"How I Do It"

Finding the Source of a Leak

Finding the source of a leak can be a frustrating experience. The technique described here will help you track down the source of a fluid leak, such as antifreeze, engine oil, or transmission fluid.



You could also use talcum powder or corn starch. To illustrate, the following photos are of a leaking transmission on a 65 Chrysler. I had chased this leak for a while with no success.....probably because there are too many things to tighten and too many things with the potential to leak. Then I thought of the powder.

I cleaned the transmission with spray solvent, let it dry, and applied baby powder. Generously. Everywhere. I let it sit for a week. When I came back, there was a definite trail of fluid in the powder.

A plumber once told me: "There are two things you need to know. 1) Water runs down hill. 2) Paydays are Friday." So I followed the leak trail in the powder back to its highest point. It turns out my forward cooler line was leaking at the fitting on the transmission case. It was a 15 minute fix. Well, it would have been a 15 minute fix if I had used the powder to begin with, but live and learn.

The passenger side of the transmission case with powder. No leaks here.

The park pawl assembly showing a slight leak but no leaks from the park cable.
Also, no leaks at the pan.

The rear cooler line, no leaks.
The powder shows what is leaking
and equally important, what is not leaking.

The front cooler line area......a problem here.

Closer inspection showed the leak comes from this fitting.