An important first step in radiator maintenance is regular cleaning of the outside when you drive on snow-covered roads. The salt and calcium chloride used to melt ice and snow will attack the thin metal fins on radiators, just as it attacks the rest of the truck chassis.
“Flush road salt off,” Sholly says. “The longer you leave it on, the more cores we get to replace.”
Mascuch says it’s best to flush off the stuff by the next day, if you can. Don’t just use a garden hose. Use a pressure washing process that produces hot water and controlled pressure, like what’s available at many truckstops. (Too much pressure can bend the thin metal fins.) Open the hood and go in between the charge air cooler and radiator to gain access to the front of the radiator.
“Road salt and sludge deteriorate the fins,” Mascuch says. “The temperature will go up first as the fins get corroded off. The A/C may stop performing well. Eventually, the pressure will go up and the radiator will start leaking.”
Salt corrosion also “kills the bolts that hold the tanks on,” says Mascuch. There may be 20 or more bolts holding them at top and bottom. When a repair becomes necessary, it helps if all the bolts come out easily. If they are corroded, they’ll break off, making the job much more difficult and expensive.
Even non-corrosive dust and dirt should be flushed off before it accumulates and interferes with heat flow. You should also look at the fins every few months. Where they are bent, straighten them to allow more airflow. There is a special tool called a fin comb that may help.
You can also check that your radiator mounting bolts remain tight. Look at any rubber mounting bushings used and replace them if they have been crushed by vibration and no longer keep the radiator snugly mounted. Still Mascuch says most radiator failures don’t happen because of the mounting system, but because of corrosion.
The next step is to maintain your antifreeze.
“Mixing antifreeze is a problem,” Sholly says. “You just can’t mix the different types. Corrosion often occurs from the inside out. This happens because of neglect of the antifreeze. Take care of the coolant!”
There are two ways of doing this. You can use ELC (“Extended Life Coolant”) and add only ELC when you have leakage or evaporation, plus adding a bottle of extender in the middle of each change cycle. Or you can use more traditional methods.
The best of the traditional methods is the use of only Fully-Formulated TMC RP-329 Type A coolant – you’ll see this designation on the jug. It contains full cooling system protection. Combine this with some sort of coolant filter that provides a controlled release of SCAs, or “Supplemental Coolant Additives.” The best ones actually adjust the rate at which they add SCAs to the conditioners. The SCAs are necessary to keep system protection topped off as the anti-corrosive chemicals in the original antifreeze wear out. You need to test for SCAs at your routine maintenance intervals with this type of protection. But if you use only the Fully-Formulated coolant and the right SCA-adding filter, you’re likely not to need to add SCAs.
Either of these systems will extend coolant life to at least 600,000 miles with full protection if you follow the rules for your method. Keeping the right antifreeze with you in the truck and adding only that is the most important key to making either system work.
You also need to worry about the concentration of the coolant. Make sure to keep the antifreeze at a 50/50 concentration unless you live in an extreme northern climate, where 40/60 is allowed. The best thing is to buy and add only pre-mixed 50/50, which has de-mineralized water to help the additives work. Be careful not to allow the antifreeze concentration to get too high by repeatedly adding straight antifreeze. “Too much antifreeze is like a gel,” Sholly says.