What is the main purpose of a catch can?

 

Rking: Wait till you run it for 1,500 or so miles and then check the can,,, Mine was about 5/8" deep.

I drive like Grandma and I'm currently using Mobil 1 oil,,, Based on the first few times I've checked mine, I fully anticipate the can to be '1/2 to 3/4 full' in 5,000 miles,,,

Not a lot of 'ounces' in the overall scheme of things, and not enough loss to notice on the dipstick, but why burn it up if ya don't have to? =)

 

Not a lot at once but think of the life of the truck how much you'll not burn at 100K. I also use mobile 1. Thanks for you help Scott. I figured that was the hose but wanted to make 100% sure first cause the can came with no instructions at all.

The hemi is designed to feed very small amount of oil back into the engine which is then burned off. However in the long term this dirties you TB and can affect mileage not to mention possibly the engine itself. A catch can intercepts this oil and collects it into the "can" which you empty at every oil change. Sometimes you can get small traces of oil on your air filter also. I bought a K&N drop in filter and would like to save it as much as possible as well-another reason I got it. I ordered one as soon as I read about it.