Oil in Airbox on the right side of the Engine bay
 

Hello all,
About a month ago I started to notice that an excessive amount of oil was ending up in my air filter, I decided it wasn't a huge deal and replaced the air filter. As of late it has gotten worse, the air filter is about half black with oil and now oil is being spayed onto the bottom of the hood above where the serpentine belt runs. In addition to this a knock has developed somewhere in the engine, though I don't know if its related or not.
So what do you guys think it is? and how much will it cost?

What year is your jeep and how many miles on it. The oil in the air filter is just a blow by issue which is very common. You can replace your crank case ventilation tube and it should be fine. The knock is a different issue though...

It's an 88 with 222k miles.

+1 replace the CCV stuff. It's very common that the rear line gets plugged up and oil starts blowing out the front. You can find information for the Renix Vacuum Harness in cruiser54's thread here: https://www.cherokeeforum.com/f51/cr...2/#post2114748

Also, apparently there's a handy mod to be done on Renix valve covers to lessen the amount of oil that gets sucked up in the first place. Check here: https://www.cherokeeforum.com/f51/cr...2/#post2114753 (I've asked him to check the picture as it doesn't seem to be working)

As for the oil on the front, you'd have to get a flashlight and see where it's coming from. May be the timing chain cover, front main seal, oil pan, or even just something related to power steering.

Knocking can be a zillion things, including the most common loose flexplate bolt: https://www.cherokeeforum.com/f51/ho...ocking-125547/