Hot Under the Hood
The complex additive chemistry that goes into the development of coolants has been largely underappreciated by technicians, jobbers, and counterpeople for decades.
An engine is a hot, high-pressure, corrosive environment that can easily produce temperatures of 2500 degrees Celsius; without coolant, pistons would quickly weld themselves to the cylinder.
In order for coolant to work effectively, it must be custom- tailored to the metallurgical composition of the engine. As different makes and models have different concentrations of steel, aluminum, plastic, and rubber in their engines, recommending the proper coolant is of vital importance to a vehicle’s overall performance.
Coolant is comprised of three basic yet different chemistries that usually contain an ethylene-glycol base (some use propylene glycol), giving coolant its required freezing and boil-over protection and heat transfer characteristics.
This is where the similarities stop.
The older (usually green) coolant additive formulation is referred to as Inorganic Additive Technology (or IAT), and is mainly based with silicates, phosphates, and borates. All of these inorganic additives give the coolant the corrosion- inhibiting and de-foaming compounds it needs to function properly in the engine. IATs are very robust and protective; however, they deplete quickly, allowing for only three to four years of service life (roughly 50,000-80,000 kilometres).
The search for a longer-lasting coolant (five to six years before servicing) led to the development of Organic Acid Technology (OAT), which many know best as GM’s Dex- Cool branding, in the late ’90s. OATs were different from IATs in that their chemistry was an all-liquid blend that allowed coolant to get away from a lot of problems such as drop-out with hard water and issues with solids. However, the corrosion inhibitor package isn’t fast-acting; if you have high-flow erosion, you’ll need an additive that will not only react in a reasonable time frame but can also protect under dynamic conditions.
The third family of coolant is hybrid organic acid technology formulation (or HOAT), and the idea here was to make a coolant with the best possible ingredients, and that would be faster-acting and would protect the engine for a longer time. HOATs were first developed in Europe in the early ’90s, but eventually made their way to North America as well as Asia, and are used by many of today’s OEMs including BMW, Mercedes, Volvo, Volkswagen, Ford, and Chrysler. Unlike IATs and OATs, HOAT coolants are more expensive to produce as they require more specific formulations and more additives in general.
Many manufacturers have touted the effectiveness of so- called “universal” coolants for years; a slew of them currently exist on the market that claim to meet a wide range of applications. However, “universal” is a term used loosely in this product category, as there is no one true coolant to satisfy all light vehicle makes and models.
“There are universal coolants out there, and I have a lot of problems with those,” says Dr. David Turcotte, technical director for Valvoline. “The OEMs have different chemical requirements and you really have to match their chemistry to get long-life performance and have a good result. For example, if you meet the Ford specification which requires silicate, by default you don’t meet the GM or the Toyota specifications, which forbid it. So there’s no way you could make one coolant that meets all applications.”
In fact, when you mix one chemical with another you can actually dilute each one, causing neither to work. Most universal coolants are based on some kind of OAT (something like Dex-Cool, for example), which is fine for, say, GM vehicles but not fine for everything. Different OEMs have different chemical restrictions that vary according to the specifics of a given engine (e. g., what type of gaskets are in the engine, what kind of metallurgy is in the engine, etc.).
One of the ways coolant manufacturers have dealt with this issue is by custom-tailoring their product lines to meet certain models of vehicles. Zerex recently offered a modified HOAT with a formulation specifically built for Asian vehicles. Many Asian vehicles require a special kind of HOAT that’s silicate-free and contains phosphate with organic acids.
Also, keep in mind that the difference between a coolant that meets standards and a coolant that gains the approval of OEMs is huge. An OEM approval means higher quality and higher costs. If it meets the specifications, “meet” doesn’t necessarily mean it’s OEM-approved. To get a Dex-Cool approval from GM, for example, one of the standard protocols is called the five-year vehicle test: not an accelerated or simulated five-year vehicle test, but 60 months of consecutive testing with the coolant in question, generating research and development costs that are easily in the millions.
While HOATs are more expensive than OAT and IAT coolants, keep in mind that the cost per gallon is only nickels and dimes when taking into account a longer-lasting engine and less frequent trips to the service garage. This is why it’s crucial for jobbers to supply the best possible antifreeze for your technician customers.
“Questions jobbers should be asking to satisfy their technician customers or consumer needs include, first of all, what is the application? Is the vehicle a passenger car? Is it a light-duty, medium-duty, or heavy-duty vehicle? Is the engine gas or diesel? And if the engine is diesel, does the customer use SCAs (supplemental coolant additives)?” says Gord Robertson, managing director for Honeywell Consumer Products Group Canada under its Prestone brand. “The older, less expensive ‘green’ antifreeze is not recommended when servicing vehicles today, because it only lasts two years or 40,000 km, compared to extended-life coolant that lasts up to five years or 250,000 km.”
“It pays to ask what [the technician] is looking for. ‘What’s the application you’re looking for? What’s the specific vehicle?’ A lot of guys will call in and ask for the cheapest stuff they can find, which is not necessarily the best application for the vehicle they’re working on,” says Dennis Favaro, product manager for Valvoline Canada. “They should try and make sure they’re providing a quality product that meets the specifications of the OEMs.”
“If the prospect is a fleet operator, then knowing the mix of the fleet in terms of year, make and model is important, because a complete drain and refill is not always warranted when a unit is in for routine preventative maintenance,” says Amanda Li, marketing manager with Shell Canada Ltd. “If the customer is in the retail channel supporting the passenger car market, then inquire about an inventory strategy to minimize stock keeping units. This can displace several application-specific products, simplify the selection process for the consumer and maximize the utility of retail space.”
Controversy Over Dex-Cool
Over the last few years Dex-Cool has caused controversy in the coolant market, with litigation connecting it with intake manifold gasket failures in GM’s 3.1L and 3.4L and with other failures in 3.8L and 4.3L engines for GM-model vehicles made between 1995 and 2003. While class action lawsuits were registered in Canada (as well as several U. S. states) to address some of these claims, the first jurisdiction to reach a decision was in Missouri, where a settlement was announced in December 2007.
The lawsuit also led to rumours that mixing Dex-Cool with a standard green (non-OAT) coolant caused a chemical reaction that produced sludge in the cooling systems. According to the Dex-Cool manufacturer, however, “mixing a ‘green’ [non-OAT] coolant with Dex-Cool reduces the batch’s change interval to two years or 30,000 miles, but will otherwise cause no damage to the engine.”
In March 2008, GM agreed to compensate complainants in the remaining 49 states. There has been no word as of yet on whether Canadian complainants will be c
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