Antifreeze - Red, Green or Universal, That is the Question!

Classic Car Radiator
Giant Classic Car Radiator. Photo by Mark Gittelman

Every spring we work on getting our classics ready for the road. For us road ready means our antifreeze is up to the challenges of summer driving. This year our master maintenance log shows the Morris Minor and our beloved Jaguar E-type British sports car both need a coolant system flush.

Join us as we uncover the facts about universal antifreeze. We'll also share some tips from our mechanic about what's required to make the switch.

Shopping for Antifreeze

We ventured off to the auto parts store to buy the conventional ethylene glycol green coolant we've always used. Once inside the popular chain store we started browsing through the antifreeze section. This year we noticed something different in regards to the varieties of engine coolant to choose from.

Various well-recognized brands are now offering a universal type of antifreeze. The labeling proudly states, these fluids are good for any year, make and model car. So back to the house we go to do a "Google" search for the new coolant option. We learned that these universal coolants use a unique OAT-based corrosion package.

They contain proprietary organic acids such as carboxylate to provide broad spectrum protection. After consulting with our local car clubs and mechanic we found they've been using the newer technology without incident. In addition, we uncovered compelling pro environmental arguments that convinced us to give the universal coolant a try.

However, the following conditions are recommended by our trusted and certified mechanic. You must completely flush out the old coolant. Next you should make a commitment to continue the normal 3 years/30,000 mile scheduled maintenance. And remember to periodically test the coolant's pH level with a dip strip.

Finally, if you live in a cold climate, make sure you test the freeze point.

Breaking the Old Antifreeze Habit

Typically, we always stick with the manufacturers recommended fluids, but are intrigued by only needing one type of coolant on hand for both our newer and older cars. Our classic cars use an inorganic acid coolant and are bright green in color. You'll find these types of ethylene glycol based engine coolants in a wide variety of classic cars.

If you own a 1976 Cadillac Coupe Deville or a 1957 Chevrolet Nomad two door Station wagon this is the type of fluid you'll see. Maintenance intervals vary between manufacturers, but are generally recommended every 3 years or 30,000 miles. It's important to follow these maintenance guidelines as the PH level of the antifreeze can change over time and become acidic. Regular fluid changes can prevent damage to the cooling systems most vulnerable component, the radiator.

Keep the Extended Life Antifreeze in Newer Cars

Just because we bought the universal style coolant for the classics doesn't mean we're draining the extended life coolant from our newer vehicles. In fact, our 2011 Jaguar XJ-Series uses the new organic acid technology, or OAT. This antifreeze is identified by its bright orange color.

The promise of the OAT is stable, long-life corrosion protection.

This can be as much as 10 years/100,000 miles instead of the 3 years/50,000 miles that are typical with the old green stuff. With this kind of protection it would seem wasteful to drain it out prior to its recommended service interval. The extended life antifreeze isn't recommended for your older classic cars, because it can eat away at older style radiators with lead based solder. Visit the repair section for more time-saving and valuable classic car maintenance tips.

Edited by: Mark Gittelman