Antifreeze question

[dodj]

How often do you change the antifreeze in your classic car? It would take many years for it to reach the recommended change interval based on mileage. Do you change it anyways base on time interval?

My time frame is 5 years max. on all my vehicles. BUT...for the Challenger....I never seem to go more than two years without doing something to the engine that involves draining antifreeze. And I always put fresh back in...so I guess I change the antifreeze in the Challenger every two years.

[jimynick]

Back in the day, it wouldn't be unusual to put 60-70,000 miles on a batch of antifreeze, so I wouldn't get my panties in too tight a knot at 10-20,000 these days. The new stuff is better formulated now and would anybody here actually put that kind of mileage on their cars? I've put about 5-6000 on mine since 2016 and I drive it; the Sunday-go -to-meeting people probably don't put 1000 on a year and theoretically, they'll never need to change their coolant. Check the PH and change accordingly, not by the calendar. Just my 

[cudabob496]

Antifreeze is also corrosion inhibitor, and that may be more the reason to
change more ofter. You can also inhibit corrosion by having a battery disconnect
to open, when the car is sitting in the garage, otherwise you will still have a 12 VDC
potential across your engine.  And there is even more of a potential for corrosion
if you have disimilar metals, like aluminum and iron. And you can separately add
additional corrosion inhibitor, so as not to change your coolant antifreeze as often.

[YellowThumper]

Antifreeze is also corrosion inhibitor, and that may be more the reason to
change more ofter. You can also inhibit corrosion by having a battery disconnect
to open, when the car is sitting in the garage, otherwise you will still have a 12 VDC
potential across your engine.  And there is even more of a potential for corrosion
if you have disimilar metals, like aluminum and iron. And you can separately add
additional corrosion inhibitor, so as not to change your coolant antifreeze as often.

Exactly why I keep mine at the 50/50 ratio. Corrosion and lubrication. To me it has been best because the durations of downtime outweigh issues of potential overheating.