GM 3521237 Hose

Inspect all upper and lower radiator hoses as well as heater hoses for signs of decay, leaks or loose hose clamps at every 15,000 miles (24,000 km) or as part of the seasonal maintenance in early spring or late autumn to early winter due to weakened hoses that may cause sudden failures. Be sure that the engine and cooling system are cold before looking at it. Look to see if there are any cracks, rotting or collapsing of the hoses, if so replace them with new ones. Look along the length of the hose for any weak spots where they might be swollen; these indicate that it is time to change them out. When you are replacing the hoses, be careful not to damage the necks as you take them off. If a hose will not come off easily, do not use sharp tools; rather make an accurate crosswise cut through its stuck portion and lift the hose away from it. Clean up connections on all hoses inspect and replace clamps as necessary. To fit slide clamps onto your hose ends dip these in clean engine coolant, fit hose ends onto connections then secure clamps at least four inches from each end of the hose. Close drains, refill cooling system with a suitable coolant mixture and check for leaks using a pressure tester or by running engine to normal operating temperature and inspecting for leaks around hose fittings and connections.