That's a question that should generate a bunch of opinions. The correct answer, of course, is when it gets dirty or plugged. As long as the filter is clean and passes fuel and filters trash as good as new, then you can leave it alone. On the highway trucks and larger diesels it is common to change the oil and fuel filter about once monthly or about every 10,000 miles. Even then, on rare occasions, you will get some water in a tank of fuel and have to change the fuel filter when that happens. On my LMM, I feel good changing it every 6,000 miles as long as I don't detect any water. Actually, it's as much personal preference as anything. I don't believe the life of the engine would be affected if you changed it at 3,000 or 8,000 as long as the filter was still passing the fuel and filtering the trash properly. And if a filter starts to plug up or has water in it, you don't have any trouble telling it.

 

I would change it every 6 to 7 thousand miles. I notice that after it hits about 6 thousand miles...my fuel mileage suffers until I change it.

 

Thanks for the info..............

 

Ya never know what kinda fuel you'll get at some stations..So, just to be on the safe side, mine gets changed every 4 to 7k miles.

 

I change mine every oil change or everytime i notice a differnce in perfomance