I have an early 65 Mustang D Code, 289 4V, Newly rebuild motor, new everything. First the lower radiator hose blew off and I lost all my coolant, so I double clamped the hose.It seems that water backs up into the lower radiator and up and out the overflow tube when the engine warms up. I pulled the thermostat and ran it without a thermostat. Still the same thing, engine gets hot water backs up into the radiator and out the overflow tube. I'm thinking about pullingthe water pump the see if the impeller is turning and if the impeller was installed backwards. Anybody have any other suggestions? I would greatly appreaciate it.

Thanks
Tom

 

Are you using a standard or reverse rotation water pump?

 

When I bought the pump I just asked for a water pump for a 64 1/2 Mustang and they ordered a pump and I got it on a couple of days. So I really don't know. I assumed it was a standard pump. It could only bolt on one way.