The inside of my BMW E46 M3 is damp, and I want to trace the source of the moisture so I can stop it. I know of some of the common sources of damp inside these cars, for instance it's a convertible so it could be blocked drains, the membrane on the inside of the door could have a leak, and many others. The problem is tracing the source, I want to take a 'data-driven' approach.

I am thinking of getting an inexpensive two electrode moisture meter, and then mapping the moisture levels at different parts of the car, for instance front left floor, front right floor, etc. The assumption is that the area closest to the leak source will be damper than other areas, and tell me where to look. However, I'm not sure if that is a good assumption.

Is this a sensible method to track down the leak, or is there a better way to do it?

1 Answer 1


I would have a observer inside car and then with all doors and windows closed, spray all over exterior window and door openings lightly with a garden hose and see if we can see any water intrusion with this way first. This is a convertible, spray around all areas of the roof lightly, see if you find anything.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .