A fuel leak can be caused by loose fittings. Additives in the fuel can cause the seals to go bad prematurely. The Power Stroke diesel engine, which powers the heavy duty Ford pickup trucks, had problems with fuel leaks. Most of the leaks tend to occur around the fuel filter.
The Power Stroke diesel engine has been produced for Ford heavy duty pickup trucks since the 1994 model year. It is the one of the choice engines for customers who need a strong, hardworking diesel engine in a heavy duty pickup. The 7.3-liter engine was produced from 1994-2003, and the 6.0-liter engine has been in production from 2003-present. A dual turbo version has been in production since 2008. The engine is powered by Ultra Low Sulfur Diesel (ULSD) fuel.
Leaking fuel may come from the fuel filter area. The fuel filter is housed in a canister. The canister is known as a fuel bowl. The 1998-2003 7.3 Power Stroke engine employ the same fuel bowl design. Evidence of a fuel leak will display itself as fuel coating the front axle or puddling in the engine bay.
The fuel drain valve may the source of the fuel leak. The fuel drain valve is located on the fuel bowl. The valve itself may not be faulty, but o-rings in the valve can go bad. The drain valve has three o-rings in it. A fuel drain line leads from the rear of the fuel bowl on the top of the engine and ends under the passenger side cylinder bank. The drain valve is located directly over the front axle.
The early Power Stroke engines were introduced after the sulfur levels in diesel fuel was reduced from 5000 to 500 ppm (parts per million) in 1993. This introduced the Ultra Low Sulfur Diesel Fuel to the public. Diesel fuel has aromatic properties, which are materials which causes the o-rings to swell while they are in service. The swelling of the o-rings creates a seal in the fuel system. The ULSD contained fewer aromatics and the o-rings will not swell as a result. The result is the fuel systems leaked fuel.
