CAR CLINIC | Driving habits that will help extend the life of your vehicle — and those that won't

Driving habits have a major impact on a car's longevity, reliability and fuel economy. Our resident mechanical expert Gerrit Burger looks at a few that will keep your ride on the road for longer.

Let's look at some good ones first. 

• Be gentle on the throttle while the engine is cold. Engine oil is thicker than the ideal viscosity, the clearances in the engine are bigger than the optimum, the fuel regime is still on cold running settings, the transmission oil/fluid offers extra resistance to flowing, so let the engine get to normal operating temperature before you put your foot down.
• Let a turbocharged engine idle for 30 seconds before you switch it off after a hard run in hot weather. Even on a naturally aspirated engine the exhaust valves will thank you.
• Make it a habit to check your dash gauges regularly. For instance, if an engine which has always maintained a steady coolant temperature suddenly shows an unusually high reading, something is wrong and should be investigated promptly. In the case of a significant coolant leak, you may be minutes away from a blown head gasket or worse. Unfortunately, some entry-level cars have substituted a temperature gauge for a warning light, a woeful case of false economy. Similarly, a fuel gauge which behaves abnormally (perhaps getting stuck at a certain level) is something you don't want.
• Check your brake lights, taillights, indicators and parking lights regularly. Bulbs can easily fail without you noticing and, in the case of indicators, this can be dangerous.
• Get to know your car. Study the owner's manual. It contains vital information about oil grades, tyre pressures, types of antifreeze, replacement intervals of drive belts, and so on. Make a photocopy of the meanings of the warning lights and keep it in the glove compartment. You may need it. Don't rely on a workshop to look after your car. You cannot expect hard-pressed workshop staff to have the same commitment to the vehicle as you do.
• At filling stations check which fuel nozzle the attendant puts into your car's filler tube. Attendants are well aware of the danger of putting petrol in a diesel vehicle or vice versa, but they are also human and mistakes do occur. Supervising the filling of the tank also allows you to ensure the nozzle is fully inserted into the filler tube so filling will stop when there is still the required air space left above the fuel in the tank. Filling to the brim is not recommended.

 Turning to bad driving habits, the following are a few from a lengthy list.

• Riding the clutch, that is, using the clutch pedal as a footrest while driving, is a sure way of hastening the demise of the release bearing. So is keeping the clutch pedal fully depressed while waiting at traffic lights, something that is not doing the thrust bearing on the crankshaft any favours. Much better to put the gearbox in neutral and let out the clutch pedal fully. Slipping the clutch to keep the car stationary when stopped on an incline is a very effective way of destroying a clutch plate. I always cringe when I see a vehicle alternately surging forward and rolling back while waiting at a traffic light because the driver cannot be bothered to put the gearbox in neutral and apply the handbrake.
• Revving an engine with the gearbox in neutral puts such inertial forces on pistons and conrods that the engine control modules on some modern cars will not allow it. Under no-load conditions there is no cushion of compressed air on the upward stroke of the piston to lessen the tremendous force needed to stop the piston and turn it around at top dead centre. To hear a driver “blipping” the throttle (for “fun”?) or a mechanic revving the daylights out of an engine is also cringeworthy. There's far less stress in an engine working lustily, even at highway cruising speed, than in one that is revved under no-load conditions.
• “Lugging” an engine, that is, making it work hard in too high a gear, is a habit which falls in the realm of disastrous. It sets up torsional vibrations in the crankshaft, clutch and gearbox, inflicting terrible punishment on these components. The effect is similar to a dog shaking itself dry. In severe cases it causes jerking, known as “torque agony”, because the engine cannot deliver the torque demanded. Picture a bakkie with a trailer going up a mountain pass and the driver trying to make it to the top in fourth (or fifth!) gear. Or, in a more mundane situation, a driver turning into an upward-sloping side street while town driving and being too lazy to change down. In short, both over-revving and under-revving are detrimental to an engine.