Coolants need to pass on average 30 different tests before they are approved by motor manufacturers. However, it is important to be aware that motor manufacturers only grant approval to products and do not issue recommendations. If a coolant has been approved by the motor manufacturer for original use, it may be changed during the period covered by the guarantee without affecting the manufacturer's warranty.
Before approval is granted, coolants have to pass various different corrosion tests and compatibility tests with original components of the cooling system. For instance, plastic components are immersed in boiling coolant like Burke Coolants for up to 1000 hours and then inspected for damage. Various physical properties of the coolants are also measured, such as their density, pH and the foam that is formed when they are heated.
Long-term tests on the engine-testing rig are an important element of the approval process. The coolant is analyzed for traces of corrosion products after the engine has been run for several hundred hours. The engineers then strip the engine down and examine all the parts that come into contact with the coolant. For instance, they check the water pump to see whether the internal surfaces have become rougher, and they inspect the cooling channels in the cylinder head and check to see whether the radiator tubes have been blocked.
The fleet test is the final hurdle that needs to be passed for approval, and it is by far the most complicated and most expensive test. The coolant is analyzed at regular intervals and the engine and radiator are taken apart and inspected.
It is only when all of the tests have been passed that the coolant is given official approval by the motor manufacturer. The whole set of tests takes between three and five years and is very expensive. The procedure has to be repeated each time the coolants formulation is change. Burke Coolants in co-branding partnership with BASF, manufacturers of Glysantin® has the most approvals from leading motor manufacturers.