Do-it-yourself repair work can save you time and money -- in addition to giving you a lot of satisfaction. But you have to be careful to avoid beginner's mistakes, which can end up costing you more in time and money than you would have spent farming the work out to a professional mechanic -- and sour you on the idea of ever getting under the hood yourself again.

These include:

* Randomly pulling parts before you know what's wrong -- This is a common beginner's mistake that quickly leads to frustration and an empty wallet. Doctors don't begin treatment before evaluating the patient and making a diagnosis. It should be no different with any automotive "operation." Find out what's wrong first -- then fix it.

* Attempting a repair without having a shop manual to refer to -- Easily the number two pratfall on any list of beginner DIY mistakes. Never disassemble components without knowing how they fit back together, etc. A shop manual will typically have schematics, photos, diagrams and so on -- as well as a step-by-step procedure for each repair. "Winging it" without the manual is about as bright as trying to prepare an elaborate gourmet dinner you've never made before -- without the cookbook.

* Not using the proper tools -- This is commonplace because few beginners have a full set of mechanic's tools; in particular, the often specialized equipment needed to properly perform certain diagnostic and repair procedures. Using the wrong tool can lead to physical damage of the part being worked on -- in addition to skinned knuckles and a lot of cursing. If specialized tools are required, be sure you have access to them -- and know how to use them properly.

* Not having the right place to work -- It's important to have a safe, secure area to work on your vehicle. The shopping mall parking lot isn't it. A covered space with good lighting is ideal. And if you need to raise the vehicle, make sure it is parked on a level (and solid) surface, not grass. Beginners get killed or badly injured every year when an improperly supported car either rolls on top of them or slips off the jack stands and crushes them.

* Rushing it -- Deciding to tear your car apart late Sunday afternoon but needing to have it ready to make the commute Monday morning is a recipe for disaster. And a common beginner DIY mistake. Always allot sufficient time to finish the job; don't try to emulate a NASCAR pit crew. Those guys have it down to a science and have many years of experience. You don't. Expect delays as a result of things you didn't anticipate -- such as needing to get a part in the middle of the job, or spending an hour on getting at a bolt you thought you'd be able to remove in a minute or two.

* Getting mad -- This mistake often springs from the loins of the other mistakes already listed. You've got the car's guts all over the driveway and have no idea how to get them back together. Or you lost something. Or something's not fitting right. Whatever. This kind of thing happens to professional mechanics, too. The difference between them and a ranting do-it-yourselfer is the pro knows when to step away for a minute, have a cup of coffee, a smoke -- whatever -- and relax about it.

* Rigging it -- It can be tempting to "home engineer" a fix that isn't quite what the manual called for, but seems like it ought to work. This is ok in an emergency -- as when you're dealing with a broken down car in the middle of nowhere and just need to get it to run long enough to get you somewhere -- but don't do it otherwise. It can be tempting, sure -- but more often than not, the "fix" ends up causing more problems than it solved. Do it the right way, "by the book."

* Refusing to ask for help -- Pride definitely goes before the fall, in politics and car repair alike. Even the best of us don't know everything; the smart among us know it's no sign of weakness to ask someone who does. Just the opposite. If you can't figure out what the manual says, or are having trouble getting something to work, there is no shame in seeking the counsel of others, be they more experienced friends, online resources -- even a professional mechanic at a car dealership, etc. (They're often quite willing to help out; it just takes your having the guts to go up and ask them.)

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