How are you interpreting your engine hour data?

[PJay9]

WOW! I just went and found the hours and figured it out... 34. 9 is my calc. Now here's he rub. The Dually was my driver to work city streets for a year before I retired and is my run around truck as well for projects and meeting the guys for coffee. With 77K on the clock about half of that milage is trips with a camper... I don't hang around on the road, my gps gave me my stats on the last trip... moving time was over 39 hours and speed was 51mph which adds up to just short of 2000miles driven, My odometer reads just over 2100 miles driven, so everything is close. If the GPS can't find a sat is stops figuring until it comes back and it did. So I am happy with those stats. So that says to me that the city driving stuff is below 35... DAH!!! Most streets and traffic it is... SO Dodge figures that for "heavy use" ... . I don't idle except at a light and when I cool down maybe a minute or two after freeway speeds with a load and some warm up now that it is cold... It just doesn't add up! I am going to figure my other stats and add up the hours the key is on as I write that down each fuel up. . should be interesting.

 

[rbattelle]

Any particular reason?

I experimented a little with a few different intervals and 300 hr happened to seem good in terms of the accumulation of visible dirt on the filters.



Ironically, for me 300 hr is almost exactly 10k miles, which is the factory interval. Go figure.



Ryan

 

[betterthanstock]

I run 300 hour fuel filter changes.

I think it would make more sense to change fuel filter by the number of fillups.

After all, you are filtering fuel, so the more you burn, the more changes. Maybe once every 25 tanks?



The oil filter I can see doing by the clock, since if you think about it, for short trips they recommend twice as often a change, as for highway miles, which works out to an identical number of hours. Idle time still degrades the oil, sometimes more so than freeway hours.



Do I do it like that myself? No, but it seems more logical. Maybe in the future.

 

[rbattelle]

I think it would make more sense to change fuel filter by the number of fillups.
After all, you are filtering fuel, so the more you burn, the more changes. Maybe once every 25 tanks?

My logic in going by engine hours is that there's basically a constant flow rate through the filters, governed by the fuel pump flow rate. Even at idle, the fuel pump is running a (roughly) constant flow rate through the filters, and the excess is being returned to the tank. So as long as the fuel pump is on (engine running), you're passing a (roughly) fixed volume of fuel per hour through the filters, since the filters are upstream of the regulator (FCA) on my truck. [Trucks with a regulator prior to the filters might not work this way].

In other words, the fuel pump flows 100 GPH through the filters, regardless whether the instantaneous engine demand is 1 GPH or 90 GPH. [I'm ignoring any momentary engine demand >100 GPH, if such a demand ever even exists].

The oil filter I can see doing by the clock, since if you think about it, for short trips they recommend twice as often a change, as for highway miles, which works out to an identical number of hours. Idle time still degrades the oil, sometimes more so than freeway hours.

Do I do it like that myself? No, but it seems more logical. Maybe in the future.

This is why a lot of late model vehicles are coming equipped with "oil life monitors". My new Accord calculates the remaining oil life based on some function of idle time, engine revolutions, etc. Ironically, I completely ignore it and change every 3k anyway.

By the way, BTS, I like the new avatar. I giggle every time I see that little dancing banana. Hee hee!

Ryan

 

[Cattletrkr]

Changing fuel filters by anythihng other than a pressure gauge is pretty much a waste. I've had one that went 25K and another that went 500. Without a gauge there's no way to know if it's bad until it causes a problem.

I think a fuel pressure gauge is just as valuable for determining fuel filter life as it is for watchdogging a lift pump.

Having said that, any method of determining fuel filter change intervals is WAAAAYYYYY better than waiting 'til the truck quits.

 

[Okie-Go]

I have 54,372 miles and 1222 hours. Did the Math and I averaged 44. 49 mph.