Teddy's truck lie makes no sense

Why would he say 'that thing's been there for years', when he could just shrug and 'not know'? Of course it would still be an implied lie, but at least not a useless, outright, direct lie.

Was he trying to keep Leonard from being interested in the truck and eventually finding out it was him who drove it there?

In any case, Teddy uselessly revealed that he has been in the place and knows the place more intimately than he has any reason to reveal to Lenny, so it makes no sense. Why would he let Lenny know all that? He could've just left it that he knows the place, and that's it.

Why even talk about the truck, as if he knows anything about it? Wouldn't it be more suspicious that way? What's the point of trying to make Lenny think the truck has been there for YEARS? What difference does it make how long the truck has been there? Furthermore, he's now tying himself with the truck in Lenny's viewpoint, when he absolutely didn't have to.

Why not just shrug like a normal individual and move on to something else? Why try to feed Lenny stories about the truck? It makes no sense.