Thursday January 23 2014

Safety: Why you should pay attention to the car’s oil

By Mustafa Ziraba

The materials, seals and finishes used inside today’s engines makes them more dependable than ever. Nonetheless, a variety of cars on Ugandan roads do consume oil. See, the only fluid that engines should consume is fuel as all other systems that have fluids in them are closed systems. I shall qualify that though by saying it should be noted that a degree of oil consumption should be anticipated in all engines. What is considered normal or acceptable, however, will vary from one engine to the next. One thing all oil consuming engines have in common is that they are higher mileage engines. Let’s see why they may be consuming more oil.

Driving style
Ridiculous as it may sound, driving style has an effect on the rate of oil consumption an engine does particularly engines that have the vice. Revving your engine too high increases oil consumption as the higher your usual revolutions per minute (RPM) is, you put extra pressure on the seals and gaskets and some of the oil finds its way around and gets burned away in the combustion chamber.

Oil leaks
Oil leaks are the most obvious cause for low engine oil level. Seals and gaskets shrink, get hard and start to leak. Small oil leaks cause problems but rarely account for much oil loss. Large leaks often come from pressurised areas of the engine. Oil pressure switches, oil filters that are loose, rear main seals and head gaskets can cause considerable loss. Sometimes oil is blown under the vehicle by the air current.

This may make the leak less noticeable, as there may not be drops under the engine. It is relatively easy to become aware of such leaks, as the oil leakage spot is visible on the engine and many times will leave stains or wet spots at parking spots. In fact, looking at any public parking spaces or your very own parking space, you are bound to see engine fluid drop markings in all sorts of shades. Looking beneath your car is an excellent way to be pro-active in keeping your car operating properly.

Through the exhaust
If there are no oil leaks, the oil must be going out the exhaust. For this to happen, it must go past the piston rings, the valve seals, or through a vacuum leak on the intake side of the engine. Engines with this type of leak will have one cylinder with wet oil deposits on the spark plugs. The engine may operate fine but uses oil albeit poor fuel economy.

Broken parts
Piston rings can also sometimes become stuck, typically on engines that are not operated for several months. Engines with broken or stuck piston rings often do not use oil when driving around town because RPM’s are lower and there is less oil splashed on the cylinder walls for the rings to control. On the highway, or during high RPM operation, though the engine can use oil quickly as it passes the rings and is burned in the combustion chamber.

You likely will not see oil smoke out the tail pipe, although a person in a car following you may be able to notice a slight amount. If the rings are broken, replacement is the only fix. Valves and valve guides wear as the engine operates. This creates bigger clearances where oil can flow down the guides into the combustion chamber. Oil seals on most engines limit the amount of oil but these seals can get hard and fail. Badly worn guides can also prevent the seals from working properly.

It is possible to operate an engine for many thousands of kilometres even though it is using oil. Just be sure to check it often and keep it topped up to the full mark. When the budget allows, then you can look at repairs or another car. Most oil loss problems can be prevented with consistent.