How I tested my 454 for block water jacket leaks

[hpcrank]

Greetings

To verify what was the source of water in my engine oil (454 Chevy/Mercruiser Gen. IV) I did the following.

• Remove the thermostat housing including the hose manifold.
• Remove engine water circulating pump.
• Fabricate 3/8" thick steel block off plates for the two water pump openings in the block and install over openings using gaskets.
• Fabricate a 3/8" steel block off plate to cover the thermostat opening on the intake manifold.
• Drill a hole in the thermostat block off plate large enough to insert a tire inflation stem Schrader valve, you need the type that has a nut and gasket on the back side.
• Fabricate a plug for the bi-pass hose on the front of the intake manifold, install and clamp.
• Install the thermostat block off plate with gasket and pump in 15# compressed air. Use tire gauge to check pressure (you will loose a little air each time you check with a gauge so don't do it too often).
• My block was good, it held a constant 14.5# air pressure for five days. Now I know I need new exhaust manifolds and not a new engine.

Hope this helps someone.

V.R.
Hpcrank

 

[scoflaw]

gets way simpler than that. Don't take anything apart.
Remove the 2 sensors on the t-stat housing that have npt thread.

screw a shrader valve into 1 and a pressure gauge into the other.
KISS method.