Air conditioning makes the cooling system work harder
The two systems share the front of the vehicle, and most drivers have no idea they interact.
The air conditioning condenser sits ahead of the radiator. When the air conditioning is running, it is dumping heat into the air that then passes through the radiator, which means the radiator is being fed warmer air than it would otherwise get. At the same time the engine is working slightly harder to drive the compressor.
The practical consequence is familiar even if the reason is not: temperature gauges climb in slow traffic on a hot day with the air conditioning on, and settle once it is switched off or the vehicle gets moving. On a healthy system that is a margin being used. On a marginal one it is the point where the margin runs out.
If your vehicle does that, it is worth having checked rather than managed by switching the air conditioning off.
What a service covers
The radiator, pressure cap, thermostat, hoses, water pump, fan and the coolant itself.
Two findings are common and easy to miss. The first is a radiator or condenser blocked externally with debris, which cannot shed heat however good the rest of the system is. The second is a pressure cap that no longer holds pressure, which lowers the boiling point of the coolant and costs very little to replace.
Coolant is a fluid with a service life
Coolant protects against freezing and against corrosion, and the corrosion additives deplete over time whether the vehicle is driven or parked.
Depleted coolant looks like new coolant. What it does is allow the radiator, heater core and water pump to corrode internally, which turns a fluid change deferred long enough into a radiator.
Towing
A loaded vehicle on a long climb produces heat continuously, and that is the condition that finds a cooling system working below par. If your vehicle tows, have it checked before the season rather than during it. See scheduled maintenance.
About this store
The Boise store runs sixteen services, managed by Tyrel Perkins, open Monday to Friday, 8:00 AM to 5:00 PM. Twin Falls and the Idaho Falls consumer store also offer this service.
See the national cooling system page for all 33 locations.