Specialty Hoses

Today's coolant hoses carry coolant to a variety of under hood equipment and not just to the radiator, thermostat, water pump and heater. In addition to the traditional upper, lower, bypass and heater hoses, vehicles also are equipped with small (inside diameter) molded coolant hoses that carry coolant to the carburetor housing, fuel injection throttle body, turbocharger, oil cooler, and other components. The coolant can act as a cooling or heat source, depending on the equipment and time of year. For example, the carburetor and throttle body use the coolant to heat the fuel in the winter to keep it from icing and cool it in the summer to prevent vapor-lock.

Changes in coolant hoses include branched hoses, hoses with quick connects and ferrule assemblies. Branched hoses, or "intersect" hoses as they are sometimes called, use a tee with a secondary hose for routing the coolant to a separate part of the cooling system. Usually the hoses are attached to the tee by rubber encapsulation or a metallic ferrule. 

Quick-connect hoses are now used frequently in domestic vehicles and occasionally on imports. They are found more often in vans than other vehicles because of their equipment options. Quick connects use male and female counterparts which are ferruled to the hose. When the two pieces are pushed or snapped together, the fitting seals the hose, in effect, replacing a clamp (Figure 1). 

 

Figure 1

 

 

Ferrule assemblies typically have a pipe or valve attached to a hose(s) with a ferrule. The main purpose for most of these specialty hoses is ease of assembly at the factory. It takes far less time to install a one-piece assembly than to install two hoses, two clamps and a pipe.

Small I.D. Hose

Hoses with inside diameters of 3/8-in. and below are becoming more prevalent. Gates has a line of approximately 400 molded hoses under 1-in. inside diameter, 48 of which are between 3/8-in. and 1/4-in.. The line also includes straight hose in 3/8-in., 5/16-in. and 1/4-in. sizes. Hoses with I.D.s this small are very pliable and have a small bend radius due to the wall thickness of the hose. This means the hose, whether molded or straight, can be bent quite a bit with no collapse. 

For example, the original hose connecting the manifold to the throttle body may have 5/16-in. inside diameter and is 8-in. in length with a 110¡ bend in it. The replacement hose has the same inside diameter, but is 9-1/2-in. long with a 90¡ bend. It should be possible to cut the required length off the replacement and install the hose with no collapse. This also is true when the hose is bent the opposite direction, from a 90¡ bend to a 70¡ bend. (Note: Don't be alarmed if the replacement hose is not identical to the original hose. Some are slightly different. Gates engineers trial fit hoses on vehicles before recommending them. Try it on! If it doesn't fit one way, reverse it and try it the opposite direction.)

Replacing Specialty Hoses

When replacing specialty hoses -- hoses with quick connects and ferrules -- it will be necessary to save the pipe portion of these connections. If possible, for easier access, these assemblies should be removed. After removal of assembly, clamp it in a vise or to a stationary object, such as a table. Do not over clamp, which could distort the assembly. (If the assemblies cannot be removed, use extreme caution not to damage hose nipples during the following procedures.) 

Using a cutting-type tool such as a hacksaw or small rotary hand grinder with a cutting blade (see Figure 2), carefully cut a slit lengthwise in the ferrule. Do not cut too deep and score the nipple. Always wear eye protection when using power tools. 

 

Figure 2

 

 

After the ferrule is split, spread it open and remove it from the assembly (see Figure 3). Remove the existing hose form the nipple. 

 

Figure 3

 

 

If the hose is stuck, carefully slit the hose lengthwise and peel it off the nipple. Again, avoid cutting too deep and scoring the nipple. Check the nipple for damage and, if required, clean it with a wire brush. 

Compare the new hose with the old hose and make any necessary trimming. Slide new clamps over the replacement hose and install the hose over the spouts (see Figure 4). Install new hose over nipple and secure with new clamps. To simplify installation of hose, lubricate the inside with coolant before sliding it on the nipple. 

 

Figure 4

 

 

Quick-Connect Hose

If the assembly has a quick-connect attachment, remove it by pressing the "ears" of the fitting together. There is a tool available to expedite this, but with a little patience it can be achieved without it. When the fitting is loose from its mooring, slowly slide the female part from the male, making sure not to lose any of the nylon or rubber O-rings. If O-rings remain on the male spout, remove them and insert them back into the female in the same order they came out. 

There are two ways to replace the hose with quick-connect fittings: 

 

1. Remove the ferrule that holds the fitting to the hose as instructed above. Compare the new hose with the old hose and make any required trimming. Install the new hose over the nipple of the female fitting where the ferrule was removed. Clamp the new hose to the female fitting and reinstall over the male spout (see Figure 5). All O-rings must be present and in the same order for the fitting to seal.
   Figure 5  

    

    

2. Throw out the female part of the fitting and install the new hose over the male spout (see Figure 6). The spout usually is slightly larger than the inside diameter of the new hose. Lubricate the hose with coolant before installing. Slide the hose past the raised bead of the spout and clamp the hose behind the bead.

    

   Figure 6

    

    

Save $$$

Why is it necessary to do all this extra work? First, certain OEM hose replacements will need the same replacement procedure and second, the cost of replacement is significantly lower than replacing the full assembly -- as much as 80 percent lower. 

Small molded coolant hose play an important part in the cooling system, however, certain aspects of hose replacement have changed. Although coolant hoses appear to last longer today than before, there is no way to tell if a hose has internal damage until it fails. 

For this reason, Gates continues to suggest hose be replaced every four years. Fleet vehicles, vehicles in severe weather states, or vehicles with extraordinary circumstances (i.e., overheating, oil leaks, major engine work, etc.) should have their hoses replaced more frequently. 

Also, it's a good idea to carry an extra set of replacement hoses for emergencies. It could save trouble and unnecessary expense if a hose fails on the road.