Maybe you’ve taken your car in for some recent service and the mechanic let you know you needed a cooling system flush. Or perhaps you noticed your vehicle was a little low on coolant, and when you went to top it off you noticed some gunk floating in the overflow tank or radiator. Or, my personal favorite, you go to turn the heat on and you only get cold air even after your vehicle is well warmed up. These all are good indications that it may indeed by time for a radiator flush, or more accurately a cooling system flush. But how did all the gunk get into your radia- tor, the cap has been on tight for years, so there shouldn’t be any way for contamination to get in there—right? If all the gunk that clogged up your heater core didn’t come from outside your engine, then it must be coming from your engine. Is there something wrong, or is something about to break? Before you go pulling the engine out of your car in search of bigger problems, let’s figure out why your cooling system needs to be flushed even though it is a closed system. Antifreeze, it turns out, is more than just green water that doesn’t mind the cold weather. The main ingredient in Antifreeze is ethylene glycol and it is the chemical that allows antifreeze to stay liquid even in extremely cold temperatures. Also included in antifreeze is a certain mix of lubri- cants and corrosion inhibitors. Usually, water and steel don’t mix well, and the steel will rust quickly.
The corrosion inhibitors in the antifreeze slow this process but never stop it completely. Also, these corrosion inhibitors have a finite life span in your cooling sys- tem and after time will start to allow more rapid corrosion to occur. The biggest cause for increased corrosion in your vehicle’s cooling system is improperly mixed antifreeze. Many off-the-shelf antifreeze options require mixing with water before they are added to your vehicle. If you use water from your tap to mix with your antifreeze, you are adding a whole new spectrum of chemicals to your coolant, many of which can be harmful to your vehicle. Even fil- tered tap water has minerals dis- solved in it, especially if you have “hard” water, and many areas have high levels of iron or other metals in the water. Also, chlorine is the most common chemical found in tap water used to kill bac- teria and make sure the water is safe to drink. Chlorine is also a very strong corrosive agent, and if added to your vehicle’s cooling system can greatly increase corrosion. Steel isn’t your only concern for corrosion particles in your cooling system. Aluminum, copper and brass also can corrode, releasing particles, and the rubber hoses and gasket can deteriorate over time adding to your cooling system gunk. So now that you’re worried about what may be lurking in your radiator, let’s look at how to flush your cooling system. First, go to your favorite auto parts store and
What is the Best Way to
Flush a Radiator?