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MG TD TF 1500 - Rodding a 51 radiator

With my engine out for a rebuild, I had time to work on other systems, so I'm rebuilding the water pump and the oil pump. I also decided to check the radiator. Out of the car, I noticed that the side brackets which hold the main crossbar were cracked on both sides, so I needed to fix that. To remove the side brackets, they have to be desoldered from the top radiator tank.
Once I had desoldered them, I had the radiator completely free, so I thought I should have someone really go through it. After talking to a local radiator shop, I decided to go ahead and desolder it myself, thinking that if worse came to worse, I could always take it in to them to fix my screwups. So I carefully desoldered the top tank and freed it.
The first thing I learned was that the key to taking a MG radiator apart yourself is the central dimple on the top of the tank. It appears to have no purpose, but in fact, it has a hole in it which has been filled with solder, and the purpose is to give the tank more "structure" to hold it together. It is soldered to the big bronze pipe which connects to the thermostat via a rubber pipe.
If you try to separate the top tank just by desoldering the sides completely, it still won't come apart... you have to desolder that central dimple. When you do that, the tank is then easy to desolder as it pretty much pops open.
So for anyone looking to do this themselves, remember to desolder that top dimple first till the tank top pops up, then you can desolder the sides easily.
Once I had the tank open, it was time to look at the inner core, which consists of three rows of narrow tubes, a total of 62 of them in all. Mine were not terrible, but on both edges several of the tubes were completely clogged, and cleaning all of them is certainly a good idea. I started by thoroughly brushing the tops so I could see what I was doing, and cleaning it as much as I could.
The process of cleaning the tubes themselves is called "rodding" and I started by fishing a wire through the first few, but stopped because I realized that the wire was soft wire , which might easily break off in the tube, which I definitely did not want to happen.
As often happens when I stop and put a project aside to think about it, the answer came to me at night and I woke up realizing I had the perfect "rodding" tool... an electrician's fishing tool, which is a roll of about 25 feet of thin spring steel about 1/32 thick and 1/4 wide. I cut off the end, which has a spiral spring on it, and filed the end smooth and round, and presto it was the perfect tool to slide into those tubes and clean them out. Quick too; a couple of passes on each one cleared out everything and brought dust out in the process.
I then flushed it with water, pouring into the top and letting the rusty water flow out the bottom. This made sure that I hadn't left much residue in the tubes.
Two tubes on the right side were so heavily occluded that I had to use a screwdriver to open them up before getting the rod in. In the process I broke the solder line (or else they had been deliberately soldered shut because they leaked when being installed - I'll never know - so that when I came to put it all back together I had a leak.
I soldered the top tank shut again and water tested it and discovered the leak, so, time to desolder again.
This time, I was able to track the leak down and could see it was coming from the top of the tubes, and I could see two lines of metal, (the tube itself, and the punched hole where the tube fitted in) so clearly the solder was gone. All the other tubes had no visible lines as the soldering process smoothes them over and makes them invisble.
I cleaned it up, filing and sanding around the edges till I had bright copper, then used muriatic acid to get off all remaining oil and dirt, then soldered carefully all around each tube at the top.
Once I was satisified I had fixed those leaks, I resoldered the top.
The process is the same in reverse; the key is to solder shut that dimple using a clamp to squeeze the top back to where it touches the bronze pipe cove, and solder it well. This puts pressure on the whole tank to fit neatly back into the lip of the base nicely. Once it's done, soldering the edge is pretty easy; it just takes a LOT of solder (I was amazed how much came out in the process of desoldering - clearly they used a lot when building it) to make sure that it's fully filled all around the lip.
Then I took it down to the radiator shop where they gave me a free pressure test at 15 psi and presto, it passed!
Another project complete and the satisfaction of knowing another part of this old car inside and out.
The downside of course, is that if anything goes wrong later I have nobody to blame but myself!
A last note: I had removed the tag on the back of the radiator where it was soldered to the crossfins, and when I replaced it, I resoldered it on a point where it will sit underneath the big crossbar - thus adding another square inch of working radiating surface to the radiator and increasing efficiency by a tiny percent!
Geoffrey M Baker

Here's a picture of the top removed. The silver circle shows the "dimple" that is the key to successfully desoldering the tank

Geoffrey M Baker

Here's a picture of all the tubes now accessible for "rodding"

Geoffrey M Baker

Here's a picture of the small brass plate I moved so it is now under the main rear crossbar.

