Motoring: The true cost of ignoring your fuel light

To avoid stalling or damaging your car, it is always advised to keep your fuel tank at least a quarter full at all times. 

Motor experts agree in unison that driving on an almost empty fuel tank exposes the fuel pump to danger.

Apart from lubricating the fuel pump, the petrol/diesel also plays a crucial role in cooling off the pump that is constantly running so long as the ignition is on.

Risks of damaging the engine

When fuel levels are critically low, the fuel pump can start drawing in air along with the remaining fuel. 

This can cause the pump to overheat and wear out faster, leading to expensive repairs. 

Additionally, dirt and debris that settle at the bottom of the fuel tank may get sucked into the engine, clogging fuel injectors and reducing performance.

Risk of stalling

It is a common occurrence to see a motorist refueling his/her car by the roadside using a jerrican after suddenly stalling.

Losing power in the middle of traffic, especially on highways or busy intersections, increases the chances of accidents. 

In some cases, stalled vehicles can become hazards, leading to rear-end collisions.

Compromised braking and power steering

Mechanics warn that modern vehicles rely on engine power to operate key systems such as power steering and braking. 

When the engine shuts down due to fuel depletion, drivers may struggle to maneuver the car safely. 

One can imagine the risk involved if such a car is being driven on slopes or in heavy traffic.

Reduced fuel efficiency

Frequent low-fuel driving can negatively impact a car's fuel efficiency. The fuel pump relies on fuel to stay lubricated and cool. 

When the tank runs low, the pump works harder, reducing its lifespan and causing inefficiencies that lead to higher fuel consumption in the long run.

The risks of driving on low fuel far outweigh the benefits. Keeping your tank adequately filled is a simple yet effective way to protect your vehicle, ensure your safety, and avoid unexpected roadside stalling.

Dangers of overfilling your fuel tank

On the flip side, it's a common scene, especially at petrol stations, to see vehicles, especially PSVs, side-stepping on a small ramp as they shake the vehicle to fill it up to the brim. 

Just because most motorists do it, it is not recommended at all. Here is why.

Fuel overflow and wastage

Most modern vehicles have a vapor recovery system designed to prevent fuel vapors from escaping into the environment. 

Overfilling can cause excess fuel to enter this system, leading to leaks or fuel spillage, which is both wasteful and hazardous.

Damage to the Evaporative Emission Control System (EVAP)

The EVAP system helps control fuel vapors and emissions. 

Overfilling can force liquid fuel into this system, damaging components such as the charcoal canister, which is expensive to repair or replace.

Expansion due to heat

Scientifically, fuel expands when exposed to heat. If the tank is full, there is no space for expansion, which could lead to pressure buildup and potential leaks.

Reduced fuel efficiency

A full tank adds extra weight to the vehicle, which can slightly reduce fuel efficiency. 

While this impact may be minimal, consistently carrying excess fuel may lead to unnecessary fuel consumption over time.

Recommendation

It is recommended to stop filling when the fuel pump automatically clicks off. This leaves enough space for fuel expansion while preventing damage to the EVAP system. 

Ideally, keeping the fuel tank between 25% and 90% full is recommended for optimal vehicle performance and longevity.

Happy motoring.