Dear Tom and Ray:

I was told that a good way to extend the life of a car is to periodically replace the radiator. Is this an urban myth, or a useful suggestion? If it is a helpful suggestion, does it pertain to all makes, models and years of cars? How often should this be done? And what is the purpose of doing this? Thank you. -- Pattsi

RAY: Trust us, Pattsi. If there was any validity to this theory, we'd already be advertising an "oil, filter and radiator change" special at the garage.

TOM: The radiator is not something that should be replaced as a matter of routine maintenance. It IS, however, something that might require attention from time to time.

RAY: All coolants have rust inhibitors in them. When those rust inhibitors lose their effectiveness, the inside of the radiator can start to corrode.

TOM: You want to avoid that, because rust particles can travel through the engine and clog up tiny cooling passages that are vital to keeping the engine cool.

RAY: A number of cars are now coming with "lifetime" organic coolants that never need to be drained and replaced. But there are lots of cars on the road that still use traditional coolant, and that should be drained and replaced every couple of years to remove any crud and update the rust inhibitors.

TOM: And no matter what kind of coolant your car uses, if you live in a part of the country where they salt the roads in the winter, you should also have your mechanic check the integrity of the OUTSIDE of your radiator, starting in year four or five of the car's life. You want to make sure that the metal fins are not rotted, because that can cause inadequate cooling. And that will definitely cause you to cook your engine over time.

RAY: So check your owner's manual, Pattsi. If it suggests that you drain and replace the coolant, do that. Then, if you live in the rusty portion of the planet, have your mechanic inspect the outside of the radiator and replace it when he sees signs of corrosion. But there's no need to replace it proactively before then.