Replacing Hoses
The basic process of changing a hose is quite simple (see Figure 12-8), but there are differences, depending on the type of hose you're replacing.
- If the hose is a vacuum hose, you'll find literally nothing in it. Just loosen the clamps, remove the hose, slide the new clamps on the new hose, slip the ends of the hose over whatever they connect to, and tighten the clamps.
- Caution: If the hose is a fuel hose, have a professional replace it. Fuel is not only highly flammable, but it's also toxic. The danger, effort, and time necessary to clean up any spills and to dispose of everything properly at a hazardous waste center just isn't worth trying to tackle this relatively inexpensive job yourself.
- If the hose contains liquid under pressure, before removing the hose, be sure that the engine is shut off and the liquid has been allowed to cool so the pressure is released.
To prevent leaks, some manuals suggest putting a water-resistant sealant on the ends of the fittings to which the hose connects. Because these sealants tend to make the hoses difficult to remove when you need to replace them again, I suggest that you try it without sealant first. In most cases, if the hose is the right one and the clamps are on tight enough, you should be able to get by without sealant. If the hose leaks, you can always go back and use the sealant as recommended.
- If the hose is a radiator or heater hose, to catch the coolant and water that will run out of the system, you'll need a bucket or pan that holds at least two gallons of liquid and will fit under the radiator drain valve (called the petcock) that drains the radiator.
Caution: Never allow coolant to drain onto the ground.
If you haven't flushed your cooling system and replaced the coolant in the past year, do so at the same time you replace the hose. (See the "Flushing Your System and Changing Your Coolant" section for instructions.)
Car Smarts: Some newer engines have cooling systems that need to be bled. If your engine falls in this category, the cooling system contains special bleeder screws. If you're not sure what type of system your vehicle has, check the owner's manual or ask a mechanic before you undertake this job. To do it properly, you need to follow instructions in the owner's manual or a service manual for your vehicle.
Follow these steps to replace a radiator or heater hose:
- Make sure that the parking brake is on and that the car is in Neutral or Park before you start work.
- Remove the pressure cap from the radiator or coolant reservoir, and place a bucket or drain pan under the radiator drain valve.
- Open the drain valve, allow the coolant to drain into the container, and then close the valve.
- Remove the clamps at both ends of the hose.
As I say in "Buying and replacing hose clamps" earlier in this chapter, you're going to replace those clamps, so if you can't remove them easily, cut them off. (If you haven't read that section, do so before going any further.)
- Carefully twist the hose to remove it, and use the container to catch the liquid that drains from it.
Be gentle when removing the hose. If you're not careful, you coulddamage the radiator.
- Use any degreaser or just a damp clean rag to clean the fittings that the new hose will attach to, and install new clamps over the hose (refer to Figure 12-8).
- Install the new hose, attaching and clamping one end securely in place before you tackle the other end.
Make sure that the hose won't interfere with any moving parts or touch the engine when it's hot, and that the clamps are tight.
- If the coolant that you drained is fairly new and your container was clean, pour the liquid back into the system; otherwise, refill the system with a 50/50 mix of fresh coolant and water.
If you're replacing the coolant, see "Keeping coolant out of the mouths of babes and small animals" for instructions on disposing of the old stuff safely.
- Start the engine and add more water and coolant as the level in the radiator drops.
Don't fill the radiator to the top of the neck or the coolant reservoir up to the "MAX" line until the thermostat opens. When the upper hose is hot, the thermostat has opened. Then it's okay to top off the radiator or the reservoir.
- Replace the pressure cap.
If your engine is the type that needs to be bled, do so now, following the instructions in the owner's manual or service manual for your vehicle.
- Run the engine and double-check that the clamps are nice and tight so that no liquid leaks out.