Genuine GM Fluid 12378521 RTV Engine Sealant - 5.3 oz. Cartridge Original production sealant used in GM engine plants Recommended for all engine applications Compatible with all synthetic, synthetic blend, and minerals oils as well as coolants including DEX-COOL Special precautions: Surface should be free of residual fluids and also of detergent residues Special precautions: Joints should be closed within 20 minutes of application; final tightening should be done within one hour of application and closure