Update- it is still foaming with the new head gasket and tested crack free head. I have re-torqued the head bolts three times, no movement the last time. I purchased a exhaust gas in coolant tester and it stays blue so no combustion gases in the coolant. I should add it runs cool and runs very well a little slow going up hills in third but I suppose that is the way it is.
So that leaves the water pump (has been rebuilt with new shaft) has a tight packing nut, coolant hoses and elbow, possibly the new drain cock I put in the lower rad outlet, and the hole in the water distribution tube inside the top tank which some have said would not make a difference and I agree. I am also using the coolant least likely to foam.
I put new bolts in the repro hose clamps and they are tight and I also used sealant on the hose connections.
Hello Dave, I have just read all of this post, A lot of good discussion to help you. So , I was going to suggest what bearsfan did with his 1929 cooling , and place a visible chamber, in the upper radiator hose. With the engine running you should be able to see if it is actual bubbles forming in the coolant. My second suggestion would be to drain and save your coolant, flush the system again with clean water, watch the system with the clean water, and check again for bubbles or foaming.
I am also thinking that it may be fluid turbulence you are seeing, may not foaming. I know that when I take my radiator cap off my 1939 sedan, the coolant returning to the radiator is turbulent, just from the moment through the system.it runs as cool as could be, and only rises in temperature during extended highway speeds.
My other idea is , that we often compare our old chevies to the standard of new modern vehicles, which use a pressurised coolant system, which acts to prevent coolant turbulence and bubbling, A Coolant system in a 1931 , ( and 1939) Chevy is NOT A pressurised system.
I know others have suggested the sealed bearing water pump, if you are still concerned, replace your existing pump with the new sealed bearing type.
Thanks Jack for the ideas. There are no bubbles or foaming with plain water and I did buy some soluble oil and may go that way in the summer but there is always an outside chance of my shop getting below freezing.
Let's say there are bubbles being formed what would be causing them if there is no exhaust gas in the coolant and all the other usual suspects have been corrected or checked?
That is a thought. I am using Lubriplate water pump grease which is a change I made from the red stuff Synder's sells. Don't know if it has soap but will find out.
This is the answer the folks at Lubriplate sent me; Greases do not cause foaming. Air entrapped in liquids causes foaming. Thank you for contacting us.
if it does not foam with plain water then it has to be something that was added to the water, if all other conditions remain the same as that is the only variable changing.
maybe a combination of the additive and something already present in the water ?
AACA - VCCA - Stovebolt - ChevyTalk Love the Antique Chevrolet's from 1928-1932 The Beauty, Simplicity, History, and the Stories they Tell
The Lubriplate people told you correctly. Foam is air trapped in liquid. Anything that reduces the surface tension of water will help stabilize water containing foam. Soaps, detergents, ethylene glycol are some common agents. Chemicals that destabilize bubbles will cause them to brake open. Silicones, oils and similar agents are commonly used.
Running water and soluble oil I tried tightening up the packing nut beyond what would be reasonable and it foamed worse than ever. Decided it must be something in the pump. Pulled it and the packing and it looked okay. Then I noticed a flaw in the casting under the gasket which was a hole going into the inlet of the pump. If this was pulling air in around the gasket that could be the problem. Put a new (old style) pump on and tested it today. No hint of foam with the water and oil. Not high fiving yet until run it some more and then with anti freeze.
Any thoughts on that hole being the cause of the foam?
could be if it is allowing a path for air to flow. sucking in air. figure pump running creates a vacuum of sorts and pulls in air.
been working with metal castings 20+ years, (plus composite moldings) it is amazing to see a new pump casing come in, cast iron, ductile iron, etc, and know the walls are approx 1" thick, pressure test it and it leaks. then flood it (fill with water) and pressurize it and see it start to sweat (leak water everywhere) literally looks like it is sweating. drop it in the pressure tank, large acrylic tank full of water, and then pressurize the pump with air, and watch it blow bubbles !! seen plenty of crazy stuff over the years with castings !!
AACA - VCCA - Stovebolt - ChevyTalk Love the Antique Chevrolet's from 1928-1932 The Beauty, Simplicity, History, and the Stories they Tell
Loose radiator hoses can also be a source of air as well but not as common. That was a problem with the early silicone radiator hoses. They were too soft and even with clamps allowed air to be drawn in on test vehicles. Nearly drove us nuts until we put glass tubes in place of sections of hose so we could actually see the air. That was on systems with 15+ psi radiator caps.
Due to the cooler weather I took the water/soluble oil out and put antifreeze back in. No foaming what so ever, so the problem was a porous water pump casting.