Life can be hard for a technician. Learn anything under the hood about cars and risk multiple face palms at the things that ordinary people seem vigorously determined not to know.
Here are three of those things that that most people don't know but really should.
Low tire pressure can kill you
People are likely to be aware of at least a few low tire pressure effects -- underinflated tires make for lower gas mileage and uneven tread wear, overinflated tires absorb less shock and lead to a bumpier ride, etc. -- but the hidden dangers of low tire pressure effects aren't as widely known as they ought to be.
First of all, tire testing experts point out that tires only really start to "look flat" after they've lost 50 percent or more of their recommended air pressure. Most people wouldn't know a tire that's 25 percent flat from one that's perfectly pressurized.
Combine that with safety concerns like decreased steering ability and the extra heat that can build up inside underinflated tires, and you've got the perfect recipe for a high-speed wreck. What's more, the National Highway Traffic Safety Administration (NHTSA) found that 66 percent of the accidents caused by tire problems involved passenger cars, so the safety of your family might depend on the accuracy of your tire pressure gauge.
A bad jump-start can put your eye out
It's a simple procedure that you've known how to do for years. Connect positive to positive, negative to negative and then let the juice just flow, right?
Nope. Wrong. Blindingly, explosively wrong.
The issue here is the little electrical arc that happens when you shut the jaws of that final cable clamp. Some conditions, like extreme temperatures, can cause electrolysis of the water inside your lead-acid battery cell and release a mist of hydrogen gas that can turn into a nasty explosion with a single spark.
There are a few other, less common car battery dangers, but the Detroit Agency for the Blind and Visually Impaired reports that the number of people who suffer injuries from jump-start explosions is somewhere between 6,000 and 10,000 in a year. Tell people to connect that fourth cable clamp to the chassis or some other bit of metal instead of the battery and they're more likely to keep their eyesight.
You change your oil too often
Believe it or not, 3,000 miles is often far less than the life of your oil. There are exceptions to this, like engine systems that depend on oil pressure to regulate the timing chain tensioner, but in most cases you'll likely get double or more the service out of modern oils than conventional "wisdom" has conditioned us to expect.
Thanks to today's multi-weight, detergent and synthetic oils, even severe service intervals can stretch to 5,000 miles or more. Normal commuter driving will commonly give your oil a 7,500 mile interval before it begs for a change, and some synthetics remain effective for up to 15,000 miles of not changing oil.
Of course, what you tell people is your prerogative. According to auto service veterans, the 3,000 myth only lives on because it keeps the service bays full at oil-and-lube joints. Maintenance titan Jiffy Lube, however, has recently announced an effort to change its myth-propagating ways, but your mileage may vary based on a store's location and the time of day.
There you have it! Spread the word, the world could always use more knowledge.
- Car Talk, Service Your Car, "Car Talk Service Advice: Tire Pressure," http://www.cartalk.com/content/service-your-car-13
- Fox News, "Study finds low tire pressure a factor in many crashes," FoxNews.com, May 14, 2012, http://www.foxnews.com/leisure/2012/05/14/study-finds-low-pressure-factor-in-many-crashes/
- The Straight Dope, "Is it dangerous to jump start a dead battery? (Especially the way most guys do it?)", Cecil Adams, September 30, 2005, http://www.straightdope.com/columns/read/2617/is-it-dangerous-to-jump-start-a-dead-battery
- The Nordic Group, "Motor Oil Myths and Facts," May 17, 2002, http://www.nordicgroup.us/oil.htm#Oil Change Intervals
- Edmunds.com, "Stop Changing Your Oil: Breaking the 3,000-Mile Habit", Philip Reed and Ronald Montoya, August 24, 2010, http://www.edmunds.com/car-care/stop-changing-your-oil.html