In the cooling
system, the radiator is a heat exchanger that removes the heat from the coolant passing
through it. The radiator holds a large volume of coolant in close contact with a large
volume of air so heat will transfer from the coolant to the air. The components of a
radiator are as follows:
center section of the radiator made up of tubes and cooling fins.
metal or plastic ends that fit over core tube ends to provide storage for coolant and
fittings for the hoses.
NECKThe opening for adding coolant. It also holds the radiator cap and overflow
COOLERThe inner tank for cooling automatic transmission or transaxle fluid.
fitting on the bottom tank for draining coolant.
radiator consists of a series of tubes extending from top to bottom or from side to side
The tubes run from the inlet tank to the outlet tank.
placed around the outside of the tubes to improve heat transfer. Air passes between the
fins. As the air passes by, it absorbs heat from the coolant. In a typical radiator, there
are five fins per inch Radiators used in vehicles that have air conditioning have seven
fins per inch. This design provides the additional cooling surface required to handle the
added heat load imposed by the air conditioner.
classified according to the direction that the coolant flows through them. The two types
of radiators are the downflow and crossflow.
downflow radiator has the coolant tanks on the top and bottom and the core tubes run
vertically. Hot coolant from the engine enters the top tank. The coolant flows downward
through the core tubes. After cooling, coolant flows out the bottom tank and back into the
crossflow radiator is a design that has the tanks on the sides of the core. The core tubes
are arranged for horizontal coolant flow. The tank with the radiator cap is normally the
crossflow radiator can be shorter, allowing for a lower vehicle hood.
of a radiator is as follows: The upper tank collects incoming coolant and, through the use
of an internal baffle, distributes it across the top of the core.
core is made up of numerous rows of small vertical tubes that connect the upper tank and
the lower tank. Sandwiched between the rows of tubes are thin sheet metal fins. As the
coolant passes through the tubes to the lower tank, the fins conduct the heat away from it
and dissipate this heat into the atmosphere. The dissipation of the heat from the fins is
aided by directing a constant air flow between the tube and over the fins.
lower tank collects the coolant from the core and discharges it to the engine through the
overflow tube provides an opening from the radiator for escape of coolant if the pressure
in the system exceeds the regulated maximum.This will prevent rupture of cooling system
oil cooler is often placed in the radiator on vehicles with automatic transmissions. It is
a small tank enclosed in one of the main radiator tanks.
transmission fluid is hotter than engine coolant, heat is removed from the fluid as it
passes through the radiator and cooler.
radiators, the transmission oil cooler is located in the lower tank. In a crossflow
radiator, it is located in the tank having the radiator cap. Both tanks are coolant outlet
from the cooler extend through the radiator tank to the outside. Metal lines from the
automatic transmission connect to these fittings. The transmission oil pump forces the
fluid through the lines and cooler.