Why does my thermostat keep failing?
A year ago I had a leak in the heater core and used stop leak
because it was leaking inside the driver's side floor area.
Since then, I have had to replace the thermostat three times
and now needing to a fourth time. What would cause them to
go out so quickly? I have the lifetime warranty and only use
the orange coolant.
Possibly due to the use of the stop leak. Not only does it plug the hole in the heater core, but if left in the system will also cause thermostats to stick. Stop leak is a temporary repair to get you by until you get home to a regular mechanic. I would replace the heater core and flush the system with 50/50 mix of distilled water and distilled white vinegar. After it runs thtough the system at full operating temperature,let it cool down and then drain the radiator and flush the system again with just distilled water(water from tap has minerals that can plug the system). Drain and refill with your recomended coolant. I personally switched to autozone universal coolant and i dont get all the sludge i had with the orange stuff. Autozone makes a fail safe thermostat that sticks open if the car overheats which might save an engine. Dont forget to bleed the system if the car is equipped with air bleeders or it will overheat. Hope this helps.
Exactly, stop leak products often cause more problems than they fix!! As David said they plug up everything!! A good coolant flush is needed and a new heater core! Hope that helps! Jim