Soot on my clean hood!

[Waterloo]

I had an CM-870 in a Volvo that did that same thing. Water from the truck wash would get into the stack and pool. Start it up the next morning and it would rain soot every time. Would do the same after a very hard rain too.

And that is another thing, that water did get into my exhaust system and rotted it out from the inside. Almost killed me with carbon monoxide. Check your exhaust piping, especially under the cab. I was surprised how quickly these exhausts will rot out. This was on a new truck.