Thanks Dieseldog, I have a 25 year old car that is virtually rust free with all the undercoating intact, and my problem disappeared entirely when I cleaned out the drain holes in front. I am very aware of the trunk drain holes too since a couple of months ago, I lost the vent hose connection to the gas tank and spilled gas into the trunk which became evident as gasoline dripped out of those drain holes.

Olof, best of luck. Maybe doing some poking with a screwdriver will reveal if the drain channels are painted over.

I got down in the forbidden area again. This time I flushed it with mega-compressed air, plus I managed to clear some mud or whatever with my bare hands. Lot of stuff coming out that could have blocked the drain, but it is till leaking.

I'm thinking about going drastic and cutting away the water deflector above the heater fan. Then I can design the cowl the way I like it, sealing holes that I don't like and drilling new where I prefer them. The deflector is visible on the picture below. When it's working I'll weld or rivet the deflector back in its place.

Another benefit from this is that I can check why the [you know what] isn't working. Yep, rust, carbs and heater fan. I definitely have a Mercedes.

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I saw an interesing accessory that might be of interest to owners of Mercedes and other vintage vehicles that have rusting and leaking cowl vents. A friend has a clear, flat, plexiglas/plastic cover fastened to the cowl vent opening on her '65 Ford Mustang to keep leaves, water and bird dumpings out of her cowl. It's fastened with little stainless hooks that grip the cowl vent 'ribs' and has little stainless thumbscrews to tighten it down. There is some kind of foam gasket as well. She got this from some Mustang supplier but it looks like something that could be home-made by someone handy. Of course, it would prevent the heating/vent system from working, but it's easily removed. Those of us that seldom drive our cars in winter, but are forced to keep them outdoors, could benefit from something like this. I wish I'd seen this device many years ago, before the cowl area rotted away on my '67 Sunbeam Alpine.

Happy Motoring, Mark

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DrDKW