Correct heater hose routing

[chengny]

I new the pressure side is on the Intake Manifold and the suction side came from the Water Pump but what one should be on the Top is the dilemma.

In any shell & tube or finned tube type heat exchanger (where the inlet and outlet nozzles are at opposite ends of the vertical plane), the flow of liquid should - whenever possible - be: in through the bottom and out from the top.

This arrangement accomplishes two things:

1. Since the liquid level has to completely pack the shell before it can exit out the top, it ensures that the shell is continuously being purged of any entrained air.

2. It also helps the tube surfaces receive the maximum amount of possible contact with the heating/cooling medium (this is also the reason that the two nozzles are offset from each other). If the flow was from the top down, it presents the possibility of "laning". IOW - the fluid could possibly just shoot right down the middle and never even contact much of the tube surfaces. With the openings for the inlet/outlet on opposite sides of the water boxes - and the medium required to overcome gravity - stagnant pockets within the area of flow are reduced.





For some reason I thought the Heater Core would be treated just like the Radiator, Have hot fluid travel from the Top to the Bottom of the Heater Core. That way if it wasn't totally 100% full it would not just blow bubbles.


The key difference here is that the flow through these types of radiators is of the horizontal crossflow design - as opposed to a heater core, where the flow is in the vertical direction (from bottom to top).

So even though - it appears from the arrangement of a radiators inlet/outlet nozzles - that the coolant flow is vertical (and from the top to the bottom), it isn't like that.

In actuality the flow through a radiator is from left to right. At it's most basic, a radiator is simply two vertically oriented tanks that are inter-connected by a series of tubes. The tubes are fitted with fins on the airsides to increase their effective surface area.

As the water pump circulates the engine coolant through the system, it forces the liquid to move from the inlet tank, through the tubes and then over into the outlet tank. The vast majority of the heat exchange done by the radiator occurs as the coolant passes through the finned tubes.

The main reason that the outlet is located as far down on the outlet tank as possible is to keep the inlet to the water pump's suction hose as submerged as possible. This provides the pump with a supply of liquid for as long as possible in the event of a major loss of coolant.