RE: my engine run video yesterday...

[Pastel Blue]

......

 

[Bentworker]

Pressure testing would be a good plan.

 

[4Vforever]

Agree with above, get hold of a pressure tester, hook it up to the radiator cap and give it about 30 PSI that way it should show up, usually when cold as well. Also you said it didn't leak on initial start up at the engine builders, so what has been put onto the engines coolant areas since eg: plugs, hose pipes, etc. All bolts around the cooling system tighten firmly, nothing loosened since then. Just check the basics first, then if nothing changes get hold of a pressure tester to find it. Always a bugger when these small niggles turn up, but that's just the joys of restoring cars.

 

[Pastel Blue]

Agree with above, get hold of a pressure tester, hook it up to the radiator cap and give it about 30 PSI that way it should show up, usually when cold as well. Also you said it didn't leak on initial start up at the engine builders, so what has been put onto the engines coolant areas since eg: plugs, hose pipes, etc. All bolts around the cooling system tighten firmly, nothing loosened since then. Just check the basics first, then if nothing changes get hold of a pressure tester to find it. Always a bugger when these small niggles turn up, but that's just the joys of restoring cars.

Yep, a bugger for sure....

 

[Bentworker]

Once you get it pressured up the leak should be easy to find. At least at that point you will know for sure what work is ahead of you. Hopefully it isn't leaking between the timing cover & block.