6 inches of water in my trunk...
 

i have a 116 300sd and I have found that on the right side of the trunk after a good rain will have up to 6 inches of water in it. I will check the carpet on the sides and I can't find any of it that is wet. The only wet part is the bottom where the water is.....I haven't noticed any leaking from the rear window. the rubber around the trunk has been cleaned and syliconed. Got any ideas?

Usually the water seeps under the bottom of the rear window gasket, then drools down into the trunk...its hard to actually see it happening, you just find the results (lots of water in trunk). Rear window seal probably needs to be replaced. I always thought the trunk troughs at the side had a little drain plug in them....maybe its plugged?

Check the gasket around the fuel filler neck and the drain in the filler compartment. If the drain is plugged, water entering the compartment could slide down the outside of the filler pipe and drip off into the trunk where it would end up in the well on the right side.

There should also be a drain at the bottom of the well; it may also be plugged.

The above assumes your 116 is similar to my 123.

Finding the source of the leak
 

If the W116 is set up is anything like the W126, it's also possible the water drained into the trunk through a taillight seal.

Can you have someone get inside the trunk of the car, with a flashlight or something, then the trunk is closed (By you) and then tney look to see where the water is coming in, as you spray all over the trunk with a strong garden hose?

Just a thought

I had the same problem on my 126. If you open the door to the fuel fill area you will see a hole about a 1/2" or so in diameter that allows rain water and spilled fuel to drain out of that small compartment. On mine that hose that connects to that drain had come disconnected. I found the problem after removing the carpeted panels inside the trunk. I reattached the hose and put a tie wrap on it to hold it in place. So far, so good:)

there are quite a lot of people I could think of that I would love to put in the back of the trunk...:behead:

I will check all of that
 

thanks for the answers. I will take a look at it this afternoon and see if I can get the lake out of my benz....

I had the same water problem in my w116 300sd.
First I put my reluctant daughter in the trunk with a flashlight; and made rain with the garden hose. She made a full report of "rain from everywhere was coming in!":eek: "Please don't make me do this again!":mad:

I had to do ALL:eek: of the things above to stop the water leaks; I sealed the fuel neck gasket & unclogged the drain hose; sealed the rear window gasket; tightened & sealed the taillight housings; cleaned the trunk lid gasket & lid mating surface and the leaves, dirt & garbage in the gasket trough. And unclog the well drains.

After all this; I got in the trunk & let my daughter make it rain.
Dry as a bone!:D

Now of course this didn't fix all the leaks into the passenger compartment...but that is a completly different story we'll save for another night.

cdplayer
 

I too have a W126 with an elusive leak into the trunk. Mine however was leaking from the passenger rain gutter!!! Looking carefully as the gutter angled down from the roof top, I noticed the rubber gasket between the gutter and the frame did not match up just right. A bead of silicone about two feet long solved that pesky damp trunk fender well.:wacko:

More leaks
 

Another source of leaks is the taillight lenses themselves. One of mine had several cracks, either age related or 'tapped' in a parking lot (or both). Water leaked in and ran into the well of the right side. I sealed up the leaks with silicone sealer.