improved cooling mod for 4AC engine using heater hose shunt

[rickhart]

I can't believe I didn't see this 20 years ago----just assumed the design engineers had it right.

The 4AC engine has two cooling tubes on the left (driver) side. The lower hose goes to the manifold containing the thermostat and inlet (to waterpump) tube. The upper hose goes to the heater temperature control valve---controls the amount of hot coolant, if any, going through the heater core. When the valve is closed hot coolant is trapped inside the engine and the engine is only cooled by way of flow through the lower hose. This tends to allow the upper portion of the engine to be insufficiently cooled.

So, I did the following:

About 4" or so from the upper hose clamp, I cut the hose and installed a 3/4" brass "T" with screw clamps. I then cut the return (from the heater core) hose perpendicular to the above "T" and also installed a 3/4" brass "T" and about 3"of 3/4" heater hose to connect the two. This bypass hose (shunt) allows hot coolant to always flow through the upper engine to the thermostat manifold even when the heater is OFF, such as when running the AC.

The only drawback is that less hot coolant flows through the heater core than before. This isn't a problem for me in Atlanta, but if I lived in a colder climate, I might use a spring clamp on the bypass hose to force more coolant through the heater core.

I welcome any comments or criticisms on the above procedure.