Knowing if your car uses too much oil is crucial
As a result of wear and tear, cars are likely to use more engine oil as they get older. Although higher oil consumption is a common problem, when it’s ignored, it can cause major damage to your engine. In this article we take a closer look at the most common causes of high oil consumption and how to prevent it.
What Is Normal Oil Consumption?
As much as we’d like to say there’s one definitive answer, there isn’t. While higher oil consumption is relatively common, car manufacturers don’t give exact guidance as it often depends on vehicle make and how it’s maintained. While a set rate may be normal for one engine, that number could be excessive for another car.
For example, BMW says it’s normal for some of its cars to burn almost one quart of oil in less than 1,600 km. At the same time, GM says normal oil consumption can be around one quart for every 3,000 km on a properly driven and maintained car.
Kia is another good example where oil consumption tests indicate it also needs one quart of oil for every 1,600 km. According to one driver overseas, they needed to add about three quarts of oil every six months or every 8,000 km in their Kia Soul.
Generally speaking, most engines with fewer than 80,000 km really shouldn’t use much more than a quart of oil between oil changes, unless the manufacturer stipulates otherwise. And, once an engine gets beyond 120,000 km, and past 160,000 you can expect a higher oil consumption.
Common Causes Of High Oil Consumption
If your engine needs a quart every 5,000 km or less, that could be a sign of a leak or internal engine problems. Here are some of the most common causes of excessive oil consumption.
Bad Piston Rings
Piston rings keep a tight seal as they move up and down the cylinder. If they are worn, the seal may not be as tight, resulting in oil leaking into the cylinders. Piston rings are exceptionally strong and long-lasting so when they are worn, your engine might be in serious trouble.
Intake or Exhaust Valves
Intake valves allow the fuel and air combination to enter the engine cylinders where it combusts. This process produces exhaust fumes that need to exit the cylinder through the exhaust valves so if these are worn, oil can also leak into the cylinders where it can burn up.
Faulty Positive Crankcase Ventilation Valve (PCV)
Ever notice oil levels are dropping but there’s no visible sign of leaks? If this happens, the oil is more than likely being burned up in the engine. One potential cause is a faulty Positive Crankcase Ventilation Valve (PCV) which allows air to escape, releasing pressure from the crankcase. If this valve has been damaged or worn, the pressure build-up could result in oil leaking into the combustion chambers.
Leaking Oil Pan
The oil pan is often the first place to spot an oil leak. It will not only show low oil levels but it will often leave a puddle of oil underneath your car when parked.
This happens because the oil rests in the pan when the engine is turned off. If there’s a leak, the oil will escape and fall onto the road surface. Thankfully, this is a relatively easy problem to fix which often requires a new gasket or oil pan.
Driving Style And Habits
The way you drive and how hard the engine has to work can also affect oil consumption. Overworking, the engine at a low RPM or consistently driving at a high RPM can make the engine burn more oil and fuel faster than normal.
Skipping Oil Change Services
You should never skip an oil change service as the oil will become dirty and contaminate the engine parts and wear them down faster. Consult your owner’s manual to find the recommended oil change intervals for your vehicle.
When oil leaks into the combustion chambers, it will burn out and while might not always be enough to produce blue smoke from the exhaust, it’s often noticeable when checking the car’s dipstick.
In addition to excess smoke, you may notice oil droplets or puddles underneath the car and sometimes a drop in overall performance and fuel consumption.
What To Do When You Have Higher Oil Consumption Than Normal
Smoke coming from your exhaust with a blue tint is a definite sign that your car is burning oil and not just fuel. If oil is leaking into the combustion chamber, you could be faced with a serious problem that needs addressing as soon as possible.
Even if you don’t notice smoke and your car is consuming too much oil between oil changes, it warrants the services of a professional. While it may only need a simple tuneup, the issue could be more serious requiring a more in-depth service, repairs or replacements.
Considering the lack of uniformity around oil consumption, the best approach is to do the following:
- Check your oil levels regularly
- Get a mechanic to look for leaks if your engine is using too much oil
- Make sure you adhere to the recommended oil change intervals
- Use high mileage car oil
- Check for leaks often as even small leaks can eventually cause serious damage to your engine
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