Here's one reason to let your local auto body shop or car dealership service your car when it needs an oil change: Improperly changing the oil yourself can contaminate one million gallons of fresh water. Motor oil is insoluble, has heavy metals in it, is very slow to biodegrade and can contaminate water and hurt wildlife. Trying to save a few dollars to change the oil yourself can have environmental consequences. If you create a spill trying to change the oil yourself, just a small amount can contaminate 1 million gallons of water. By bringing your car to a trained professional, you know your car will get the new motor oil it needs to function properly and that not only will the old oil not contaminate water, it will be recycled and refined into new oil.