For this entire century, the factory has been telling people that they never have to change the coolant in their cars. Maybe they figured that most of them would spring a leak and get changed anyway. Long ago, Karmakanix sorted out some cooling systems do not tend to leak, and the result is that the old coolant is now clogging up their heater cores, and an occasional radiator. And we simply did not have this issue last century when coolant got changed on a regular basis. When coolant gets too old, deposits start to form, eventually resembling an egg shell coating inside the system. And if some one adds some sort of StopLeak or well water with a high mineral content, the deposits are more like concrete.
Few customers realize that there are 7 basic kinds of coolant. There are 3 kinds for European cars, and 4 different coolants for Asian cars. And the European cars take different formulations for different year ranges. For VW and Audi, the coolant formulation changed in 1996, then again in 2006. It is very important that a coolant change be done with exactly the correct coolant. We rely on Pentosin, the company who manufactures the coolant for the factory.
At Karmakanix, we keep track of the age and condition of your coolant at each service. We recommend changing the coolant when we detect that it is too weak or contaminated, hopefully before the deposits begin. Sure, modern coolant lasts longer than the old stuff, but nothing is forever. We only use the factory specified coolant, and you should know that adding anything else is asking for deposits, no matter what they tell you at the parts store. Basically, a regular coolant change will keep you from ever having to flush the cooling system. Figure on changing the coolant every three years or 40,000 miles. Did we mention that most flushes don’t remove the deposits?