Ask the Mechanic: Why do I get conflicting engine oil level readings?

Engine oil

Paul Kaganzi

Hello Paul, I recently checked my oil level and it was way below the maximum level so I topped up and checked again. It was still below the maximum level so I added another half litre and checked again. This time, the level was way above maximum. Will this damage the engine? Should I have the extra drained off and how accurate are dipstick readings?


Hello Mukasa, having excessive amounts of engine oil after top up can lead to engine damage when you drive. This is because excess engine oil leads to unusual oil pressure build up, foaming and reduced lubrication efficiency or timely flow of oil around the engine. This can alter engine performance and protection.

It is crucial to consider draining the excess engine oil until you get to the right level. The irregular engine oil level readings you keep getting could be due to use of a damaged oil dipstick or its chamber. So, have your car’s dipstick examined to make sure it smoothly goes down the dipstick chamber without meeting any obstruction and seats fully in its sheath. It is also important to measure the engine oil correctly when the car is on a level floor.

Should the floor be uneven, the oil readings will not be correct. So, different floor surface gradients will give you conflicting oil level readings.


Hello Paul, on a conventional 4WD estate if the rear differential fails, can the car be safely driven by engaging 4WD and using the remaining power to the front wheels to keep going? Joseph

Hello Joseph, when the rear differential of your 4WD estate breaks down, your ability to continue driving safely will depend on the extent of damage and the design of your car’s 4WD system. While it is possible to engage 4WD in order to re allocate drive to the front wheels in order to allow the car to continue moving, you may need to disengage the rear propeller shaft from the rear differential box and gearbox. Failure to do so may lead to damage of the gearbox.

Disengaging the rear differential propeller shaft could cause some vehicle handling issues, depending on the car 4WD design.

Skidding and loss of control may happen when turning fast through corners as both of the rear wheels will be moving at the same speed instead of moving at different speeds to accommodate the different turning radius (distances) between the rear left and right wheels.

For example, in a corner, the wheel closest to the corner or roundabout has a shorter turning radius (distance) compared to the wheel farthest from the corner. The differential system allows each of the wheels to move at different speeds in order to avoid skidding or handling issues.


Hello Paul, the fuel gauge of my Toyota Belta 201 does not work and wiring mechanics have been unable to solve the problem. Sometimes, the tank shows it is full while other times it shows it is empty even after refuelling. Mechanics have even changed the dial to no avail. What could be the problem?


Hello Victor, the irregular and intermittent performance of your Toyota Belta fuel gauge despite replacing the instrument cluster (what you referred to as the dial) may be due to the failure of any one of the other components in the fuel metering system. You may have a malfunctioning fuel sender, which is supposed to measure the fuel level and relay this information to the fuel gauge in the dashboard instrument cluster. If this fuel sender unit fails, it causes erratic or false fuel level readings.

Your Belta may also have wiring circuit failure or connectivity issues between the fuel sender unit and fuel gauge in the instrument cluster.

Loose or broken wires, corrosion damaged contacts, grounding or earthing issues can all contribute to connectivity problems and failure of the fuel metering process.

You also need to find a garage with a good mechanic to investigate which of these areas are causing the problem.

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