Water leaks into Mercedes interior

I have a low mileage, rust free 1984 Mercedes turbodiesel coupe with a major problem–water leaks into the rear passenger footwells, trunk, and drips onto my left leg when I drive in the rain.

Please help me fix this annoying problem!

Thanks, Peter

Does This Car Have An Antenna On The Left Side? Do You Have A Sunroof?

Antennae are usually on the right, but leaking antennae often allow water to run along the antenna lead (wire) and drip off at a low point. Gravity takes it from there.

Sun roofs have drain tubes in their corners that catch leaking water and drain it down roof pillars to the outside. They can clog and allow the sun roofs channel to overflow.

Heater cores can leak coolant from under the dashboard.

Air Conditioners have drains that can clog and leak condensated water from the evaporator under the dash board.

The big mystery here is that any of these leaks could hit your leg and run to footwells, but the trunk is usually higher that that. How can water hit your leg and flow uphill to the trunk? Two leaks? Look at the relationship of the footwells to the trunk area. Do you have a guess?


Thanks for your timely response.
I had been looking for a global solution, but my problem may be multicausal.
I will look at the integrity of my rear mounted antenna gasket since that’s right above where the puddle forms.
I hope when I remove the interior trim at the rear corners of the cabin, I will be able to visualize the drain system.
First off, I need to change the alternator-- letting a 25yr old car sit for several years is not good.
I appreciate your advice–anything else that comes up for you, give me a holler.

Peter, You’re Welcome.

Keep a couple of things in mind. Gravity takes the water to the lowest points, even if they are quite remote (leak in front flowing to rear) from the source of the leak(s). The water can travel under floor coverings.

Often little “trails” are left behind by water that is running down a panel, etcetera. The trail is sometimes hard to see with just a cursory glance. It often is evidenced by the absence of dust that has accumulated over the years or it could be in the form of a built up, dry residue from a recurring leak. A good flashlight could help you to see them. When any panels, trunk lining, etcetera is removed, check these areas.

With one person inside the car and another person outside the car with a hose, you could see if the person outside can move the running hose to just the right place to have water drip onto one’s leg or drip from the antenna base into the trunk (lining partially removed). Move the hose very slowly as some leaks take several moments to begin.


Again, thanks!