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Like Jerry and his 29 I am also trying to work out the bugs on my 31 since it is back on the road. I did a search and it was fun reading the old reply's from Chipper, Gene, Mr.Mack, JYD , and others. After all that I should not have questions but I am slow.

So I believe air is coming past my water pump shaft causing it to foam when the engine is slowed down. I have some water pump grease and coolant coming out of the pump that is visible on the shaft . I did tighten the packing nut with only slight help. I added a ring of packing and it is still foaming when the engine slows coming to a stop.

The engine is not over heating and runs well.

Question # 1 is how tight should I go on the packing nut or where do you stop before you cause problems with the shaft over heating?

Question 2# I noticed a small hole in the radiator inlet pipe, inside the radiator just under the cap. The hole points up towards the cap. Watching it run at idle does not look like it would be a problem. Looks like a rust hole. Could this be causing my problems?

Thanks

Dave

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Hello Dave39MD,
When you say coolant and pump grease is appearing on the shaft ahead of the water pump housing, is that the foaming that you are seeing at that location or somewhere else? Try removing the fan belt and wobble the fan/water pump shaft to check for loose play between shaft and bushing. Too much play will continue to work the packing seal and internal coolant will work past and leak. I'd say that you can tighten the packing until you feel resistance in shaft rotation just beginning. Then reinstall fan belt and tension to just snug, not loose-not tight and see how that works. No clue as to the hole under the radiator cap that you see. Is it above coolant level? I would not think that there is air in system, unless low on coolant. edit. Maybe air and coolant are swapping places like Chipper suggests.

Last edited by Harrys31coach; 06/19/22 07:18 PM. Reason: What Chipper says.
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Harry, Thanks for the reply. The foaming comes out and around the rad cap. The water pump grease and a slight amount of coolant is coming out from the pump to the shaft and the area below the shaft on the pump.

Dave

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If the water pump shaft is galled or too worn new or tight packing may not be enough.


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Originally Posted by Dave39MD
Question # 1 is how tight should I go on the packing nut or where do you stop before you cause problems with the shaft over heating?

It should leak, just not much. The water is the lubricant. It would be nice if the leak was extremely slow. A drop every 15 minutes or so might be really nice. Sneak up on it. keep making it leak a little less. On my packing nut water pump I can reach under there and it is always damp, but I never see any water on the ground. If the nut is extremely tight and still leaking noticeably the nut is probably bottomed out and it needs more packing. If more packing won't do it, The pump probably needs an overhaul.

Originally Posted by Dave39MD
Question 2# I noticed a small hole in the radiator inlet pipe, inside the radiator just under the cap. The hole points up towards the cap. Watching it run at idle does not look like it would be a problem. Looks like a rust hole. Could this be causing my problems?

I really doubt it could be a problem. If your water pump leaks excessively that is almost certainly the cause. If the water pump isn't leaking excessively, and you are using ethylene glycol coolant, you might need some coolant that foams less (Valvoline/Zerex G-05 is a good choice). It wont compensate for an water pump that leaks air though.

Last edited by bloo; 06/19/22 11:15 PM.
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Thanks Chipper and Bloo!

I am not 100% but I think I put a new pump on it when I started this adventure 10 years ago. I do have pumps and shafts here if that turns out to be the problem. What is visible of the shaft does look new.

I put one ring of new packing in and it is tighten up a little past snug. I can't see water leaking but the depressed area under the shaft is wet when I get back from a run, grease coming out of the packing nut on to the shaft. I will run it again this morning and see what happens. I'll find some Zerex G-05 and give that a try as well.

Dave

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Ran it mid morning and there was no surge of foam at the usual spots in my test run. When I got back to the shop inside the cap was foamy as was the over flow tube discharge. Water and grease still getting by the packing so I am taking this as a sign to tighten up a little more.

Found the G-05 at NAPA.

Dave

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No change today. I did have my laser temp gauge and as soon as I got back I hit the packing nut and it was 142 F same as the stat housing and rad inlet. Do you think this may be reasonable? My thinking is if I have it too tight it would be getting hot so I may have a ways to go in tightening it. A slight amount of grease still easing out at the packing nut and shaft but very little water at this point.

I must not have done anything with this pump because I believe I could get another ring of packing into it.

thanks

Dave

ps This is a fun car to drive, I knew it would be so it kept me going.

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Just slow down the leak as much as you possibly can, but don't quite stop it. When you stop it the packing and shaft will burn up fairy quickly. It really is that simple. In the future if it starts leaking more, tighten it more. Great news to hear that it is on the road!

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Thanks Bloo

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we call it a controlled leak wink use packing in a lot of industrial pumps in various applications. depending on the application how many drips per second/ minute you need. basically serves as the LUBE for hte packing and shaft. too loose and you loose your fluid, too tight and you burn up shaft/packing. depending on what you are pumping which cost you more wink


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Thanks Jerry.

I guess I am looking for that point where air is not getting past the packing but the shaft stays cool with a slight controlled leak. I still have some foaming. I put better bolts in the repo hose clamps on the bottom hose yesterday just in case it was not tight enough even though I did use a little sealer on the connections.

Trying to do one thing at a time so I know what caused the foaming.

I think my plan is one more test run then a new water pump, then the new antifreeze.

I hope your 29 is progressing

Dave

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Hello Dave39MD,
Looking at 'The Filling Station' online catalog with regards to water pump parts for 1931 Chevy:
RW-145 water pump rebuild kit: $169.50
VT-27 water pump grease: $ 17.50
RW-220T water pump packing: $ 3.95
WP-836259 water pump: $ 195.00
To me everything seems pricey so before throwing out or rebuilding your current water pump, maybe you can do some testing with your pump using; Aqua Shield Grease. Look it up and read the description. It does say to use gloves as it clings to most anything.

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Thanks Harry, I agree on making sure before I change any parts.

Bloo, I re read your AACA test. I do remember reading it but since I never had a foaming issue it did not stick.

It is odd that after I ran the Evapo rust treatment I refilled with anti freeze and I bet it was the same O Reilly's you had a problem with. The first time in 50 or so years of having a foaming problem. I will confirm when back to the shop.

I think I may just try the g 05 and see what that does. Maybe loosen up the packing nut a 1/4 turn to get it a little wet.

Thanks for the time and sharing of the test!

Dave

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Thanks Bloo!

I put the Zerex 05 in and ran it hard to my usual turn around spot and ran it hard back. Not even a hint of foam .I did loosened the packing nut a flat and have a hint of water coming out.

Looks like all I need to do is find a top and upholstery shop.

Thanks for everyone's suggestions.

Dave

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Well the foam came back but very light. I removed the water pump to check the shaft and put a rebuilt pump back on. The anti freeze is making a real mess on the new paint so I went with water. I am not sure if water even foams but there wasn't any after a long hard drive. I will also attach picture of the shaft to see what you think, it does not look real bad but I am not sure. Found what I think is a crack in my two blade fan so I replaced it with a four blade. Any ideas if the four blade is more or less a period replacement (picture attached)? I know there was a post or G&D article on fans but can't find it.

Thanks

Dave

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Here is a link to ID the fan blade:
https://1931chevrolet.com/specs9.htm
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That shaft looks like it would probably work to me, but it's hard to tell from afar. Maybe try some more packing? It must be sucking air somewhere, and the pump is usually a good guess. Water doesn't foam normally. The G-05 completely solved the foaming problem in my 36 Pontiac. Are your bushings loose? Is this pump greased? Lack of grease could have an effect if so. If it's an oiled pump, I don't know.

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Thanks Mihaly, I use Bill's site a lot and that was it! The 90 degree is the replacement.

Bloo, the old pump was tight and greased. I put a new reman on it this last go around. I will have to try it with G05 again to confirm anything.

Thanks for the help.

Dave

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Pure water does not foam as any bubbles will quickly burst. Materials that alter the surface tension of water will stabilize bubbles resulting in foam. Soap is one that is very common. Ethylene glycol is another. Adding an anti-foam agent like silicone oil will reduce the stability of bubbles and therefore reduce foaming.


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Thanks Chipper. Will soluble oil reduce the stability of bubbles?

Thanks

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It depends some on the formula for the soluble oil but, generally the stability of bubbles (foam) is slightly greater than pure water and much less than most glycol based coolants. However, soluble oils produce a film on hot surfaces that inhibit the transfer of heat. It takes measuring the actual metal temperatures in the engine to determine the significance of the loss (results in hotter metal). In some cases the temperature of the coolant is lower causing people to think it is cooling better which is exactly the opposite. THE CRITICAL TEMPERATURE IS THE COMBUSTION CHAMBER METAL NOT THE TEMPERATURE OF THE COOLANT. Coolant temperature is only a rough indicator of the heat removed from the engine.


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Thanks Chipper. It is cooling really well and seems even cooler with the four blade fan. The four blade seems a littler noisier but not bad.

I will check the temp near the plugs before and after adding the soluble oil to see what happens.

Dave

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Hello Dave39MD,
There is a lot of discussion about foam in engine coolant, so I did a Google search asking: 'silicone oil for reducing bubbles in engine coolant'. A response by- www.dow.com 'troubleshoot coolant foaming in six simple steps'. It might be of help to your issues.

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