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.