Hello, first post, I have a 99 ranger with the 4.0 OHV engine, just put a new motor in it in March and it's dumping oil into the intake, soaking the oil filter and dripping out of the air box and making a mess. I can't figure out where it's coming from, I put a new pcv valve and it has a new IAC valve. Running royal purple full synthetic oil. Kinda at a loss and idk what to do with it. Any ideas?

 

Welcome to the forum

I assume you are not using a turbo or super charger you forgot to mention?
lol

All piston engines have Blow-by
When a cylinder fires some of those explosive gases "blow by" the piston and rings and into the crank case, and these gases are HOT, hot enough to vaporize oil on the cylinder walls and piston sides, and its the ONLY place oil vapor in an engine can come from, bearings and valve train don't get any where near hot enough to vaporize oil
So ALL the oil vapor comes from Blow-by

The PCV(positive crankcase ventilation) system was added years ago to prevent blow-by from just being sent out into the air, like it was for 60+ years, lol
The PCV Valve creates a slight negative pressure in the crankcase/valve cover areas when engine is running, by using engine vacuum
There is also a Breather Hose on opposite valve cover from PCV Valve to allow fresh filtered air to be pulled in to the engine as needed

Drawing here: https://www.aa1car.com/library/pcv.gif

If you have Oil vapors coming out the Breather hose then you either have WAY TOO MUCH Blow-by, or PCV Valve is NOT working

With engine at idle pull out dipstick, there should be no air flow out of dipstick hole, in fact there should be a slight suction at the dipstick tube

Put dipstick back

Engine running pull out PCV Valve, should be slight suction at bottom of valve, REV engine and suction should go HIGH and then back to low as idle returns

With engine running pull off Breather hose, there should be no air flow out of the Breather, if so then PCV Valve is not working