First: What can you do?
In addition to replacing cabin and air filters, as well as wiper blades, there are a number of routine checks and minor maintenance items that the typical owner can perform, like checking fluids and lubricants, along with replacing belts and hoses, filters, and perhaps starters and alternators—all if nothing’s already at the point of failure.
Indeed, an AutoMD tally of DIY costs versus shop costs for some very simple procedures showed impressive savings. For instance, just replacing a battery yourself saves an average of nearly $60, or replacing a drive belt about $43.
But even for the more skilled shade-tree mechanic, any job that requires extensive troubleshooting—or the potential for diagnosing other related issues along the way—is best left to the pros.
Also, once there’s been a failure, an overheat, or a breakdown—or a ‘check engine’ light is on—all our experts agreed that DIY is off the table, and it’s time to take it in to the repair shop. If things aren’t going right, and you don’t understand the root cause, it’s a slippery slope to point blame to the next part in a system, again and again until it burns a hole in your wallet and has swallowed up every bit of your free time.
Beware the false confidence of code readers
And if we could point our fingers to a single thing that gives false confidence and courage to home mechanics of newer cars, it would be code readers. It’s easy to hook one up and obtain a simple number—a trouble code—and it's commonly believed that the code will simply tell you what part needs to be replaced. But RepairPal's Bodas, who has seen the results of owners who have “replaced every part they know of, but the problem still exists,” argues that following code readers alone is “a recipe for emptying your wallet and filling your driveway up with problems”
Replacing parts is a small part of a mechanic's job, Calkins agrees. “The question usually is, how do you diagnose any of this, and solve the underlying issue?”
Keeping in mind the skill level required, the amount of troubleshooting or diagnosis that might be needed, and the potential for costly damage (monetarily and bodily) if things go wrong, click over to page two to see the five things that, unless you have a mechanics’ certification and some years of specialized training, you should definitely leave to the pros: