![Image](http://farmallcub.com/images/ht501/cooling/suspect.jpg)
So I decided to try a little experiment. I drained the radiator, and set the pressure regulator on my compressor to about 5 pounds.
![Image](http://farmallcub.com/images/ht501/cooling/gauges.jpg)
I then put an open fitting on the hose and inserted it into the top of the radiator and stuffed a wet rag around it to make a loose seal.
![Image](http://farmallcub.com/images/ht501/cooling/filler.jpg)
I turnd the air on and sprayed it with a mixture of 20% dish soap and water in a hand spray bottle.
NOTHING!
Maybe the leak is not where I thought it was.
OOPS, forgot to put the drain plug back in.
Replaced it and look at the bubbles.
![Image](http://farmallcub.com/images/ht501/cooling/bubbles.jpg)
With this set up it can be soldered and retested without refilling.