Oil and Fuel Consumption Problems

The most common reasons for excessive fuel consumption include the driver’s driving habits, driving too fast, high-speed air resistance, and head winds.

Excessive Fuel Consumption:

• Bad fuel injectors or pump. Injection Pump Failure.
• Blocked air cleaner assembly.
• Missing gas tank filler cap.
• Loose or leaking fuel lines or fittings.
• Incorrect rear axle ratio. How to find rear axle ratio (video).
• Excessive clutch slippage.
• Excessive engine exhaust system back pressure.
• Dragging brakes or low tire pressures that cause exxcessive rolling resistance.
• Incorrect valve adjustments.
• Worn rings, pistons and burned valves causing loss of cylinder compression pressure.

Excessive Oil Consumption:

• Diluted or bad oil.
• Incorrect oil viscosity.
• Worn pistons or piston rings.
• Excessive crankcase pressure.
• Excessive valve-to-valve guide clearance or bad valve guide seals.
• Excessive connecting rod clearance.
• Internal turbocharger seal leakage.
• External gasket or seal leakage from crankcase problems.  Inspect oil level, breather and hose whenever a seal or gasket leak occurs.

The Top Two Engine Killers are a lack of oil and a lack of coolant.  Read more here.