Changing a car’s oil is pretty simple – so it’s surprising it gets done wrong so often.
Sometimes, by “professionals” . . . who actually aren’t.
See that part above about “simple.”
Many places that do oil changes (such as tire shops and quick-lube joints)do not pay trained mechanics to do them. Because trained mechanics have better things to do – and because most shops can’t offer a $19.99 oil and filter change and pay a trained mechanic to do them.
Not without losing money on the transaction, anyhow.
For that reason, they have whoever they’ve hired for this duty do the job. They are often not trained mechanics and so come cheaper. While many still know what they are doing – changing oil is not rocket science – some don’t.
Also, assembly line oil change shops change oil differently than you would at home.
For instance, they often don’t add fresh oil one quart at a time, from quart bottles – as you would, at home. Instead, they use a gun that feeds oil into the engine from an industrial-sized barrel of oil. This makes sense from a shop’s perspective. They buy oil in bulk because it costs less and because it eliminates having to deal with cases of individual quart containers of oil.
But, when you refill the engine with five quarts of oil from five quart containers of oil, you know you’ve added five quarts of oil. No more – and no less.
With a gun, its different. The guy shooting it in trusts that the gauge telling him how much oil he’s added is accurate.
Assuming he checks the gauge.
If he does not . . . if he assumes . . . you could be sent on your way with an engine that is overfilled or under-filled and both are potentially catastrophic. Especially in…