Testing methodology designed by the Society of Automotive Engineers (test number J2334), shows that MAGNESIUM CHLORIDE (MgCl2) is more corrosive than salt (NaCl).
Corrosion is a bigger problem than ever before because of changes in the way Highway Departments now de-ice the roads and highways. Over the past 15 years, it is estimated that the costs associated with corrosion caused by anti-icing chemicals have increased more than tenfold.
Many states and local municipalities use some sort of MgCI or CaCl to de-ice their roads. These municipal operations use MgCl because of its effectiveness versus plain rock salt:
Here is why it is having such an impact on vehicles:
Magnesium Chloride is hydrophilic – anywhere water can go, it can go. Think about all the nooks, crevices and cavities you have in your vehicle. Often these cavities do not have paint on the interior-facing panels, leaving them susceptible to corrosive actions.
Magnesium Chloride has the ability to cling to the underbody and cavity spaces of a vehicle and re-crystalize as the materials slowly dry out.
Magnesium Chloride is hydroscopic – it attracts moisture from the air (in 35% or more humidity) making it more aggressive than salt because it is active even when “dry” and long after snow is gone. As a result, it stays in a semi-solution state for extended periods of time, which multiplies their corrosiveness. (What’s the humidity like where you live?)
Over the road vehicles can be harmed even more when they drive through counties using different de-icing chemicals. Picking up all three chloride salts – calcium, magnesium and sodium – makes corrosion even worse. In terms of tractor trailers, road chemicals may affect a variety of components: structural members, suspensions, support gear, and top and bottom rails, and even reach into the sub-frame of the cab (from drivers tracking brines in on shoes).
One engineer states “MAGNESIUM CHLORIDE is basically ‘liquid rust’. It clings to everything and it attracts moisture – and it does not wash off easily”.
Do you wash the underside of your vehicle with a power washer? Unless you use some kind of neutralizing agent you could be causing more damage to the interior cavities of your vehicles; by simply pushing these brines deeper into the cavities of your vehicle.