Depends on how you drive. If you drive mostly city, with short trips, I would recommend changing it every 4,000 miles. In mixed driving I would change it every 5,000 miles. If you drive mostly city change it every 7,000 miles. Of course I am assuming you drive a 2005 or newer vehicle. You can never go wrong by following the manufactures recommendations as listed in your owners manual.
how many miles will i get for gallan petrol
Depends on the vehicle.
15 billion miles
35 Miles per gallon.
Diesel or petrol?
depends how much petrol is in the tank
Depends on the vehicle you are driving.
2668
depends on the MPG (miles per galon)
80,000 for petrol and 60,000 for diesel
45 miles per gallon
Depends on the fuel efficiency of your vehicle.