Just purchased a used 03 F150 Supercrew. I noticed that the frame looked really dirty. I took my finger and scraped away the dirt and underneath it was grease or oil. I crawled under the truck and looked at the entire frame, it was completely coated with dirt. However, nothing else under the truck is like this. At first I thought maybe the previous owner had driven through oil, but since it is just the frame, I was wondering if this could be a factory, or aftermarket, applied treatment to the frame? Any thoughts?

 

I believe all F-150s come with greased frames straight from factory. It's black and nasty as hell but I'm sure it's there for a reason, probably to prevent rust.

 

I second the thought that it's probbaly an undercoating treatment to the frame to keep it from rusting applied at the factory. It's very greasy and very nasty, but hey, oil and water don't mix so if oil's there, then water won't (thus rust it will not )

TonyPTX

 

It's so nasty that rust and people avoid it.