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Anyone have ideas?
m
Not any Sprinter specific ideas, but some experience. The Dodge vans used the fender cavity as part of the intake air duct system for the HVAC. I found that leaves would accumulate, get wet, rot, and then have a bad odor which was pulled into the van. In that case I actually drilled access holes at the inside bottom of the fender cavity with a hole saw so I could hook the debris out. Those holes also allowed the leaves to dry out if any did get in there again.
Come to think of it there are some drain holes in the Sprinter which are known to plug up. On my T1N there is one on each side below the windshield. There are also some under the vehicle. I use a stiff cable tie to clear the drains. I think it is less scratchy than a piece of iron wire.
I suppose one of those Home Depot spiky sink drain hair/clog removers might work too.
A search from the blue bar may get you some specific info about the drain/weep holes. I remember it being discussed here before.
If the condensate drain on your evaporator is plugged you may be getting some funky water building up in that catch pan. Have you cleaned or replaced your cabin filter lately? It may be due. Good luck. vic