F150 Oil Separators Explained

In a word, yes. More specifically, it is late model F150s that see the most benefit from installing an oil separator. F150 pickup trucks 2011 and newer, either with the 5.0L Coyote, 2.7L EcoBoost, or 3.5L EcoBoost, are more susceptible to oil build up in the intake due to their PCV system design and thereby stand to gain the most from installing an aftermarket oil separator/catch can system.

Since 2011, Ford has introduced a slew of freshly designed engines. The 2.7L V6 EcoBoost, 3.5L V6 EcoBoost, and 5.0L V8 Coyote have all been introduced to the F150 lineup since then, with fantastic results. One area found to possibly cause problems, across all three engines, is the PCV system.

The PCV (positive crankcase ventilation) system is intended to help reduce engine blow-by and emissions by venting air from the crankcase back into the intake. As your engine operates, air pressure builds inside the crankcase. If there was no way to regulate this air, the pressure in the crankcase would continually increase until the weakest link gives and lets the pressure out (usually a seal). The PCV eliminates excessive crankcase pressure by providing a vent and carrying this contaminated crankcase air back to the intake system to be re-burned.

The issue is the PCV air is always mildly contaminated with oil (why it needs to be re-burned, for emissions, and not just directly vented to the atmosphere) and over time, can build up in the intake manifold and on the cylinder head valves, resulting in sludge or carbon buildup. This issue is further compounded by some Coyote (early models did not) and all EcoBoost engines having direct fuel injection. The air-fuel mix no longer passes over the intake valve as it enters the combustion chamber, which previously acted as a cleaning agent preventing buildup on the valve. As the miles build up on your F150, what started off as a few oil molecules building up in the intake and on the cylinder valves can turn into a layer that may disrupt engine performance and set of a CEL (check engine light). This is actually a predominant reason why new F150 engines are equipped with both port and direct injection fuel systems installed, to combat this problem of oil buildup.

OK, so that is the gist of the problem. An oil separator helps by filtering the oil (“catching it”) out of the air before it is routed back to the intake system. A basic PCV system runs a hose from the crankcase or valve cover directly to the intake tract, dumping the crankcase air prior to the throttle body. A check valve is incorporated to prevent the air from flowing back into the crankcase. Some valves may incorporate a screen to help trap oil molecules, but they aren’t largely effective and can become clogged themselves, also leading to a check engine light and possible idle surging (a common problem back with the Foxbody Mustang, for example).

Specific to 2011 F150s, there is a PCV valve and hose running out of each valve cover. Interestingly enough, it has been observed the passenger side PCV systems seems to shoulder the load of venting the crankcase, and thus most aftermarket oil separator kits only provide provisions for the passenger side. Oil separator kits that incorporate both passenger and drive sides are available; however, they are largely more expensive. Anyway, a passenger side oil separator will come with new hoses and a new canister that needs to be mounted in the engine bay. Depending on the size of the catch can, they can mount either on the passenger side firewall or behind the front grille. A hose with a factory fitting will connect to the passenger side valve cover, but instead of heading directly to the intake tube, instead is diverted to the inlet on the catch can. Often made from CNC aluminum, these catch cans feature a multi-layer mesh screen to filter and trap the oil molecules as the air passes over. As the can fills, depending on construction, there is either a drain valve at the bottom, or in the case of a two-piece catch can, the bottom portion will unscrew and can then be emptied. A separate exit flows the now oil-free air back into the intake tract. A dual passenger/drive side oil separator will have one other inlet to accommodate the drive side hose.

For those of you whom are still uncertain about this whole oil separator deal, consider this. Ford Performance has developed their own oil separator system that works with 5.0L Mustangs and F150s, and they claim it to be one of their most popular pieces.