Consumer Repair Guide
If you want your old parts returned, ask before the work begins.
When you read your repair order, ask questions about anything you don't understand. Look for specifics in the repair order, such as: "Check for hesitation as engine warms up." If the repair order is vague, ask that it be rewritten or enhanced.
Get a written estimate. Don't be surprised if you see a hefty charge for computer diagnostics. Some problems require more diagnosis time than does the actual repair -- chasing computer wires to find a short, for example.
Understand that when you sign a work order, you agree to be responsible for the charges. Most states require shops to gain your permission before they exceed a written estimate. Be available by phone while your car is worked on to avoid delays.