Radiator Core

eliminates excessive splashing and distributes the water

the air entering the radiator, increasing the cooling

uniformly over the tank. The cutaway view (fig 3-3)

capacity Round tubes are easily broken by the expansion

illustrates the construction of a stamped metal tank.

of freezing water, whereas oval tubes (fig. 3-4) will be

distorted to some extent before breaking.

3-3.

Radiator Core

a. General. Radiator cores are made with a large

surface area of very thin sheet metal so that the heat of

the water passing downward through the small passages

may be readily transferred to the air. The water passages

of the core are known as the "prime" radiating portion.

Heat passes from the circulating water to the water

passages and then to the fins where it is expelled to the

Figure 3-5. Tubes in straight row.

passing air. The secondary radiation is as important for

cooling as the primary radiation, be careful not to damage

the fins.

b. Tubular Core

(1) Core, figure 3-4, Is made of a multitude of vertical

tubes, generally 1/4-inch in diameter (drawn or seam-

welded) soldered through thin sheets of metal at the top

and bottom, called header plates. The header plates form

mounting pads for the upper and lower tanks and permit

no passage of water from the tanks to the core except

through the tubes.

Figure 3-6. Tubes in staggered row.

(3) The radiating surface of these tubes is

occasionally increased by spiral fins on each tube, or

much more commonly, as in figure 3-4 by thin sheets of

metal (horizontal fins) extending all the way across the

radiator, 1/8 to 3/16 inch apart, in contact with each tube.

The front edges of horizontal fins are usually crimped or

bent back to a double thickness which strengthens the

radiator core. In most radiator cores the fins are soldered

to the tubes to speed the heat transfer.

3-4.

Radiator Supports

Figure 3-4. Tubular core.

Radiators in a motor vehicle are usually sup-

(2) The tubes are generally spaced about 3/4 inch

apart, in two to four straight or staggered rows (figs 3-5

and 3-6) 1/2 inch apart, across the width of the radiator. In

a staggered row, twice as many tube rows are exposed to

3-2