The National Truck Equipment Association has issued Upfitter Integration Bulletin #60 to advise that General Motors has developed a new engine coolant fill procedure. This procedure is for the 2003 model year full-body G-van and cutaway models (Chevrolet Express and GMC Savannah) equipped with 4-8L, 5.3L, and 6.0L Gen III V-8 engines since the cooling system no longer uses a pressurized coolant surge tank.
After a condition where engine coolant has been drained, if engine coolant is only added through the radiator neck and engine coolant overflow reservoir, the engine coolant may not flow beyond the closed thermostat on the engine at the lower radiator hose connection. Although the coolant level may appear full in the radiator neck, the system may be 3.785 to 5.678 liters (four to six quarts) low, and a major engine overheat condition may occur.
It is important to use a 50/50 mixture of Dex-Cool antifreeze and deionized water.
This procedure should be followed any time the engine coolant has been partially or fully drained from the engine. Reference GM Service Bulletin #02-06-02-008, dated September 2002, for the recommended coolant fill procedure.
Information on special service tools referenced in the GM Service Bulletin may be obtained from SPX/Kent-Moore Tools; phone 800-345-2233.