Q: Antifreeze problem

If you are having to periodically add antifreeze to the cooling system, there could be either an internal or external leak. That would include a "leak" through a faulty radiator pressure cap, which fault in the cap, if the fault exists, could be at least a part cause of the engine overheating. Coolant leaks are investigated in a cooling system leak diagnostic and estimated and repaired as required. Without examining your car’s cooling system, I cannot inform you as to whether the overheating (caused by, say, a stuck closed thermostat) is merely coincidental to the leak, is a cause of the leak or, even, in the case of a defective radiator pressure cap is a cause and a consequence of the leak. That is, in the latter scenario, if a faulty radiator pressure cap opens prematurely and doesn’t maintain adequate pressure on the cooling system, coolant will flow out from the cooling system into the overflow reservoir as a "leak", possibly even overflowing the reservoir and thereby eventually causing the car to overheat as the coolant level gets ever lower. At any rate, at the same time that a leak diagnostic, and pressure test is performed, all the usual causes of cooling system overheating would be diagnosed by the responding certified mechanic in an overheating diagnostic. Please let us know if you have additional concerns and we hope to resolve this for you.