Hey Jeff,

If you have one of those infrared thermometers, let the car idle with the cap on, and take temp readings on the thermostat housing, upper and lower radiator hoses, and various places on the radiator.  That will help see what is going on, temp wise.

Regarding factory specs, it the drivers door is original to the car, and if the id tag is still riveted to the door near the latch, you can enter those numers on an internet "mustang decoder" website, and he can learn a few things.  Being a 68, he could order a Marti report, online, and learn exactly what the car came with.

M1Mustang69 wrote:

That's a great idea Tim with the thermo-thingy. I never thought of that. So if upper is hot and lower is not (visa versa) what would either of these typically indicate?


Also, do all ford pumps circulate the same direction? Or is it possible the impeller is spinning in the wrong direction depending on the year/cast of the pump?

If the upper hose is warm enough to indicate thermostat has opened, and the radiator doesn't warm up all over, there could be a restriction in the radiator.  This could be the case if the radiator has not been flushed, and the car is not driven long enough, often enough, to keep substantial coolant flow.  Crud accumulates in the lower part of the radiator and restricts flow.

There are serpentine belted Ford water pumps that are "reverse rotation" water pumps.  Who knows what pump the parts house gave to the person that installed the pump....  If the mechanic that replaced the water pump was kind enough to show you his receipt for the pump he purchased from his supplier, you would have a good idea of what pump it is.
 

Last edited by TimC (10/10/2016 8:16 AM)

Well I only know on my 69 351W I can see very good flow at idle (modified with mild cam).

I changed his bypass because it was kinked, someone used the reg hose, not manufactured bent) and I changed the upper cause it was ballooning. 

He recognizes slight over-heating after extended idle, usually at higher external temperatures.  I assumed the bypass would rectify this, but his is when I Noticed the lack of flow from the rad port and hen the slow rising and overflow.