Flushing out the Facts on Radiator Flushes

Dear Tracy,

I have not been a car owner for very long and am trying to learn what auto service is needed and what I can skip to save some cash. I have heard that getting a radiator flush should be part of car maintenance. Can you please tell me if a radiator flush is necessary, what it entails, and how often – if ever – my car needs to have one?

Rob L.

Dear Rob,

A radiator flush should definitely be a part of your regular vehicle maintenance. The function of your car’s radiator is to provide cooling to the engine by taking away the heat produced during normal engine operation. Your car’s cooling system does this by circulating a coolant through the engine block, which absorbs the heat and takes it to the radiator where it dissipates into the atmosphere. This prevents overheating which can otherwise damage the engine.

With the accumulation of miles, solid deposits can form inside your car’s radiator system, causing blockages that make the circulation of the coolant much less efficient. This causes the vehicle to run hotter and damage occurs due to excessive heat build-up. This problem can be avoided by periodically performing a radiator flush. A radiator flush involves draining the original coolant from the radiator and replacing it with a special coolant mixture that cleans the system. This mixture circulates through the vehicle’s cooling system, dissolving and removing any solid build-up inside the radiator channels. This mixture is then drained and replaced with a standard mix of coolant and water.

The radiator flush process can take a few hours because the vehicle’s existing coolant needs to have time to cool down completely before it can be safely drained. Your auto technician will then need to run the engine with the cleaning mixture until it reaches normal driving temperature. At this point, the vehicle’s heating system needs to run at its highest setting for a while. Then, after the cleaning mixture temperature drops, it needs to be drained and replaced with the standard coolant and water solution.

Vehicle manufacturers usually include a recommended schedule for radiator flushing. Schedules are based on engine specifications and the type of coolant that is used. The typical frequency is at least once every 2 years or 30,000 miles. In areas where winters are especially harsh or summers are extreme, it is recommended that you schedule a radiator flush at the start of each season.