Dave: Based on your sig it looks like you're in the diesel/retail business. I've always been curious about the life cycle of oil filters in on-road engines. In the marine world we run them in our medium and high speed engines on average 500 hours. The main difference is that these engines are driving generators, 100% duty, running at constant speed with various loads. I checked the hours on my truck engine last year @ about 20,000 miles and came up with about 500 hours. I'll assume that Cummins did extensive research and was confident allowing the (Schedule A) 15,000 oil and filter change interval on the 5. 9 HPCR engine, with plenty of wiggle room. I will also assume that the synthetic Stratopore media is essential to that extended interval. The 6. 7's with EGR have had their intervals sharply reduced. I've had mechaics tell me that oil filters actually filter better after they have been in service for a while. In the end, it looks like the interval should be based on the truck you have and how you drive. I've been changing my oil/filter and fuel filter at 10K, nice round number. Further thoughts from TDR members will be appreciated.
I don't have any first had experience with marine applications other than small Hinos on the old 3288. But the way I see it, the marine engines typically put more hours at a given time on at once. Not that matters, but with marine applications running at a constant load/ speed and the varying loads seen by the light duty trucks makes me wonder.
In our old race car program we could clearly see the immediate effects of trying to stretch out filter changes. While a dirty filter technically filters better due to the media becoming loaded, at some point, flow is compromised. Most engines have a bypass built in to avoid oil starvation. When this circuit is active, filtering virtually stops.
Also, when cutting open filter elements on our tow vehicles that spent thousands of miles at a constant 60mph, the filters were much cleaner than the trucks that had many stop and go trips.
We have had filters fail, and one of the causes we are sure is heat cycles. The media had lower miles, but almost all in town driving. Lot's of stop and go. It just beats the filter to death. Heat and cool cycles damage more than it's share of other parts. I don't think it's a stretch to assume oil filters are subject to similar conditions.
I remember I found a '68 GTO in an Arizona barn as a kid. When I went to get it running, the filter was just nasty. Apparently, just sitting with nothing flowing through it was damaging to the filter.
What does all this mean? I would follow the manufacturers recommended guidelines for filter and fluid changes. I would do them more often as power is turned up, or more extreme use is encountered.
So, I just err on the side of caution.
Dave
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