Maintaining Car Cooling Systems

It was not long ago that we walked into a retailer and bought a gallon Prestone, Peak or Zerex with total confidence that it would be just fine for use in our cars.

Most cars today require only an occasional check to make sure all is well.

Have you noticed how many variations of Prestone, Peak and Zerex there are these days? In addition to the familiar green antifreeze concentrates, there are orange and yellow "extended life" products, and there are also a number of "ready fill" prediluted products. The prediluted products are convenient because most of us are needing to top-off our cooling systems, not change the fluid, when we buy a gallon. These products are ready to use and save time while insuring a proper mix of antifreeze and water.

In most cases, the cooling system needs to be checked visually about once a month to be sure that the coolant level in the overflow bottle is adequate. It is not necessary to open the bottle or radiator to do this! If it is low, add enough of the correct coolant type to bring it to the "full" line. Here is a general guide as to what is the "correct" type for you car, but check your owner's manual to be sure. By the way, it is best not to stray from the type of coolant that came in the car from the factory.

General Applications:

Check your user's manual!

Conventional "green" coolants (i.e. Prestone II, Peak, Zerex): Use in GM vehicles model year 1995 and older except Saturn; Chrysler Corp. except Intrepid/Concorde/LHS after 1998, Ford before 2002 except Mercury Cougar 1999 and newer. Most Korean cars.

Carboxylate "orange" coolants  (I.e. Dex-Cool) GM 1996 and newer, Saturn 1997 and newer. German cars after 1995

Hybrid coolants, some are orange some are yellow such as Ford / Zerex G-05, Peak Extended Life: Ford 2003 and newer; Mercury Cougar after 1999; Saturn 1996 and older. Most Japanese brands. Most German cars before 1995

Service Periods:

GM 1996 and newer, Ford 2003 and newer, most German cars 1996 and newer, some Chrysler and Some Japanese (see owner's manual) can operate up to 5 years or 100,000 to 150,000 miles between coolant changes.

All others: Change coolant every 2 to 3 years.

Change coolant if coolants have been mixed, or if any discoloration or problems are suspected. Its cheap insurance!

Compared to water. Higher vales transfer heat more poorly, while vales of less than 1.0 would transfer heat more efficiently. Ethylene glycol has a specific heat of 2.78, and propylene glycol has a specific heat of 2.73. At 50% water and 50% antifreeze, the specific heat of engine coolant is much closer to that of water.

This illustrates the necessity of mixing water and antifreeze to make engine coolant!

In very warm areas some operators use water with corrosion inhibitors. The use of water is successful because although the boiling point is lower than with glycol-based antifreezes, the heat transfer is better, and the operating temperature of the engine often decreases enough to avoid boil-over problems.