[QUOTE=PanzerSD;1278455]
With my alternator getting wet like that, if it's not charging while it's wet, is that a sign of a faulty alternator? can most "in tune" alternators withstand some water?
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As you know, the alternator has a fan located directly behind the pulley. Contrary to appearance, the fan is designed to pull air from behind the alternator, suck it through the diodes and windings, and out through the front of the case. There are two reasons for this. First, it's most important to keep the diodes cool, and they are located at the very back of the case. The second is that it's important to keep the brushes and slip rings dry to prevent shorts, and rear to front air flow keeps water from entering the front of the case. The squealing you hear is the belt slipping, and the slipping belt is enough to lower output to the point that the lights come on.

But water on the passenger side could be coming from elsewhere:

http://www.coolcatcorp.com/190Restoration/Mercedes44.jpg

I had the same issue with my '83 240D. It was a rust hole behind the battery. Water would run down the windshield, down the firewall, and through the hole. I fixed it with miracle paint and fiberglass.

Pull your battery and take a look.

Same issue on my 84 300TD. It was the rust hole under the battery. Remove the rust, wire brush everything, treat with rust converter and triple coat with primer and paint, let dry for three days and then fiberglass it all closed then paint again. Dry as a desert now.

This can happen were leaks are apparent but no real answer to were it came from or how water seeped into the conpartment is found .If parking in frt of a garage or carport where the roofline flows directly onto the windshield lower cowl area ,the overflow makes its way into the car.Car engineers allow for the cars movement to push water off this area or dont warrant direct water to hit at force when heavy rain is present but a sitting car can find a wet floor as a result.My parents cars were found to be ok after rattling around why it didnt happen when a water hose would produce no leaks ,that is until we backed them into position with no more problems.

Look for Permatex "flowable silicone RTV" at auto parts. I haven't noticed any water on the passenger mat of my 1985 300D this winter and we have had record rains and always outside. Before using this, the passenger mat would become soaked from a drip from above. Long before, I replaced the foam AC drain hose w/ a dishwasher adapter hose.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Same issue here. The seals on the sunroof shot. (even though drains clear and free water still pouring into cab. also, when raining, if you went down a hill you got a nice pouring of water in your lap. Used clear silicon to do a temp sealing of the sunroof until I get new seals for it. But I also had the small hole under battery issue that I repaired a while back. For my hole I used treated any rust around hold with phosphoric acid and then used Metal version of JB weld, primed and painted. Check this weekend and it still looks as good as the day I did the repair! 1985 Euro 300TDT giving it some love thread... shows the repair when I did it.

Cmon' guys, real electrical tape is the ticket. The $3/roll stuff, not the HF junk. It goes on easy and will come off with little to no residue.

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment