Sometimes a "new" green idea is actually just the way we used to do things, before disposability and convenience became primary consumer values.

Consider the "cartridge filter" that GM touts on the Ecotec engines fitted to its new 2011 Chevrolet Cruze.

Instead of a one-piece metal cannister that's removed and tossed out every time the oil is changed, Chevrolet has built the filter housing into the engine block itself.

This allows just the pleated paper element to be replaced, which is undeniably less wasteful: no metal tossed in the garbage can, just oily paper (and some rubber).

GM has used this same design on Ecotec engines for a few years, in their 2.0-, 2.2-, and 2.4-liter sizes. Now it's being extended down to the 1.4-liter and 1.8-liter sizes that will be offered in the 2011 Cruze compact sedan.

But anyone who's owned an old British car will probably find this uproariously funny--though they may also have painful memories of being sprayed with used oil during frequent changes.

GM's "new" cartridge filter, you see, is hardly a new idea. It's a design that most automakers, even Chevrolet itself, used before the advent of the screw-on filter.

2011 Chevrolet Cruze preview

2011 Chevrolet Cruze preview

1969 MGB roadster

1969 MGB roadster

MGB roadster

MGB roadster

In fact, virtually every British car built through the late Sixties had this exact arrangement, albeit the paper cartridge was housed in a cannister than hung off the side of the engine block.

This arrangement wasn't nearly as tidy as the Cruze's filter sounds, though.

On British cars, the cannister was full of used oil, so you had to put a tub underneath and keep out of the way to avoid a messy shower of oil as you loosened the nut that held it together--and try not to drop the cannister into the tub, which would splash everything around you.

Certain MGBs were particularly evil: Their cannister was mounted upside down, to fit the large, heavy, and not-all-that-powerful 1.8-liter "B" series engine between the frame rails. Do-it-yourself oil changers were guaranteed to make a mess.

As soon as you started to unscrew the cannister bolt, oil gushed out from the seal between the cannister and the base it sat in. At least with the cannister hanging down, if you were deft you could neatly remove it without spilling its contents.

Yes, we agree, General Motors gets green points for using replaceable filters to reduce solid waste. But as they say, Everything old is new again.

[General Motors; MGB photos courtesy of Rick Feibusch]