Geoffrey M Baker

Hopes this helps anyone else with cooling system problems who may want to try a DIY approach... I didn't do this to save money (though it probably would have cost me $150-200 to have someone do it for me); instead my goal was the peace of mind knowing it was done and I think done right... my radiator should now operate at something close to the original factory specs!
Geoffrey M Baker

Hopes this helps anyone else with cooling system problems who may want to try a DIY approach... I didn't do this to save money (though it probably would have cost me $150-200 to have someone do it for me; instead my goal was the peace of mind knowing it was done and I think done right... my radiator should now operate at something close to the original factory specs!
Geoffrey M Baker

smart. good job there Geoff
mog

As mentioned in my tread on correcting the alignment of the top radiator pipe, I cut off the top of the pipe (ie the section that is soldered to the top if the tank) so I could align the pipe correctly and had a 2c coin soldered inside the hole and the hole filled with solder.

Stuart Duncan 1953 TD

Stuart, I'm sure that was a necessary fix for you given your problem; however for most people I would strongly recommend against doing that unless absolutely necessary; the solder connection between the pipe and the top of the tank helps create the integrity of the tank itself. It makes the tank stronger and the bronze pipe section stronger if it is all soldered together. Without it, the bottom of the tank will flex (and possibly crack) around the pipe if put under strain.
Geoffrey M Baker

Very nice write-up Geoffrey! Thanks for posting.
Gene Gillam

Very nice write-up Geoffrey! Thanks for posting.
Gene Gillam

And here is a picture of the radiator, complete and reassembled. I ended up painting it black rather than trying to clean up the brass.
As I said at the start of this thread, I ended up rodding the radiator because when I looked at the radiator frame, I noticed there were cracks on both sides, and to fix those cracks by welding, I had to desolder the frame from the tank. This requires desoldering the 'straps' that are soldered to the top of the top tank and desoldering the right angle frame that is soldered to the bottom of the top tank.
It was worth doing for this alone, because it allowed me to spot weld and repair the cracks, and also I then removed the bottom bracket (soldered to the bottom tank in six places) and cleaned it completely. Between the tank and the bracket, it was filled with crud, and what I believe was the remains of some felt-like cloth material strip, possibly used to reduce vibration. It was pretty rusty in the places where the moisture remained in the organic material sandwiched between the two pieces, and taking it off allowed me to completely clean it out, wire brush it and remove the rust and repaint it. I put a piece of inner tube in between the tank and the bottom frame, as a replacement for the cloth and to reduce wear and vibration. All good for my peace of mind going forward!
Now good as new and ready to go... back to all the other projects!

Geoffrey M Baker

I've said it before and I'll say it again. Most cooling problems are due to accumulated crud. With a properly flowing radiator and block, the cooling system will do its job in any climate. Your engine should run completely cool now Geoffrey!

Do keep in mind also that the placement of the various brackets are critical to your grill shell fitting properly. Re-using the original core will make it far easier, but every bit the brackets move, also moves the shell out of alignment with the bodywork.
Steve Simmons

Yes, I was careful to try to fit everything back exactly where it was originally. We'll see when it comes to the final assembly how well I did!
I do expect a massive improvement; between the clogged radiator (I would guess it was running at no better than 60% efficiency) and the completely unclogged engine block (with improved flow via drilling the extra hole and opening up the water entrance and exit holes in the block as per the "cooling system bottleneck" thread) I think I'll see a big improvement.
Geoffrey M Baker

This thread was discussed between 14/04/2015 and 16/04/2015

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