It’s generally expected that a mechanic will do whatever repairs you need, provided they have the tools, time, and capability. But once in a while, your friendly auto tech might refuse a job.
A Toyota Camry owner pulled into a Florida repair shop asking for a new timing chain, a new oil pump, new water pump, and the engine resealed from top to bottom. The mechanic scanned the car, test drove it, and turned the work down.