I would say at least once every 3-4 months.
Whenever it gets dirty.
Every 15,000 miles.
How often should you change the fuel filter?
Every other oil change, drain water valve once a month.
Every 4000 miles. Change it when oil is changed, along with oil filters
Change the oil filter every time you change the oil.
You should change a furnace filter every 2-4 months.
Diesel, once a year or 15,000 miles. Gas, no service required. (it is part of the pump in the tank)
when it is dirty
every 3000 miles
My garage have changed it at 5213 mileage, which seems very low to me? Any ideas?
Diesel smoke is often caused by fouled injectors, in which case the smoking can be cured by pouring a dose of good injector cleaner into the fuel tank on the next fill-up, and change the fuel filter, too. And change the engine oil and filter!