Steve29 Posted March 29, 2019 Share Posted March 29, 2019 I have had trouble with foam in the cooling system that at times comes out from the radiator cap. It an open cooling system, the engine has good compression, the radiator core and bottom tank are new, the water pump is in good condition and has good packing, there are no leaks in the hoses or elsewhere, no water in the oil, and no oil in the radiator. I took the antifreeze out but did not flush out the system, and replaced it with water and a can of standard anti rust and water pump lube. This did not fix the problem, there was still foam. Has anyone else had this problem or can suggest a fix? I am currently thinking of trying No-Rosion and start with their flush product. Any thoughts or ideas would be appreciated. Link to comment Share on other sites More sharing options...
Guest Posted March 29, 2019 Share Posted March 29, 2019 Foam means there is a leak into the coolant. Head gasket, cracked head, cracked block, etc etc. Maybe it only leaks when hot or at some place between cold and hot. As Five Alive said in the movie "Input"... "Need Input". Link to comment Share on other sites More sharing options...
trimacar Posted March 29, 2019 Share Posted March 29, 2019 I had foam start in one of my cars, water pump seal was fine, but water pump grease was gone and pump was sucking air through fitting. Put in New, correct, water pump grease, not just any grease, problem (foaming) went away....but you HAVE to use water pump grease... 2 Link to comment Share on other sites More sharing options...
edinmass Posted March 29, 2019 Share Posted March 29, 2019 It’s probably sucking air through the packing. Try running straight water with cutting oil in it. It will solve the problem. Link to comment Share on other sites More sharing options...
John_Mereness Posted March 30, 2019 Share Posted March 30, 2019 (edited) I agree that it is the water pump - needs a wax based water pump grease (www.restorationstuff.com) Option B is that one of the radiator hoses is collapsing under load as it does not have a spring on it (look to suction side of pump) - and that stresses whole system And, option C is bad head gasket or a crack Saw someone mentioned a clogged radiator - same effect as a collapsing hose under load. Edited March 31, 2019 by John_Mereness (see edit history) 1 Link to comment Share on other sites More sharing options...
Grimy Posted March 30, 2019 Share Posted March 30, 2019 I have had foaming issues in unpressurized cooling systems (more than one) where there was 50% antifreeze (EG) despite freshly rebuilt water pumps with modern seals. EG in unpressurized systems will foam at speed and force coolant being moved to the top tank out the overflow. Soon after I acquired my 1934 Pierce, I drove it on a 1,500-mile round trip, mostly at 55 mph. On the road, every 100 miles or so, I had to add about 4 qts of water, replacing the 50% EG coolant, and the rate of consumption decreased in a linear manner. When I returned home, I flushed all the antifreeze and replaced with distilled water and anti-corrosion additive (Pencool), which I can do because my climate (at least in the garage) never drops below freezing. Now, 13 years later, the same car with the pump never touched, will require a 6-oz. top off every 700 miles or so. I've **heard** that low-silicate EG antifreeze has less tendency to foam in unpressurized systems but have not tried it. Link to comment Share on other sites More sharing options...
Guest Posted March 30, 2019 Share Posted March 30, 2019 My Pontiac with a crossflow unpressurized rad and 50/50 antifreeze very, very seldom has ever needed a top up. Just change the coolant every couple of years. On long trips of 400 to 500 miles per day for a week or ten days at a stretch have never added to the coolant and have never ever had foaming. Original style bushing and packing seal. Link to comment Share on other sites More sharing options...
Spinneyhill Posted March 30, 2019 Share Posted March 30, 2019 Same for me with a 1930 Dodge Brothers Eight. Normally need no top-up of cooling fluid and never seen foaming. I use 50-50 EG antifreeze and tap water. Even when it was burping (boiling) back through the system there was no foam. Somewhere, you must be churning air if you are getting foaming. So where could it be coming from ? The water pump as stated; leaking head gasket as stated; cavitation at water pump - although that would result in erosion of the pump body and impeller; cavitation at cylinder sleeves - Penray talk about cavitation around cylinder sleeves https://penray.com/cooling-system-techfacts/cavitation-in-cooling-sytems/; what about low pressure ("suction") resulting in cavitation in the water pump inlet hose because the radiator is (partly) blocked?; a tiny leak at the water pump inlet; an air lock in the cooling system, for example under the thermostat, which might be very close to the water pump; etc. So I say find that air ingress! Link to comment Share on other sites More sharing options...
Steve29 Posted March 31, 2019 Author Share Posted March 31, 2019 Thanks to all of you for your help. The grease question is a good one that I haven't tried and will. The water flow into the top tank is "robust" so the issue of air being sucked into the system from the water pump seems very likely. As I mentioned in the post, when I drained the antifreeze l didn't do a thorough flush that I will now do. That will eliminate the antifreeze as the cause of the problem. Link to comment Share on other sites More sharing options...
John_Mereness Posted March 31, 2019 Share Posted March 31, 2019 (edited) Antifreeze is not your issue. Sidenote: if running for the summer with water, then add a water pump lubricant (I bought my last quart at NAPA) Edited March 31, 2019 by John_Mereness (see edit history) Link to comment Share on other sites More sharing options...
Mikefit Posted April 2, 2019 Share Posted April 2, 2019 My 23 Buick has all the same symptoms as you have I though H head or head gasket cracked block it was the suction side of the pump getting air and forcing into the radiator my case I tightened the packing nut problem stopped just that quickly. Mike Link to comment Share on other sites More sharing options...
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