How to Replace a Radiator Hose Clamp

Every 3 to 5 years, radiator hose clamps and radiator hoses should be replaced so that the engine is in proper working order. With age and use they can become brittle, swollen, or corroded. The radiator can only cool the car if the internal pressure stays high. If the hose clamps become faulty or are improperly installed, the internal engine pressure will drop, and the car will overheat. Be sure you are careful when installing a new radiator hose clamp. Luckily, this is an easy task which should only take about half an hour.

Step 1 – Cool the Engine

Due to the elevated pressures of the cooling system, severe burns can occur if the radiator is messed with before the car can adequately cool. Allow the engine to sit for 1 hour before working on the radiator. Remove the petcock fitting on the bottom of the coolant tank and drain all coolant out of the engine into a drip pan. Once removed, return the petcock fitting. Coolant is highly poisonous and environmentally hazardous, so be sure to dispose of it properly.

Step 2 – The Hoses

Before removing the clamps or hoses, measure their length and consult the owner’s manual for the diameter. Do not eyeball or guess the diameter, as many vehicles can use different sizes, or sometimes multiple sizes, that only differ by an eighth of an inch.

Step 3 – The Clamps

Replacing the clamps is necessary even if they look okay. Extreme pressure can weaken the clamps with age. If the clamp breaks, the pressure within the engine can drop rapidly and cause overheating. Remove the clamps by unscrewing the screw or using pliers, depending on the type of clamp used. Once removed, carefully use the knife to slice the end of the hose lengthwise 1 inch. Do not twist the hose to remove it from the heater core. Wiggle the hose off the fitting. Do not just pull the hose off, as this can cause the hose to snap off, and the entire heater core will need to be replaced.

Step 4 – Replacing

Use the green scrubber and a rag to gently scrape any debris off the fittings. Do not use water; merely blow the debris off. Apply a small amount of gasket sealant to all sides of the fittings. Do not apply large amounts or the sealer may clog the hose. Securely place the new hose onto the fitting. Do not apply additional gasket sealant. Too much sealer can create issues with the fit. Secure the new clamps with either pliers or a screwdriver, depending on the variety. The fitting should be extremely snug but not damaging to the hoses. Refill the car with coolant.

Step 5 – Checking

Use a radiator pressure tester to be sure the hose fittings and clamps are holding. If any leakage or drips occur, turn off the vehicle and allow it to cool for 15 minutes. Wipe away the coolant, tighten the clamps, and test again.