Antifreeze additive

There are several additives on the market here's one www.amsoil.com/storefront/rdcb.aspx and here's another www.redlineoil.com/product.aspx?pid=74&pcid=10 and here's an article on Supplemental Coolant Additives www.imcool.com/articles/antifreeze-coolant/SCA-Part1.php.

Ford diesels (among others) use SCA's as an additive, but GM DuraMax diesels do not. Baldwin coolant bypass filters are sold containing SCA's in pellet form for Ford diesels and others (www.baldwinfilter.com/productscoolantcontrolledrelease.html) and without for others. Here's a link to a Ford product www.dieselfiltersonline.com/Vc-8-Motorcraft-Diesel-Cooling-System-Additive-Vc-8.aspx These additives are designed to break the surface tension of water (a wetting agent) and provide additional corrosion prevention. Do not mix SCA's with GM Dex-cool that your truck came with from the factory.

Use a good quality coolant including GM's OEM Dex-cool, that contains the SCA (Fully Formulated ASTM Specification ASTM D-6210) as noted on the label. I use Amsoil coolant but there are others, and either test it annually with a test kit (www.baldwinfilter.com/productscoolantfleetstrip.html), or send a sample to a lab for analysis, or just have the system flushed and refilled every three years. There is no need for additives in the DuraMax.