Secret No. 3: You don't need a valve job.
Cheap mechanics aren't always the bargain they appear to be. Hutt recalls one customer who began to experience serious backfires not long after an oil change by a low-cost mobile mechanic. The same mechanic then diagnosed "a valve problem" and declared it outside his skill set. Fortunately, a reputable tech discovered the oil reservoir had been overfilled by about two quarts and was floating the lifters. "A disreputable guy would have gotten that apart, found nothing, sent the cylinder heads out to be reworked, probably put a set of lifters in it and handed the customer a $1,500 to $1,800 repair bill," Hutt says. And ironically, he would probably think he had somehow fixed the problem, because he would have had to change the oil in the process.