Coolant loss

[GPALMISCIANO]

I'm losing coolant in my 351 PCM engine. no external leaks, no coolant in oil, no colant in transmission fluid. Haven't done any other checking yet. Plan on pulling the plugs and checking them,doing a compression check, and trying to pressurize the coolant system while the plugs are out and cranking it over to see if any coolant comes out of any of the spark plug holes. Any other thoughts or suggestions?

 

[makomark]

pressure tester is a good starting point. If your plan doesn't show the source, other areas to check: hose clamps (yes, lots of hoses but each end is a potential leak source), seal in the circulation pump, and the exhaust manifold outlet joints.