Boats have accumulators in their fresh water systems to prevent the pressure switch on the pump from cycling. It is basicaly a metal container with opening on the bottom connected to the pressure side. The air can never be purged and acts as a spring to smooth out the pressure pulses.
Buly

It is an accumulator.

 

Used in thousands of hydraulic systems.

 

The RX-2 and RX-3 had this setup. I use it on the race car since the 80s. I use an RX-2 bottle, but many different bottles will work fine.

 

You put the bottle abiout 1/3 full of coolant, and run the engine through a few heat cycles. The tank will be empty of coolant and the engine will be empty of air.

 

I have a shrader valve in my bottle, so I can charge the bottle to the cap reliefe pressure before I start the engine.

 

The bottle can be anywhere. Mine is on the floor of the car with 4 feet of hose to connect to the top of the radiator. The pressure cap on the radiator has no guts in it.

 

Works great.

 

Lynn E. Hanover