Rain water in engine compartment - normal?

[instarmercedes]

I wished I had found this forum years ago! I've learned a lot in just a few short days.

I'm having a problem with my 1993 300TE (131K) and fouling out sparkplugs during rain or while washing the car and thought I'd ask the experts their opinion on which way to go. I've always had the car meticulously maintained with all the required maintence by my local mechanic (there is no dealer in my area).

I'm not a mechanic, so I probably will write too much, but I want to give as much information as possible in case someone has an idea of what I should try.

I left the car with my mechanic for a week to try and isolate the problem and so far he hasn't nailed it down. What I've noticed is there is a lot of water collecting on the rear part of the engine on both sides (behind the large gasket that sections off the battery and fuse box) when I run a waterhose across the hood and down the windshield. It may be a coincidence, but the problem started the morning after a freak spring storm on Mother's Day when we experienced 60+ mile an hour winds and I had left my car in the driveway. The gasket that runs along the bottom of the windshield has been somewhat loose for a while and now is pretty well hanging by a thread.

My question: would replacing the windshield gasket solve the problem or is water in that part of the engine normal? I've read on line about an instance where a faulty manifold gasket was letting water in and fouling the sparkplugs during rain, but my mechanic checked that and said it was sound.

Thanks and any suggestions appreciated.