Radiator Drain Plug Fouled

mgm60

Member
Today I removed one of my head bolts that was weeping a little coolant also installed new temp sending units in both heads. When I went to drain some coolant my project went South.

This 36 Coupe is new to me so I was surprised to see it did not have a drain ****. In its place is a brass fitting that holds the temp sensor for the fan. Sensor was too long for me to remove without breaking the lead but on the other side was a bolt so I thought ok I’ll remove that and install a drain ****. Bad news. Someone previously soldered it so now the insert that holds bolt is broken loose and I’m draining coolant with no clear way to reseal.
Any suggestions? Can I just clean this up and resolder? Would hate to have to remove this radiator. See the pictures.
 

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Today I removed one of my head bolts that was weeping a little coolant also installed new temp sending units in both heads. When I went to drain some coolant my project went South.

This 36 Coupe is new to me so I was surprised to see it did not have a drain ****. In its place is a brass fitting that holds the temp sensor for the fan. Sensor was too long for me to remove without breaking the lead but on the other side was a bolt so I thought ok I’ll remove that and install a drain ****. Bad news. Someone previously soldered it so now the insert that holds bolt is broken loose and I’m draining coolant with no clear way to reseal.
Any suggestions? Can I just clean this up and resolder? Would hate to have to remove this radiator. See the pictures.
588878


588879
 
I would find a old school radiator shop and have that plug sealed and have them install a petcock as original.
It will pay for itself in the long run.
 
Looks like you will have to cut out the cracked metal strap surrounding the drain and repair the damaged underneath the strap. Then replace the strap with a new piece of metal welded in place.
Won't be able to tell until you pull radiator and take it apart.
 
Thanks for the suggestions. To clarify the situation, the radiator did not crack underneath the reinforcing metal strap. The threaded insert that holds the bolt broke loose from the radiator housing where it had previously been soldered. The coolant drained from around the threaded insert.
 
That area looks like it would be difficult to clean and solder. Would it be possible to drill out or carefully grind out the threaded insert and install another insert using JB Weld (or stronger) Epoxy. Then install a threaded petcock. If you have a lathe you could make a new insert out of brass or copper OR you might actually find a suitable brass fitting at Lowes or Home depot that you could modify and use.
Here's some radiator epoxy info: https://www.google.com/search?q=wha...CAQ&sourceid=chrome&source=chrome.ob&ie=UTF-8
That's a repair that can easily turn into a project.
 
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What are my odds for success if I aggressively clean this area down to bare metal and use JB Weld High temp liquid epoxy? I could create a dam and fill that whole cavity between the reinforcing metal strap and the threaded insert and let it harden for a couple of days. Worse case, that fails and I'm removing the radiator.
 
I would not gob a bunch of JB Weld on there, its just harder t fix proper then.

There are still real radiator shops around, you need to do a search. They will remove the bottom bracket, install a new threaded boss for the drain, replace the bracket and anything else thats loose
 
Why are you asking here? It sounds like you have decided that it' s good way to go and you're going ahead with it.

Get off the computer and do it; that's what we did back in the day. It worked most of the time, too. I made a "temporary" fix to a drivers side vent window regulator on my '67 Corvette about 25 years ago with JB Weld that worked great. It still does. Every time I drive the car, I open that vent window. Every once in a while, a thought runs through my mind that says I should re-do the repair. Everything else within me says : "If it ain't broke, don't fix it".
 
How about a small rubber expansion plug . Or what Ive used in situations like this are tire fill valve stems , the kind used on custom , mag rims with thick orings and trheaded nuts to secure. Not sure they would fit you hole . I think they are 5/8” . It would require you to remove the spinning plug .
 
Naapa has them under screw together tire valve stems part numbers nth 90432 4.39 each
Cancel this idea . Mine was on the near the lower hose where I could get my wire in there and feed the valve through the hole then tighten it
 
As others have said....remove the radiator, get it professionally cleaned and repaired. That sending unit? Should that be installed 90 degrees to its current installation? That tubing does not look good bending around as it is. Secure it so it does not rattle and break
 
Abandoned the solder job as access is impossible and started the radiator removal this weekend. Pulled the lower and upper hoses, removed the alternator and the most stressful part took the hood off. The hood was a three man job but we managed to get it off without any mishaps. Here are a few pictures. I'll keep adding updates here with pictures in case anybody needs them for reference.
 

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