How to inspect and replace your car’s hoses
What you can’t see, can hurt you! That’s what our engineers discovered during four years of extensive field-testing. In these tests, they identified the primary cause of coolant hose failure as an electrochemical attack on the rubber tube compound in the hose.
The phenomenon is known as electrochemical degradation, or ECD. It occurs because the hose, liquid coolant (ethylene glycol antifreeze and water), and the engine/radiator fittings form a galvanic cell or “battery.” This chemical reaction causes micro cracks in the inner hose tube, allowing the coolant to attack and weaken the hose reinforcement.
- Difficulty: Easy
- Duration: 5-10 minutes
- How often: See your owner's manual
TOOLS AND EQUIPMENT
TO INSPECT, REMOVE AND INSTALL A COOLANT HOSE, YOU WILL NEED:
- A sharp knife
- Tin snips
- Wire brush
- Heat gun (depending on the clamp used)
- A new hose
BEFORE YOU BEGIN
Proper maintenance and service procedures are vital to the safe, efficient operation of all motor vehicles, as well as to the safety of the person performing the work – Whenever you are working on your vehicle, we recommend that you follow these important safety rules:
- Do have a first-aid kit handy
- Do be careful when working around hot or sharp objects
- Do follow the manufacturer’s instructions for all products
- Do use safety stands under the frame or drive-on ramps if you must raise your vehicle
- Don’t run the engine without proper ventilation
- Don’t smoke when working around the engine
The best way to check coolant hose for the effects of ECD is to squeeze the hose near the clamps or connectors using the following procedure:
- Make sure the engine is cool.
- Use fingers and thumb to check for weakness, not the whole hand.
- Squeeze near the hose clamps. ECD occurs within two inches of the ends of the hose and not in the middle (see Figure 1).
- Check for any difference in the feel between the middle and ends of the hose. “Gaps,” or “channels,” can be felt along the length of the hose where it has been weakened by ECD.
- If the ends are soft and feel mushy, the hose is under attack by ECD. To avoid breakdown of the cooling system, we recommend replacing the hose immediately.
- Most hoses are basically installed the same way
- Remove the hoses being replaced. Drain the cooling system below the level you’re working. Most hoses should gently twist off after you loosen the clamp. Cut off a rusted hose clamp with tin snips. If the hose is stuck to the fitting, don’t force or pry it off. Doing so could damage the fitting. Instead use a sharp knife to cut the hose end and gently remove the hose.
- Check to be sure the fitting is not distorted or corroded. There should be no sharp edges or burrs, which could slice through the hose inner tube. It’s best to clean the fitting neck with a wire brush before installing a new hose.
- Slip the clamp onto the hose end and then slide the hose onto fitting.
- Make sure the hose is shouldered well beyond the fitting edge and the clamp is positioned between hose end and edge of the fitting. A clamp tightened on the edge of a fitting will eventually will cut the hose tube.
- It is always recommended that when changing a coolant hose that new hose clamps are installed as well. Check with your local NAPA Auto Parts store to ensure you have the correct style and sized hose clamp when you purchase your new hose. Alternatively, a thermoplastic PowerGrip SB clamps eliminates cold water leaks, won’t corrode and are maintenance free. These easy to install clamps offer unsurpassed sealing on all types of coolant hose – even silicone. Made from heat shrinkable thermoplastic these clamps are positioned over the top of the connector bead and heated with a heat gun to form a tight seal around the hose and housing. When installed properly, these clamps maintain a constant tension so they never need to be retightened even on out of round fittings.
- Make sure the hose clamp is positioned so the tightening device is easy to reach.
- In some cases where the replacement hose may not be an exact OEM duplicate, slight twisting or bending of hose may be required for installation. This is okay. However be sure the hose does not become pinched, or put into an abrasive or high heat situation without a protective sleeve.
- Proceed and tighten the hose clamp.
- Re-fill the coolant system. Be sure to check the strength of the engine coolant and replace it if it is not strong enough. Start the engine and let it run until the engine has heated up. Additional coolant may need to be added.
- Do a final visual inspection to ensure there are no leaks.