Countertalk: Antifreeze/Coolant Proliferation a Challenge

The proliferation of coolant/ antifreeze formulations on the market has caused a fair degree of misapplication. In some cases, this has been known to cause various degrees of damage to engine components.

Ethylene Glycol (EG) based coolant/antifreeze still makes up the lion’s share of the market–a market in which demand is declining due to lower capacity cooling systems and longer drain intervals–but there are some emerging categories even within the EG category itself.

Pushed by initiatives for “lifetime sealed systems” at the car maker level, Extended Life Products are notable additions to the EG category. These tend to have a concentrated blend of inhibitors to combat corrosion, of particular importance in aluminum block and/or cylinder head engines. These offer valuable benefits in that they address the fact that car owners seldom replace their coolant as often as they should.

Heavy duty formulations, also fortified versions of the standard EG coolants, have special low-silicate formulations for heavy duty diesel applications that allow for the use of supplemental coolant additives (SCAs) commonly used to give as much as 500,000 km of protection.

One addition to the EG forum is a direct result of an initiative by General Motors for a long life coolant. The Dex-Cool formulation uses a patented carboxylate formula with no silicates. This orange-colored antifreeze/coolant is an emerging product which will see increased popularity, as GM cars and light trucks using it require renewed coolant after 160,000 km or so.

The most recent technology to join the fray is G-05, an ethylene glycol-based coolant with an HOAT (Hybrid Organic Acid Technology) inhibitor package. It is phosphate free, fully formulated (contains nitrite) and protects against hard water deposits and corrosion. While the product is new to the aftermarket, Mercedes has apparently been using this formula for over two decades.

An HOAT coolant uses both inorganic and organic inhibitors. HOAT coolants have inorganic inhibitors that provide fast acting aluminum engine protection from boiling and erosion and organic materials that offer non-depleting, long-term protection.

Propylene Glycol (PG) formulations have also made their way into the market, boasting lower toxicity than EG-based coolants. While this is true, you still wouldn’t want to drink them, and the reality of life inside an engine for a few years means that, as with all coolants, their toxicity from contaminants picked up from the engine requires that they be disposed of properly.

One of the side effects of having PG and EG coolants on the market is the difficulty with determining the level of protection. PG coolants have a different specific gravity and can’t be properly checked with the traditional bulb-style hydrometer. Instead, they require a more sophisticated (read “more expensive”) instrument. Additionally, when EG and PG are mixed in a cooling system, it is virtually impossible to determine boil/freeze protection.

All in all, the rise in the number of coolant options provides jobbers and their customers with a variety of options and a variety of price points to take advantage of.