The drain under the battery tray on my 85 was plugged solid with fine black silt, probably a mix of decomposed leaves and dirt. The opposite side also has a drain and is also plugged! It is hard to get access unless the ARV valve/ relay bracket is removed. I cleaned out both drains for now but a long term solution is needed. The problem is that everything drains into the hood hinge cavities (including the channel above the firewall, which then drains into a depression (with a drain) under the battery tray. The opposing drain on the driver's side can be easily inspected but the one under the battery cannot without taking the battery out, which is no small task.

The leaves come in via the gap between the hood and the fenders and hood /firewall channel. A seal of that gap above the fire wall (blocking the channel) and between fender and hood in the hood hinge areas would stop the leaves IMO.

Vinyl weatherstripping, the type with a hollow tube may work if it can be attached securely to the body. A mesh or screen would be difficult to implement due the the hinge arms.

As a test, I will tape the gaps in the areas mentioned, wait a week and check under the hood. I can afford to do this since the 300D is not my daily driver.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked