Lower radiator hose blew off today

[Keith R.]

So, I pulled the water pump to fix a leak at the upper driver side bolt and correct some configuration issues at the same time. I repainted the front motor mount brace and the water pump. Used Hylomar Blue non-setting gasket sealant on the upper and lower radiator hose and heater hose and put it all back together. After 24 hours, I refilled the radiator and started her up. Ran fine up to temperature without any leaks so I thought I was golden until I shut her off and the coolant pressure built up. All of a sudden, there's a massive coolant explosion rivaling Old Faithful! Found that the lower radiator hose slipped off the water pump.

I've gone through all the threads relating to this and see that I probably should not have painted the neck of the pump as the paint and slippery nature of the coolant can cause the hose to come off. (I had no previous problem with this happening). I plan on removing the paint from the neck of the pump and reassembling it but before I do so, I wonder if any of you have any further suggestions to keep this from happening a second time?

[Richard M.]

Re: Lower radiator hose blew off today

Keith,

I wouldn't think Hylomar is the ideal sealer for hoses. I've used it on Jag V12 engine builds in the past and it was recommended for specific areas like tappet blocks to heads etc where you need a very thin layer of sealant, but non hardening.

Some info HERE when like your WP hose blow out, which happened to a friend's '60 I worked on. Engine had internal issues which made the problem worse but got me thinking about those lower WP outlets. I think whether or not they're painted, by design there's no rib and prone to this oddity.

Every WP hose I install I use Permatex gasket sealer, the brown stuff with the brush in the can. #2 works also. It's slippery enough to help install then acts like glue on the lower WP outlet. It make it harder to remove the hose in the future but usually cut the old hose as it's being replaced anyways.

I also use the Permatex on the heater hoses on the control valve in the cabin. Insurance to keep passengers feet cool and dry.

Rich

[Michael H.]

Re: Lower radiator hose blew off today

Did you check your radiator cap maybe it's not working correctly like not releasing pressure like it should.

Mike

[Alan D.]

Re: Lower radiator hose blew off today

Gone through that problem, too. Used some Indian Head Gasket Shellac Compound (the brown stuff), a recommended solution from the old timers with the Model T's & A's
It remains soft, never a problem since. So if nothing else is wrong try some.

[Terry D.]

Re: Lower radiator hose blew off today

Maybe replace clamps, they could be weaker from on and off too many times.

[Keith R.]

Re: Lower radiator hose blew off today

Thanks very much for the good advice. The corbin clamp was new when installed and only went on once. It is a Zip clamp vs. a Paragon clamp (which wouldn't expand enough to get it on the hose originally). The cap is new and has been tested. It functioned correctly prior to R&R'ing the pump. So, I think that I'll clean the paint off the neck of the pump and the sealant inside the hose and try the Permatex #2 on both surfaces.

[Bill M.]

Re: Lower radiator hose blew off today

Is the raised edge of the pump stil intact? Looks like a piece has eroded away.

[Keith R.]

Re: Lower radiator hose blew off today

Is the raised edge of the pump stil intact? Looks like a piece has eroded away.

To tell you the truth, I'm not sure that it was ever there. As Rich Mozzetta said, these pumps perhaps never had the ring around the neck. I've got a spare pump and will take a look at that.

[Mark E.]

Re: Lower radiator hose blew off today

Back in the day when I acquired a used car with spring style clamps, I would replace them with worm style clamps as insurance. The spring clamps are not reliably tight.

I second the Permatex #2, although the hose may need to be cut when removed.

[Keith R.]

Re: Lower radiator hose blew off today

No ring around the neck of this spare pump. I think that I'll take the advice of a local chapter member and use black RTV on the neck and inside of the hose.

[Tom E.]

Re: Lower radiator hose blew off today

Keith,
I would recommend not using RTV or any other sealant. You will get the most amount of friction from a new rubber hose and clean metal, painted or not doesn’t matter IMO. GM put millions of vehicles together this way and they did quite well.
Tom

[Edward J.]

[Mike M.]

Re: Lower radiator hose blew off today

I'd remove the lip-less pump, glass bead the outlet, then take the pump to a qualified cast iron welder to have a lip reconstruction. that is, if the pump's casting # makes it appropriate for the car and you have no other pumps that would be appropriate substitutes. mike

[Edward J.]

Re: Lower radiator hose blew off today

Keith, another opinion is use JB weld and make your own lip. Or Mikes idea will work also.

[Danny P.]

Re: Lower radiator hose blew off today

So, I pulled the water pump to fix a leak at the upper driver side bolt and correct some configuration issues at the same time. I repainted the front motor mount brace and the water pump. Used Hylomar Blue non-setting gasket sealant on the upper and lower radiator hose and heater hose and put it all back together. After 24 hours, I refilled the radiator and started her up. Ran fine up to temperature without any leaks so I thought I was golden until I shut her off and the coolant pressure built up. All of a sudden, there's a massive coolant explosion rivaling Old Faithful! Found that the lower radiator hose slipped off the water pump.

I've gone through all the threads relating to this and see that I probably should not have painted the neck of the pump as the paint and slippery nature of the coolant can cause the hose to come off. (I had no previous problem with this happening). I plan on removing the paint from the neck of the pump and reassembling it but before I do so, I wonder if any of you have any further suggestions to keep this from happening a second time?

Looking at the photos, those spring clamp type aren't best and it not holding the build up pressure, put on a good worm gear or tower clamp.