I have a 2006 Dodge Stratus and my overflow is either bubbling or boiling but my engine doesn't over heat until I have drove for about 30 minutes or so. I just had my alternator and tensioner pulley replaced. What could be wrong
Generally speaking - the Alternator and Tensioner Pulley should not have any relation to the cooling system, unless somehow the water pump is belt driven and the mechanic put the belts on incorrectly, but I don't think this is the case.
Is there a rubber hose you can carefully reach with your hand going from the radiator to the engine / coolant housing? Is that hose super inflated / tight when you squeeze it (when the issue is happening).
More likely you have something like a stuck thermostat.
Many things can cause a car to overheat, however if you've just had some work done I would start the search there. Check the serpentine belt routing to make sure it was put on correctly. On some cars the belt will fit in 2 or 3 different ways, but only 1 way is correct. In this case the water pump could be turning backwards, which could certainly cause an engine to overheat.