Saturday Science Sessions – Why Your Car Needs An Oil Change

Everything that we use on a daily basis at some point needs to be serviced, including vehicles! Cars use many important fluids, but oil for the engine is a lifeline. Changing the oil in a car is critical for maintaining the performance of a vehicle – I have been changing the oil in my car every 10 000 km for the last 12 years.

While gasoline is used for combustion in the engine, the oil is the essential lubricant, which facilitates metal-on-metal contact. The engine in a car relies on the movement of pistons that move up and down in cylinders, both of which are made of metal. The metal pistons need to be able to move freely within the metal cylinders without excessive friction. Friction can generate a lot of heat, which could cause the engine to seize. The engine oil minimizes the amount of friction in the engine components.

New oil contains additives that improve its performance like dispersants, rust-combaters, and friction reducers. Over time, these additives wear out and reduce the quality of the oil. Furthermore, in order for the engine oil to do its job properly, it needs to stay clean. Over time, the oil accumulates dirt and breaks down. The oil filter is only effective to a certain limit. If the filter clogs from too much dirt, the oil bypasses the filter through a relief valve. Dirty oil is thick and abrasive, so it causes more wear on engine components. Solid particles of dirt and grime in the oil settle to the bottom of the sump.

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Changing your oil is actually really simple:

1. Lift your car – in order to access the oil pan and the filter, the vehicle needs to be jacked up. Be sure to check the owners manual for proper placement of the jacks. Also chock a rear wheel to prevent the car from rolling back while the front end is raised.

2. Open the hood of the vehicle and unscrew the engine cap to allow a path for air to flow while the oil is draining.

3. It is time to get under the vehicle! Take a look for the oil pan and locate the oil plug, which will be on the bottom of the pan. This plug is where the oil is going to drain from so place another container on the ground under the oil pan to catch the oil as it empties.

4. Remove the oil plug using a socket or adjustable wrench. You may have to play around with access under the car to get good leverage on the plug and turn counter clockwise (lefty loosey) to untighten it. Once the plug has been loosened with the wrench, continue unscrewing by hand and anticipate that the oil will start to flow at an angle as soon as the plug is removed. Then simply wait until all of the oil drains from the pan. Once the oil is drained, re-install the plug in the oil pan. First by hand tightening and then finish with a wrench or socket. (Replacing the plug immediately is a good idea – if you forget and then pour new oil into the car, it will all empty onto the ground through the oil pan!).

5. Next up is looking for the oil filter. I have found that oil filters can be located in awkward positions. It may be a good idea to consult the owners manual to get a general idea of where the filter is. Once you find the filter, again unscrew counter clockwise by hand (it is usually only hand tightened). If not possible by hand, you can try a filter wrench. Make sure that the pan used to drain the oil is still under the car because more oil will fall once the filter is removed.

6. Get the new filter ready for installation by rubbing a bit of oil around the rubber gasket on the top of the filter. This helps with lubrication and the seal. Install the filter by hand and screw to tighten.

7. The last step is to fill the car with new oil. Add new oil in the filler spout under the hood (amount as specified in the owners manual). Start the engine to get oil moving through the system. Shut the car off and check the oil level with the dip stick under the hood to make sure the oil level is within the correct amount.

8. Properly dispose of the waste oil.

Routinely changing your oil can significantly extend the life of your car. Plus, it is a good excuse to get your hands dirty!

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