Mark Gearhart
December 20, 2016

PCV valves have been mainstream on vehicles since the 19th century, and they do perform a critical task. While we all hope our rings have a perfect seal, the reality is they don’t. Depending on the condition of your engine, some (or a lot) of the combustion gases pass around the rings and into the crankcase. Blow-by, as it’s called, can build up positive crank case pressures if not properly vented.

On the intake side, the incoming air actually helps pull this pent-up gas into your fresh air stream and is routed in a closed loop for emissions reasons. The biggest issue with this system is that the crank case (and the actual crank itself) are whipping up a concoction of air and oil, which is fed into your engine. For boosted engine applications, this issue is compounded and can create even more crankcase smog to enter your intake. This oil can cause a variety of problems ranging from fouled plugs and detonation to the buildup of grime on your pistons and valves.

One of the best bang-for-the-buck mods you can buy to eliminate this issue is an air/oil separator, like one from JLT Performance. Two performance parts that JLT Performance is best known for are air intake systems and air/oil separators. Although many catch cans are available on the market, JLT engineers plug-and-play, application-specific kits.

“Our new 3.0 kit now can hold 3.0 ounces of oil,” says Jay Tucker of JLT Performance. “We were able to make it slightly wider and, with a redesign of the top, double the capacity. What sets us apart is nearly all our kits come fully assembled, which makes for a much easier install.”

JLT makes catch cans for both sides of the engine in many applications, but Tucker stresses that the PCV side is the one to be concerned about. “Ninety-nine percent of the oil will come from the PCV side of every engine; the opposite side is where the engine draws clean air into the engine. Under high rpm and closed throttle, like you would see on a road course, you can experience a quick draw on the clean side and pull oil into the throttle-body. We make the clean side for many vehicles due to the large requests, but we make sure to explain on the website that both are not required.”

1. This is everything you need. A bracket retains the canister to an open hole on the driver-side shock tower via two screws and one bolt.

2. The factory PCV line connector uses a push-to-open connector, while the JLT connectors are slide locks.

3. The filter is a 1/16-inch aluminum honeycomb block along with a fine stainless screen. It’s all about surface area. The more surface area, the heavier the oil vapors can grow and drop into the can.

4. While you don’t absolutely have to remove the engine cover to get to the PCV hose on the throttle-body, it does make the access easier. Two 8mm and two 10mm bolts take about 30 seconds to remove.

5. The intake side of the PCV connector isn’t the easiest to get to if you have man-sized hands. For us, pushing the lock with a flathead screwdriver and pulling the bottom of the connector was the way to get it off.

6. An open bolt hole on the driver-side shock tower looks like it was installed specifically for the JLT air/oil separator.

7. Note the angle of the bracket here. Snug the bolt, but don’t tighten it all the way for now so you will have wiggle room when it comes to lining everything up perfectly.

8. The laser-cut logo on the bracket will line up with the JLT logo on the can, although it can be installed backwards. Use the two Phillips screws to attach the can to the bracket.

9. You will need to jack up the car to get to the PCV line on the crankcase. Another one that’s not fun to get to. The push lock is on the top of the PCV.

10. While still under the car, install the new line from the catch can. Push the fitting onto the PCV and slide the lock closed. Note: The fitting can be clocked accordingly for a better fit.

11. Route the line that goes to the intake manifold under the front of it, and plug it in from underneath.

12. Reinstall the engine cover. Everything fits back in there perfectly, and we don’t have to worry about oil contaminating our engine. Be sure to empty any oil vapors from the can every time you perform an oil change. Best of all, the whole installation should take you less than an hour.