Section II. RADIATOR CLEANING

ported at the top and bottom. The top support is simply a

tie rod extending to the cowl or cab front, the lower

supports are fastened to the side rails or to a strong cross

member at the front of the chassis. Radiator mountings

should prevent all twisting strains, road shocks, and

engine vibration from reaching the radiator core, which at

best is delicately constructed and easily damaged.

b. The cast-type heavy-duty truck radiator shown in

figure 3-1 has mounting brackets at the bottom of the side

rails of the chassis. Small springs (coil or flat leaf) or

rubber blocks are placed between the brackets and side

rails to cushion the radiator.

c. Many radiators are housed in pressed metal

shells. Fastened to the frame of the vehicle, the shell

receives all the distorting forces that the frame receives. A

shell may be detachable from the radiator assembly or

built in it rests on a cross member of the frame, secured

Figure 3-7. Radiator in U-shaped shell.

by studs and nuts, or is bracketed to side members, like

the cast-type radiator. If the lower tank rests on the

3-5.

Radiator Fittings

supporting member, soft pads of woven material are

inserted to absorb road shocks.

d. The radiator shell shown in figure 3-7 consists of

The radiator fittings are the filler neck and inlet connection

of the upper tank, and the outlet connection and drain

a U-shaped steel band, which is bolted to the front cross

valve of the lower tank. These are made of malleable iron

member of the chassis frame by two capscrews. Brackets

or pressed metal. When they are manufactured as

on the pressed steel side members of the core are bolted

separate parts, they are brazed, soldered, bolted, or

to corresponding brackets on the U-shaped shell, holding

riveted to the tanks.

the radiator assembly rigidly, and greatly facilitating its

removal for repairs. If the radiator is spot welded and

soldered to the mounting shell, the entire unit must be

removed from vehicle before the core is accessible.

Section II. RADIATOR CLEANING

surfaces in sufficient quantity to restrict the air flow through

WARNING

the radiator and decrease its efficiency. Spray cleaning is

Flux, caustic solutions and cleaning acids can

then necessary.

cause skin irritation. Wash immediately with soap

and clean water. If the skin comes in contact with

3-7.

Determining Extent of Clogging

these.

To determine how badly a radiator is clogged without

3-6.

General

removing it from the motor vehicle, test it with a flow tester

(para 3-18) which indicates the exact amount of gallons of

Radiator cleaning has three purposes to restore efficient

water per minute that will flow by gravity through the

cooling, to facilitate soldering, and to remove obstructions

radiator. Checking this reading against the floe rate of a

to water circulation. Various chemical salts and dirt found

new radiator will indicate the extent of clogging.

in the water of different localities, together with grease and

oil that find their way into the cooling system, collect inside

3-8.

Flushing

the water passages of the radiator and insulate the water

from the metal or stop circulation. This overheats the

a. General. Flushing is a process of forcing water

engine. Rust, disintegrated rubber hose, and accumulated

deposits from antifreeze or stop-leak preparations will

by air pressure (approximately 5 pounds) through water

have the same effect. The water passages may be

passages of the radiator core or engine block. The same

cleared by pressure flushing, vat cleaning, boiling or rod

equipment is required for all methods of

cleaning. Dust, limit, and bugs often adhere to the fin

3-3