Car Care & Valeting
Coolant and Antifreeze Technology
Comma explains why accurate application data is essential when selecting antifreeze and coolants.
As with engine oils, many modern vehicles now require manufacturer specific antifreeze and coolants – so, what’s behind this trend and why is it so important to select the correct product?
As ever, it’s all down to the vehicle manufacturers. They invest untold millions in new technologies that have given us smaller, more powerful and fuel efficient engines with reduced emissions. Since these engines have to deal with higher operating temperatures and faster fluid flow, their cooling systems are considerably more complex and, relative to engine size, bigger than they once were; some include multiple radiators, and they all incorporate components made from many different materials. In fact, engine coolant comes into contact with 200 components that are commonly used in different engine and cooling systems.
The need to protect these components from corrosion, rust, erosion and pitting is the key reason behind the growth of vehicle manufacturer-approved antifreeze and coolants. Product selection would be easy if every manufacturer developed their engines and cooling systems in the same way with the same materials. However, this is far from being the case. They take different approaches and have different ideas as to which corrosion inhibitors offer the best solutions for their systems.
This has necessitated the development of three non-interchangeable coolant technologies relevant to contemporary vehicles, highlighting the need for service technicians to familiarise themselves with these and their correct application. They represent an important step change from generic ‘commodity’ antifreeze, and are identified as either ‘Hybrid’ (Silicate based), ‘OAT’ (Organic Additive Technology) or ‘SI-OAT’ (Silicated Organic AdditiveTechnology).
The critical differences between them are evident in the ways they operate. Silicate based inhibitors physically deposit on engine surfaces. They are not very selective, which means they cover all surfaces regardless of what they are made of, and when compared to OAT based inhibitors, they form a thick protective layer. On the other hand, OAT based inhibitors form chemical bonds with vulnerable surfaces, making the protective layer extremely stable. They are very selective, targeting only the areas that need protection, and forming much thinner layers when compared to their silicate based counterparts. Essentially, both do similar jobs, but in different ways.
SI-OAT seeks to take the advantages of both types and combine them in a single technology, but it would be completely wrong to conclude that SI-OAT is just the other two mixed together. It is made by an entirely different manufacturing process, specially developed by chemicals giant BASF for all VAG Group vehicles from 2005 onwards.
It is crucial to comprehend that all three products represent a distinct type of technology covering a different set of vehicle manufacturer specifications. They are not always interchangeable, and should never be mixed or substituted one for another. This means that accurate applications are vital, because the wrong product can quickly damage the cooling system.
Comma’s application data ensures that identification of the right coolant for all vehicle manufacturers’ engine types and models is simplified. It is available via the online VRN look-up facility on the home page at www.commaoil.com and in the printed Comma Workshop Application Guide. For your complete trust and confidence, every recommendation is covered by a 100% Quality & Performance Guarantee.