Radiator Question

[garys_bc]

Ok, here's my next issue.. After flushing my radiator in my 47 dodge, I have noticed a small leak in the radiator in the area above the fins. I looks like it has been soldered there before. Any suggestions? Can I re-solder it? Plumbing type solder? Someone recommended removing the radiator and having it tested. It is only one small leak, removing it seems extreme to me.

[Brendan D25]

Also look at your rad cap. It should be non pressurized. If the system gets pressurized due to using a 15lb. or so cap the top tank will crack near the bottom. If you bring your rad to a rad shop don't let them pressurize it any more than 4 or 5lbs. Good Luck, Brendan.

[garys_bc]

Ok, I am no expert at these old cars. This may seem dumb, but I have not been able to find any instructions on the web as to the best method to solder it. What solder should I use? Do I use a prop. torch or a soldering iron? Any suggestions are appreciated.

Newbie.

[Plymouthy Adams]

in all seriousness if you have no experience with repairing a radiator..it may be best to drop it off by a shop..

however..depending on the area, wattage of your iron..if you have the heat and access and 63/27 solder..go for it..if you have some good acid flux..propane torch and you can fan the area and apply some lead..

The iron would be easier for you if you have room to place the tip..torch can do some damage if you overheat the area..

[55 Fargo]

Also look at your rad cap. It should be non pressurized. If the system gets pressurized due to using a 15lb. or so cap the top tank will crack near the bottom. If you bring your rad to a rad shop don't let them pressurize it any more than 4 or 5lbs. Good Luck, Brendan.

Hi Brendan used to think the same, never put on a pressure cap on my non-pressurized rad.

One day it was either explained to me, or I suddenly realized, you cannot pressurize these rads by plopping on a pressure cap, they do not seat as the pressure type rads, plus there is an overflow line right on top of the rad, to let air or coolant out.

This of course allows air to discharge out of the rad, so it can't be pressurized.

I currently am using a 7 lb cap on my non-pressure rad, simply because I do not have a non-pressure cap that is in decent shape...............Fred

[Brendan D25]

Hi Fred, I remember the discussion on here before about the pressure caps, but a friend of mine has a P15 and the bottom left side of the top tank was leaking badly. His cap was rated at 15lbs pressure. I suggested that he change out the cap for a non-pressurized one to see what would happen and the leak is still there but not near as bad as it was. I will have to have a closer look at the rad in his car to see if it is original. You are right in what you are saying if the overflow is separate from the filler neck. Brendan.

[garbagestate 44]

I had a similar problem. I'm getting ready to start a 47 Chrysler and found that the radiator leaked where the tubes run into the upper tank. Given the thickness of the core, it was hard to say where the leak was exactly although it wasn't serious. Since a 400 dollar re core wasn't in the budget and my skill at tinning radiators is marginal at best, I went for the quick fix by using this silicone based sealer ( Dow-Corning type 832 ) I used a caulking gun to inject it directly into the honeycomb core. It was a small area and it did work but only because it's a non pressurized system. I don't know how well it would work for the long haul but in my case its good enough for the run up later this month. ( It's going to be a long time before I'm actually driving it ) Good Luck, John

[BobT-47P15]

A local radiator shop cleaned and resoldered one for me recently for $60...not

too bad actually.