Oil changes: What do all those terms mean?

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Oil changes can be simple and basic, but if your mechanic discovers problems with your car during the oil change, you might get a list of terms you don't understand.

What does it mean when your mechanic says that simple oil change might cost more because of a "bad head gasket" or "o-rings"? Why do you have to choose what kind of oil to use? These terms make much more sense once you understand what they mean.

A Lube, Oil & Filter Job

Oil changes are often described as a "lube, oil, and filter" job. This means:

  • Your car will have all the old oil drained and replaced with new oil.
  • The old oil filter is replaced with a new one.
  • The chassis is lubricated.

Your vehicle's oil filter is an important part of the system. An engine full of dirty oil will not have a long lifespan. The oil filter keeps dirt, rust, and other particles out of the system. All filters eventually get dirty and have to be replaced, so it's considered a standard part of many oil change packages. Many lube, oil, and filter jobs also include checking and refilling the vehicle's fluid levels including;

  • Windshield wiper fluid
  • Antifreeze or engine coolant
  • Transmission fluid
  • Power steering fluid

Types of Oil

When you schedule an oil change, the mechanic may ask what kind of oil you have put in your vehicle. There are several reasons why:

  • You can choose between "ordinary" oil and synthetic oil.
  • Synthetic oil is said to offer better protection for your engine.
  • There are different thicknesses of motor oil.
  • Your car manufacturer recommends a specific type for your vehicle, but you may have an option between a thicker or thinner type.
  • Thinner oil may improve your car's cold starting ability in winter weather.
  • Some oil is sold as "multi-viscosity" or multi-grade.

Synthetic oil is more expensive than regular oil, but there are semi-synthetic varieties. Ask your mechanic what is best for your car, but know that "ordinary" motor oil is fine for your vehicle. You don't need the most expensive kind on the market.

The Head Gasket

Sometimes your mechanic may tell you that there is a bad head gasket which needs to be replaced. This is a problem that often turns up during oil changes.

  • The head gasket is located between the engine block and the cylinders to keep oil and other fluid from leaking into the cylinders.
  • A bad or blown head gasket can lead to problems with your engine including shaky or rough performance and reduced power.

The head gasket should be replaced the moment there is a problem detected.


Another problem your mechanic might detect is bad o-rings. O-rings are used to seal the oil filter and prevent leaks.

If you have bad o-rings, your car is probably leaking oil. This is a problem that should be fixed immediately; leaking oil is not only bad for the environment, it's also bad for your car.

Your car should get an oil change once every four months or every 3,000, whichever comes first. This regular maintenance insures your vehicle stays in good condition and can help your mechanic 

Used with permission. © 2015 Walmart. All Rights Reserved. See full legal.

Used with permission. © 2014 Walmart. All Rights Reserved. See full legal.


Important Walmart Disclaimer: Proper service and repair procedures are vital to the safe, reliable operation of all motor vehicles as well as the personal safety of those performing the repairs and those riding in the motor vehicles. Standard safety procedures and precautions (including use of safety goggles and other safety equipment, proper tools and equipment) should be followed at all times to limit the possibility of personal injury or improper service which could damage the vehicle or compromise its safety.  Personal injury could result from the failure to take adequate safety precautions when repairing or maintaining your vehicle.  Although this material has been prepared with the intent to provide reliable information, no warranty or representation (express or implied), including the warranties of merchantability and fitness for a particular purpose, is made as to its accuracy or completeness. Neither is any liability assumed for loss or damage of any kind resulting from reliance on this material and Wal-Mart shall not be liable for any loss or damage of any kind resulting from reliance on this material.  Users employ the information contained in this material at their own risk.  This material is provided only as a helpful guide and does not replace the information and instructions contained in the motor vehicle's owner's manual and product manufacturer's recommendations.  Users are cautioned to consult the motor vehicle's owner's manual and product manufacturer's recommendations for additional information and instructions.   Failure to follow the motor vehicle's owner's manual and the product manufacturer's recommendations could result in damage to your vehicle or personal injury.  Additionally, users should be aware of the applicable laws of their local jurisdiction.


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