Project Cherokee - Mishimoto Oil Catch Can/ Air Oil Separator

A product that fits, looks amazing and is purpose built. Most cars don't come with oil catch cans, but they should! Removing the oil from the air back into the intake reduces the coating of coat on the intake manifold, valves and piston tops. This provides more consistent performance over time. While less necessary on an NA engine, it's cheap insurance and easy to install.
Filmed on iPhone 13 Pro. 4k24.
#jeepcherokee #mishimoto #oilcatchcan

[@danhambrick6331]

That's a nice catch can...👍👍

[@rgsrails]

Though this is 3 months after the video posted I'd like to point out to future viewers that the CCV system (not PCV in this period of the 4.0L production) on the '91-01 XJ with 4.0L uses an orifice elbow installed in the rear valve cover grommet instead of the typical sprung ball valve of the typical PCV system. The orifice elbow is connected to manifold vacuum via a 3/16" hard line to prevent collapse and maintain a constant vacuum to the elbow. This is a measured vacuum leak the ECU/PCM is programmed for with input from the MAP sensor.
The other elbow is the unrestricted vent and gets filtered air from the air filter box. The air flow is from the air filter housing above the filter, through the crankcase, out the orifice elbow and into the manifold. The manifold vacuum side of the other elbow is much stronger than at the air filter end and thus no vapors will really be captured from that side. In the configuration shown here, you will have a large vacuum leak inside the crankcase that can potentially suck oil from under the valve cover. It will really cause some messy-ness in the intake, gum up valves, and result in oil fouled spark plugs, contaminated catalytic converter (if still equipped) and lots of smoke. The emissions sticker shows the correct vacuum routing.
To make the 2-port catch can work, used the vacuum diagram and insert the catch can in between the CCV elbow and the intake manifold port. Connect the CCV orifice elbow hose to the IN port on the catch can and connect the OUT port to the vacuum port on the manifold. The vent elbow going to the air box does not change. This will keep the system intact and flowing in the correct direction while doing the job the catch can was designed for most efficiently. Hope this helps.

[@motolayne]

Dang this is a great bite of tech info. What’s the source documentation? How do we tell if we have the right elbow on the right port of the valve cover?

[@genpepper3]

Just a question.. Isn't the can suppose to go between the intake valve cover? I maybe wrong tho

[@motolayne]

The van is routed that way, just placed on that side for ease of positioning

[@mohammedmujalled1554]

I did exact same thing then I noticed the oil pressure is suffering going up as normal and the car moving rough

[@motolayne]

Interesting. I’m definitely interested in converting from funky PCV to straight flow AN adapters.