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first, don't wait for it to overheat before you fix a leak problem. if you have more than 150,000 miles on the car or the hoses, or the hoses aren't of good quality, go ahead and change all of them out. like starting with a clean slate. if you waited long enough for the fans to start coming on before you checked the temp of the hoses then you may have a bad thermostat. they're cheap anyway so if you do the hoses you should do that too. but if you do all that and find that the heater core is leaking... those stink to replace in most cases.

 

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