Pontiac renovations, part 23.

August rolled around again, and as it is wont to do, has been warm.

Warm in the garage

Having spoken to a radiator shop and been quoted a significantly higher price than I could afford for repair, I decided to set about and attempt a repair on my radiator myself.

Filler neck

The filler neck had what looked like some sort of putty or mastic spread all around it in a messy fashion.


I pried at it a little with a screwdriver and a large chunk fell off, showing it to actually be lead solder. Whoever put it on did it badly.

Filler neck removed

I decided to cut my losses, and while holding the cap in my big pliers, I heated it up with my gas torch. It popped off with relative ease, showing a lot of dirt where it had split away from the top tank, and was being held in place around about one fifth of it’s circumference.

Cleaned with wire brush

I used a steel wire wheel to clean both the top of the tank and the filler neck. I then added soldering flux, heated them both and tinned them by adding solder to each face, ensuring good adhesion.

Filler cap soldered in place

I then lined the two pieces up and heated them so the solder flowed and melted together. Hopefully a permanent repair.

Big gas flame

The radiator had been leaking along the seam between the fins and the top tank. I cleaned it up and attempted to solder it up with my gas torch, which proved to have a flame too broad and too hot to easily work with.

Soldering with big flame

I was able to make a good seal, but it wasn’t the tidiest of work. I went to the store and bought a torch with a much tighter flame pattern, adjustable temperature also.

Small torch

The tighter flame allowed me to control the heat better, and so I soldered up the rest of the seam.

Seam soldering complete

This method allowed me to improve my technique and make a much more tidy repair.

Pressure testing

I built a rather Heath-Robinson testing rig, consisting of the garden hose and some duct tape.


With the seam no longer leaking, the pressure testing identified a small crack in the top tank.


I cleaned the area around the crack mechanically with a wire wheel, then chemically with acid flux.


I soldered the crack up and tested it again. This time it didn’t leak.

A bit of black paint

I cleaned the metal down of old flaking paint and gave it a coat of semi gloss black. I ran out of paint, will continue the rest with a new can.

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