BrianK

Why would there be any more carbon monoxide in the cowl area than anywhere else. The exhaust is out the back. Unless there was an exhaust leak and you'd probably get that fixed.
Just another note on a rubber drain problem - and not to hijack the topic, but the same problem exists on fridges with lower freezers that get ice build up in the freezer. There is a rubber 'duckbill' drain accessible from the lower rear access panel that gets plugged with little things and causes water to back up into the freezer. The water is generated during the defrost cycle and is supposed to drain into a pan by the compressor. I pulled the rubber duckbill off, cleaned the ice buildup and no problems since. Same ****, Different Day LOL.
A good idea to take out the rubber cowl.

tradosaurus

Hmmmm...I suppose if there were a leak on the exhaust manifold. I never thought of that.