One likely little-known fact about cars, trucks, and SUVs is that most engines burn oil. In fact, the majority of auto manufacturers consider the loss of a quart of oil every fifteen hundred miles or so to be acceptable. Between oil changes! That may come as a shock, but if your engine is losing oil every so often and the oil light is shining from your dashboard, it actually could be a natural occurrence. That is why it is important to check your oil regularly – every week or two – to make sure that your engine does not run too low on oil.
But that can lead to a major misunderstanding. If you are constantly adding oil to your engine, doesn’t that mean you really don’t need to change the oil? Or at least not as often? After all, the oil you add is clean and fresh. Why would you need to do anything more?
Why an engine loses oil in the first place
Your vehicle owner’s manual makes all sorts of suggestions for car maintenance. Tips to take care of the tires, fix a blown fuse, and check the levels of a variety of car fluids, including the oil. Assuming you follow the manufacturer’s recommendations, you might notice that the oil on the dipstick does not always reach the “full” mark.
That is because your engine, like many engines, most likely burns oil. That means, oil that is in place to lubricate all of the moving metal components inside your engine disappears in the process. Why? Well, when the pistons move up and down in their cylinders, the piston rings that seal off the combustion chambers exert force against the cylinder walls. The more force, the more efficient they will be at sealing. But when the piston rings wear out and get weak, oil blows by the rings and enters the chambers where it burns off with the fuel.
Exacerbating the situation is a move by auto manufacturers toward lower-tension rings and lighter-weight synthetic oil to promote better fuel economy. Lighter weight oils can more easily slip by the piston rings, therefore they tend to burn more oil normally than older vehicles that relied on thicker, high viscosity oils.
Other causes of oil loss
“Burning oil” is not always a natural phenomenon. Sometimes it happens because of worn out parts (including worn piston rings). It is also not the only cause of lost motor oil. A fluid leak can cause your engine to lose oil as well.
Engine oil leaks come in one of two varieties: external or internal. External leaks can be caused by worn out gaskets that seal the seams of an engine. Internal leaks can be caused by bad gaskets too, but they can also be the result of a PCV problem, faulty valve seals, or some other issue.
When an engine loses its oil because of an external leak, you will most likely see a puddle of oil on the ground or in the engine compartment at some point. An internal leak is harder to identify. In either case, you can detect oil loss by checking the dipstick on a regular basis.
Adding oil vs. changing the oil
When an engine gets low on oil, it is a common and proper procedure to add more oil, to “top it off.” It is really quite simple: to top off your oil, you only need to identify (and acquire) the correct type and weight of oil, remove the oil cap on your engine, and pour in enough fresh oil to reach the full mark on the dipstick.
But that is where the similarities between adding oil and changing your oil leave off. Aside from the fact that you are putting oil into your engine, an oil change is altogether different from a top-off.
When your oil is changed, all of the old engine oil is drained through a port in the oil pan beneath the vehicle and collected for recycling. The oil filter that traps impurities in the oil is removed and replaced during the operation before new oil is installed. So, whereas topping off simply adds new oil to what is already inside your engine, an oil change completely replaces what is in there.
Why change your oil?
To appreciate the difference between an oil change and a top-off, it is important to understand why your oil needs to be changed in the first place.
As oil cycles through your engine, heat and shear stresses cause it to break down and wear out. When it does, it thickens up and becomes less effective at lubricating engine components and reducing friction and heat. Contaminants – water, dirt, debris from component wear – also build up in the oil. What’s more, oil additives (put in the oil by chemists in order to improve viscosity, prevent corrosion, clean engine deposits, and other functions) lose their effectiveness.
So, while some drivers may be under the misconception that keeping the oil topped off (by adding fresh oil when necessary) is the same as an oil change, that is just not true. When oil gets old, it doesn’t need to be topped off. It needs a transfusion – a complete oil change.
How often should you change your oil? That question is answered differently by every automaker. You should always follow the vehicle manufacturer’s recommendation for the oil change interval. Where one engine might call for an oil change service every 7.5K miles, another might require it every 5K miles. If you are paying attention to the manufacturer’s recommendation for “special” or “severe” driving conditions, you might find that the suggestion is for an oil change every 3K miles.
Now, in between those oil changes, you might just find that your oil level gets low. That is when you top it off. If you suspect that there is a problem leading to the low oil level, make sure to have a qualified technician at a trusted repair shop take a look. And make sure you do not skip oil changes. Have your oil changed on time.
Columbia Auto Care & Car Wash | Author: Mike Ales | Copyright
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