Coolant - Usage/Specifications
GMC NUMBER: 91-6B-14GROUP: 6B Engine Cooling
DATE: September, 1990
CORPORATE NUMBER: 066202
SUBJECT:
COOLANT USAGE
MODELS:
All LIGHT AND MEDIUM DUTY TRUCKS
This information supersedes information provided by GMSPO in parts and accessories bulletins IB NO. 90-55 and 90-60 and information provided in various truck service and owners manuals and should be used to determine correct coolant usage in light and medium duty truck applications.
GM coolant specification 6038-M or 1899-M (P/N 1052103) is for use in all light and medium duty trucks with gasoline or diesel engines. This coolant features a low silicate formulation and is intended only for use in engines that have cylinder heads and cylinder blocks made of cast iron.
GM coolant specification 1825-M or 6043-M (P/N 1052753) which until recently has been the recommended coolant for light and medium duty trucks has been superseded by GM coolant 6038-M or 1899-M (P/N 1052103) in cast iron truck engines. GM coolant specification 1825-M has a higher silicate formulation which is recommended for all passenger car engines with cylinder heads or cylinder blocks made of aluminum.