grand Cherokee Laredo Inline 6 just about to hit 98K miles. Thanks.
OCI with GC?
- Thread starter jeepzj
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What is the previous maintenance history of the car? What kind of driving conditions will the car see?
Total mileage 98K. 1st 40K used dino oil (Castrol GTX, Havoline, Mobil). Switched to Amsoil syn from 40K to 80K. Did an Auto-rx treatment at 80K and been using dino ever since. 60% City \ 40% Hwy driving. I'm an average driver, never off road. Live in NJ so we get down to 10F sometimes 0F during winter, summer mostly high 80's low 90's but can get near 100F on occassion. Did 3K mile OCI with dino and 6K mile OCI with synthetic.
I'd recommend the "OCI Formula" as a starting point for service intervals
OCI = (C*)(Actual mpg)(sump in qts)(cubic inches/Hp**)
I'd use a C* of 80 for the GC and the GF-4 version of M1. I'd use a C* of 100 for the M1/EP, based on the UOA's I've evaluated to date....
**Note: For turbodiesels substitute ft-lbs of torque for Hp, since this is a better measure of engine output....
OCI = (C*)(Actual mpg)(sump in qts)(cubic inches/Hp**)
I'd use a C* of 80 for the GC and the GF-4 version of M1. I'd use a C* of 100 for the M1/EP, based on the UOA's I've evaluated to date....
**Note: For turbodiesels substitute ft-lbs of torque for Hp, since this is a better measure of engine output....
LOL I guess thats as good as any way to determinig OCI. However I think that UOA's trended over a few oil changes is the right way to go.
bruce
bruce
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