1999 GMC Safari Owner's Manual - Page 272

yellowblue What to Use Refer to the Maintenance Schedule to determine what kind of lubricant to use. See "Recommended Fluids and Lubricants" in the Index. Radiator Pressure Cap NOTICE: Your radiator cap is a 15 psi (105 kPa) pressure-type cap and must be tightly installed to prevent coolant loss and possible engine damage from overheating. Be sure the arrows on the cap line up with the overflow tube on the radiator filler neck. When you replace your radiator pressure cap, a GM cap is recommended. 6-26