I have been advised by an experienced "car guy" to change the thermostat on my 94K miles 2005 Toyota Matrix, although everything seems to be fine at the moment. Everybody else is telling me to leave it be until there are problems. It it were easy I would just do it, but it seems like it is going to be a rather involved process, or I would have to pay someone to do it. What do you think I should do?
This may fall into the "Automotive Urban Legends" category. Many years ago it was advised to change your coolant every year. The coolant broke down and the corrosion inhibiters failed to control rust. Pieces of rust would clog radiators, heater coils and thermostats. With the advent of long life antifreeze service intervals have been extended. If your 2005 has never had the cooling system serviced I would suggest new hoses, a system flush, new coolant. If the coolant looks muddy or rusty I would consider changing the thermostat. If changing the heater hoses is beyond the budget (some of these are vehicle specific and can get costly) do the upper and lower radiator hoses at the least.
If it ain't broke don't fix it.Thermostats are generally easy to remove and test with hot water and a thermometer to ascertain that they open at correct temp.Workshop manual shows how.When reassembling ensure all mating surfaces are clean;use new gasket and check for corrosion of housing as they are sacrificial