Leakage in Radiator

[rainer]

Hello.

Today I checked my Lizzy as preparation for my tomorrow trip. I was wondering that a lot of water was missing. I filled it up and then I got the idea to have a look on the back side of the radiator... and I saw one pipe appearing wet.
It is a radiator of a Touring 1915, brass.

Leaking pipe (marked)

The marked pipe is definitely not dry. I touched it with a piece of toilet paper and it soaked up a little bit of water.

Luckily this is the back-most pipe, and I can only hope that the water is not coming from an inner pipe. At least, the front of the radiator is dry.

This radiator is one with round pipes and chances are good that it is an original one. It has a brass plate soldered on right side of upper chamber, showing this:

Brass plate on radiator

My questions:
At the moment coolant loss is not so dramatic, so I will be able to drive it tomorrow and next time, but this needs to be repaired. Sadly I have no experience in that, so I better ask first before doing something stupid.
Leakage must me very minimal, water does not drop on my garage floor. I watched the radiator after filling it above the perforated metal sheet in its upper chamber, so there is everything filled up. The marked rib (where the joint is brown) is the last wet one, all ribs below are dry since more than one hour.

• To find the exact point of leakage, I will have to submerge the entire radiator in water and set it under slight pressure. This is a job for winter time, I don't think that the leakage will get worse so quickly.
• What are well working methods for sealing? As this appears to be the back most pipe, access should be good. The leakage can be between upper chamber and pipe, or somewhere along the pipe then. Is soldering the only way (this will require a specialist and perhaps partially removing a rib), or are there also other options, i.e. applying some special sealant/glue from outside? My concern is the relatively high temperature, but it is helpful that the cooling system has no pressure. If it wouldn't be so hot, I would think about using some drops of Epoxy, but at almost 100°C I am not so sure any more.
• Having a look on the shape of upper radiator ribs, it seems there was some repair in the past, otherwise they would be straight.

Please, share your experience with me. Any helpful information is welcome.

Rainer

[Norman Kling]

I would recommend that you drive the car hard and uphill if there is one near you to see how it cools. The old radiators can be clean but still not cool very well. When you are sure it is still cooling sufficiently to keep the car running in hot weather, then find a radiator shop which can work with brass radiators to do the work.
Norm

[rainer]

Hello, Norman.

Last weekend I did a 100km trip at very sunny weather and temperature of 32°C. There were some steep hills, one steep enough to need low gear with max power. The motometer climbed close to upper end of the hole, but the car did not start boiling. So I think the radiator is working well.

Flat tube radiators are for sure more efficient, but I don't want such modifications. Also, a new radiator is some thousand USD, a repair is for sure lots cheaper.

So I will start looking for a radiator repair company.

[Professor Fate]

I used this stuff with great success in my '23 touring.
Did about 800 miles in a whole driving season, then pulled it for repair in winter.
I recommend you add it in 1/2 of the bottle increments. Run the car after adding.

[rainer]

Hello,
will this stuff leave residue on all surfaces? I am a bit scared because this would reduce radiator efficiency. If it only clogs the leaks, it is fine.

Only to give an idea on how intense the leakage is:
Yesterday, when I started this thread, I filled up water. Today the pipe is still wet in same section. Water didn't spread out on radiator ribs and there are no drops on garage floor, so it can evaporate in same speed as it leaks.

Rainer

I used this stuff with great success in my '23 touring.
Did about 800 miles in a whole driving season, then pulled it for repair in winter.
I recommend you add it in 1/2 of the bottle increments. Run the car after adding.

[Professor Fate]

I did not find that product to increase operational coolant temps. I added maybe 2/3 of a bottle, 1/3 at a time, and the leak stopped for good. My idea was to only add enuff to get the job done. It's a thick concoction with little "rabbit turd" pellets that dissolve and block leaks.
I had a couple of pinholes in round tubes. Tubes were eventually cut out and soldered. But this stuff was slick and fixed me right up. I kept and still do a bottle to get me home in my roadkit. Rabbit turds to the rescue!

[Eric Sole]

Hahaha, the rabbit turds did the trick, but it doesn't hurt anything to have that water pump lubricant either. Oops, don't want to start a battle here.

Some people put leak repair products in their cooling system as a preventative. I don't normally condone this but I have on some occasions put a small amount of stop leak in a system that just seeps and the stop-leak takes care of it without any secondary problems such as plugging of tubes, etc.