MBE 900 ENGINE 2007 OPERATOR'S GUIDE Dropout Coolant Extender Inhibitor Additive for “OAT” Coolant Excessive amounts of some inhibitors in the coolant can cause a gel or crystalline deposit that reduces heat transfer and coolant flow. The deposit, called “dropout,” takes the color of the coolant when wet, but appears as a white or gray powder when dry. It can pick up solid particles in the coolant and become gritty, causing excessive wear of water pump seals and other cooling system components. The inhibitors in OAT coolant must also be maintained, but less often than traditional SCA-type coolants. A portable test is available to test the levels of OAT inhibitors in coolant.
Where this is not used, fleet testing has determined that a OAT coolant extender package should be added to the coolant at 300,000 miles (480,000 km), two (2) years, or 5,000 hours, whichever comes first. The proper maintenance dosages for all OAT coolants are listed in Table 17 , reflecting 0.6% by volume extender. This dosage should be added to the water-only and the glycol systems at the same interval. PERSONAL INJURY To avoid injury when using caustic cleaning agents, follow the chemical manufacturers usage, disposal, and safety instructions. The proper application of extender to OAT coolant will provide:
pH Control The wet gel can be removed by using a non-acid (alkali) type heavy-duty cleaner, such as Detroit Diesel Power Cool On-Line Cleaner (sodium nitrite/sodium tetraborate). Part numbers are refer to section POWER COOL ENGINE PRODUCTS. Restored inhibitor levels to prevent corrosion Cavitation protection to protect wet sleeve cylinder liners NOTE: Do not use traditional SCAs in OAT coolant, and do not use OAT extender in traditional coolant. NOTE: If the gel is allowed to dry, it is necessary to disassemble the engine and clean it with a caustic solution or physically clean individual components. All information subject to change without notice. (Rev.
04/08) 113 DDC-SVC-MAN-0040 0704 Copyright © 2008 DETROIT DIESEL CORPORATION