Why does the heater hose on my 2007 Pontiac Grand Prix 3.8 liter keep busting?
I have never heard of such a thing. Maybe the radiator is clogged?
Or the heater core?
Excessive pressure bursting hoses or forcing the coolant out through the cap can be caused by a blown cylinder head gasket or cracked cylinder head. In this situation the cooling system is pressurized by being exposed to a cylinder, this means that every time the engine fires it pushes gases into the cooling system. A clue to this is if the car blows bubbles in the radiator expansion tank, you'd be able to see these if you run it with the cap off and look in. Obviously you need to be careful when removing the radiator cap if the engine is hot. It's not unknown for this fault to rupture the radiator or the heater matrix as well as the pipes. (not all together of course, it'll usually burst the weakest component). I'm not saying that this is definitely what's wrong with your car but given the symptoms you should check it out. As well as visible bubbles in the expansion tank, if you used a cylinder compression tester then one cylinder would read low if you have this fault.
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