Join Date: Dec 2014Location: Tucson, AZPosts: 1,478

I'm biased because I have a oil catch can installed. It does collect oil that would otherwise get sucked into the air intake manifold. I like the idea of the oil not getting sucked into intake manifold ... so to me it's worthwhile.

Some of the new cars with direct fuel injection are coming with oil catch cans because the injectors inject fuel directly into the cylinders rather than injecting fuel with the air at the intake valves. With direct injection the intake valves don't get washed with detergent gasoline and the oil that gets sucked into the air intake manifold bakes onto the intake valves. This requires service to remove the baked oil (on some cars it's frequent and expensive) or you risk poor performance, poor MPG or possible engine failure. The alternative is a oil catch can.