1999 Chevy Tahoe

Well, A thermostat replacement is a fairly simple procedure, but it depends who you take it to and what they charge as far as how much it will cost. It is under an hour of labor so it should be the mechanic's hourly rate or less plus the cost of any parts needed. Should be just the replacement thermostat and a gasket. If you have a basic set of hand tools including metric sockets, wrenches, etc.) And a general knowledge of mechanics, you can do this procedure yourself. Let me know if you think you might want to tackle it.