I recently purchased a new 2006 Elantra GLS, and have a question regarding engine coolant and anti-freeze. I've been a firm believer in using the low-silicate, low-pH, phosphate-free ethylene glycol coolants, such as the Mercedes-Benz OEM coolant, in all of my cars. I have observed engine tear downs of engines using the old green-colored Inorganic Acid Technology (IAT) coolants vs. the Hybrid Organic Acid Technology (HOAT) coolants, such as the M-B coolant, and the difference was very apparent. The old green coolant etches and evenutally "eats away" aluminum parts in an engine and cooling system.
There are three basic technologies in ethylene glycol coolant: 1). The old green-colored type that we're all familiar with using the Inorganic Acid Technology (IAT), 2). The HOAT-technology based coolant such as the Mercedes-Benz coolant which is actually manufactured for M-B by Valvoline. This is Zerex G-05 coolant by Valvoline, and 3). the Organic Acid Technology (OAT) coolant, such as DexCool by GM, and available from other sources as well, including Peak, Prestone, and Valvoline.
OAT coolants are not only phosphate-free, but also silicate-free, and low pH.
Now (and, Hyundaitech if your reading, please add your thoughts to this discussion), here's my question . . .
Since Hyundai does not sell its own branded coolant like Honda, M-B, etc. do, what is the factory specification of the coolant supplied in current Hyundai vehicles? The Owner's Manual for my 2006 Elantra simply states to use an ethylene glycol-based coolant - period. Nothing about the actual formulation. I do know the original coolant supplied was green in color, thus it must be the old-standard IAT technology-based coolant. I checked with my local Hyundai dealer, and the Service Manager said: "We go over to NAPA and buy their standard coolant for all applications." Interestingly, he had never heard of the 3 types of coolant technologies available. Nor, does he use de-mineralized water or distilled water, as I have always done since the late '60s.
According to many of the coolant manufacturers' websites, they imply that the OAT coolant, specified by Honda, is best for all Asian cars. GM's DexCool is OAT-based, as mentioned previously, and the only difference between it and any other OAT-based coolant, such as Honda's, is the color. However, OAT-based coolant is NOT compatible with IAT-based or HOAT-based coolant, so you have to do a complete and thorough flush, which is almost impossible in the real world by the D-I-Y'er (Do-It-Yourself). On the other hand, IAT-based coolant and HOAT-based coolant are compatible.
As I previously stated, I've used the HOAT-based coolants for a number of years, and have never experienced a coolant-related failure, and from recently replacing a water pump in my SAAB, the aluminum casting looked brand new without any etching of the aluminum. But, should I consider the OAT-based coolant for the 2006 Elantra, or just stick with what I've used in the past? OR, am I being too technical and obsessive, and just use the approach of the Hyundai Service Manager and just use "any old coolant?" BTW . . . I typically change coolant every 2 years, which is also the Hyundai recommend maintenance spec interval on the Elantra.
Thanks for listening!
Don