Pushing water out of radiator?

Guys have a brand new 545 in a 96 mustang and its got a alluim raditor it keeps pushing water out bad with the cap off. Water will go up then down then start shooting out the top. Did the same thing with the 466 in it. This motor is all new water pump is manual.factory electric fan and shroud. Thermostat is gutted out. We just cant figure it out. Thanks

Have you done a compression test?

Not yet motor runs great but we are going to check the cylinder pressure tomorrow.

What pressure cap?

Put the cap back on and watch the temp.

Could be the top hose is higher than the radiator trapping air. That can cause all sorts of problems.

rmk57 wrote:Could be the top hose is higher than the radiator trapping air. That can cause all sorts of problems.

You are correct. When I filled my 460 powered 81 Mustang's radiator up, I jacked the front end way up to get the air out, and then I never took the radiator cap off again....seriously, I should probably look in there once in a while...

Sorry I missed the cap off part.

The engine is higher than the top of the radiator. Did not think about that but there's no way to raise the radiator up any higher. Anything we can do to compensate this?

Other motor did have a blowed head gasket. Pretty sure this one does not its not got over 200 degrees

capncruncher1965 wrote:The engine is higher than the top of the radiator. Did not think about that but there's no way to raise the radiator up any higher. Anything we can do to compensate this?

Can you fit a remote radiator cap in the upper hose?

https://www.google.com/search?q=remote+radiator+cap&rlz=1C1CHZL_enUS748CA748&oq=remote+radiator+cap&aqs=chrome..69i57.4174j0j7&sourceid=chrome&ie=UTF-8

capncruncher1965 wrote:Guys have a brand new 545 in a 96 mustang and its got a alluim raditor it keeps pushing water out bad with the cap off. Water will go up then down then start shooting out the top. Did the same thing with the 466 in it. This motor is all new water pump is  manual.factory electric fan and shroud. Thermostat is gutted out. We just cant figure it out. Thanks

if its a hi flow pump it does push water out with cap off, whats it do with the cap ON?


one of MINES A GUSHER with the cap off, also depends on how the rad was made,and where the cap location is

jasonf may have a solution, I'd try it anyway. I know the early 60's FE Galaxies had a surge / expansion tank from the factory for the same problem your having.

capncruncher1965 wrote:Guys have a brand new 545 in a 96 mustang and its got a alluim raditor it keeps pushing water out bad with the cap off. Water will go up then down then start shooting out the top. Did the same thing with the 466 in it. This motor is all new water pump is  manual.factory electric fan and shroud. Thermostat is gutted out. We just cant figure it out. Thanks

I hope for your sake, it is something simple.

It could be combustion pressure migrating into the water jacket, if there is a porous place anywhere within an area which sees cylinder presure.

Thats our problem. Pump is high flo dam didn't think about that.going to run it some tomorrow will give a update tomorrow night. Really want to thank all you guys for trying to help us out.Best dam website ever!!!!

Finally got it fixed. Took out the AC condenser got the fan on high speed filled it with water dam thing ran cool. Thanks guys for all your replys.