Oil leak My 2002 Nissan Fronrier XE V6 Crew Cab with 108,000 miles on it has suddenly developed an engine oil leak. When I backed up and parked on a slight incline oil dripped for several minutes leaving a oil spot of the concrete about 6 inches long. The oil appears to be dripping from the rear of the motor where it mates to the automatic transmission bell housing.

Two very likely sources for engine oil. You could have a valve cover leaking or a rear main seal. The best way to check is to trace the source of the oil. This requires a very thorough steam cleaning to remove all the old oil. Place an oil dye pack in the oil (about 3.50 at Napa and other parts stores). Run the engine for about 15 minutes and use a blacklight source and a mirror to check the back of the engine below the valve covers and closest to the firewall. Check out how the fresh oil floureces in the blacklight source by checking your dipstick for the color of the glow. If the back of the engine is dry and clean and your puddle is still glowing from between the engine and the transmission, you have a rear main seal and the transmission will need to be removed to change the seal. Spend the time on the diagnosis before you spend the money.

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