6.7 Power Stroke CCV Oil Separator Information

Closed Crankcase Ventilation (CCV)

The closed crankcase ventilation oil separator is a device that allows crankcase fumes to be extracted and directed into the path of the intake air charge, ultimately landing in the combustion chamber where they are consumed. As part of the process, heavy oil is separated from the less dense exhaust fumes and lower volatility compounds. The denser oil products settle to the bottom of the separator and are are given a pathway to reenter the crankcase. Exhaust fumes and less dense crankcase byproducts that don't settle within the oil separator are introduced to the intake air charge just before the turbocharger compressor inlet. Check valves in the system ensure that all these liquids and gases primarily travel in the intended directions.

The purpose of a closed crankcase ventilation system is to prevent crankcase fumes - a combination of exhaust gases, fuel byproducts, oil mist, and air - from entering the ambient environment. It is considered an environmentally friendly alternative to an open crankcase ventilation system, by which crankcase fumes exit into the atmosphere, typically through a filtered breather or catch can. In general, a crankcase ventilation system is necessary because the pressure within the crankcase is constantly changing with the motion of the pistons as they translate within each cylinder. If a crankcase was sealed, this pressure would be relieved (rapidly) by blowing through an oil seal or gasket - whatever the weakest link may be. It is for this reason that crankcase ventilation systems require maintenance to prevent clogging and ensure optimal flow.

6.7 Power Stroke Crankcase Vent Oil Separator Location

On all 6.7L Power Stroke engines, the crankcase vent oil separator is mounted atop the driver side valve cover just behind the primary engine mounted fuel filter (between the fuel filter and firewall). A corrugated hose integrated into the front of the component attaches to a mouthpiece connection at the inlet of the turbocharger compressor housing. Crankcase fumes enter the vent/oil separator through the rear of the unit from a valve cover opening. Denser byproducts (primarily motor oil) settle to the bottom of the separator and flow back into the valve cover through a secondary opening. Lighter gases and fumes flow through the corrugated hose and into the intake air path.

Symptoms of a Clogged Crankcase Vent

The CCV oil separator's role is actually quite significant, thus it can cause a variety of symptoms ranging from benign to significant should it develop a clog or serious restriction. When flow through the unit is restricted its ability to separate oil from the crankcase fumes is hindered, allowing excessive engine oil to enter the intake air pathway and increasing pressure within the crankcase. A clogged or restricted CCV oil separator can cause or contribute to the following conditions:

• Oil consumption, as a result of the inability to isolate engine oil particles from the crankcase fumes. These oil particles then enter the intake air pathway and are consumed in the combustion chamber.
• Ash loading of the diesel particulate filter (DPF), resulting from excessive oil entering the intake air pathway and being combusted. Engine oil, unlike diesel fuel, produces a heavy ash when it burns that collects in the DPF and cannot be completely removed during regeneration cycles.
• External oil leaks, resulting from higher crankcase pressures. If there is restricted, minimal, or no flow through the CCV, crankcase pressure cannot be relieved. This puts excessive stress on gaskets and seals, forcing engine oil past them. The leaks can show up in various locations, and it this has even been linked to failed turbocharger oil seals.
• May contribute to higher fuel dilution rates, as fuel that enters the crankcase has an opportunity to be carried over through CCV and return to the intake air pathway. In theory, the fuel molecules are lighter than engine oil molecules and have a good chance of passing through the oil separator instead of being returned to the crankcase. If CCV flow is restricted, it hinders the ability to extract such crankcase fumes.
• Reduced fuel economy is also linked to a clogged CCV; we've routinely tracked 1 to 2 mpg improvements after replacing clogged oil separators.

Ford has likely revised the CCV assembly design so many times due to some of the more significant conditions that clogging/failures can cause. Although rare, these assemblies have been found to develop leaks at the seams; it is difficult to evaluate whether this is the result of normal use, excessive crankcase pressures, heat/vibration, or quality control issues during the manufacturing process.

6.7 Power Stroke CCV Oil Separator Service Bulletins

Ford TSB 19-2142 (original document published by the NHTSA available through link), dated May 9th 2019, addresses excessive oil consumption in certain Ford trucks that undergo extended periods of idling. While the TSB applies to 2016 to 2019 F-650/F-750, 2017 to 2019 Super Duty chassis cab, and 2017 to 2019 dual rear wheel pickup trucks, it provides insight into problems with prior crankcase vent components that may provide guidance in the servicing and replacement of this part in all vehicles equipped with the 6.7L Power Stroke.

The concern revolves around the findings that the listed vehicles may experience excessive oil consumption due to high crankcase pressure resulting from the filter element in serviceable CCV assemblies becoming clogged and thus restricting flow. The only call-to-action outlined by the TSB is to replace the crankcase vent oil separator with an upgraded part (FC3Z-6A785-F) that does not include a serviceable filter element. We believe this part number has since been superseded.

Ford TSB 18-2301 (original document published by the NHTSA available through link), dated October 1st, 2018, addresses reliability concerns over the CCV hose sensor implemented for the 2014 model year and affecting vehicles built prior to 11/11/2015. Trucks built after 11/11/2015 do not employ a CCV with the hose sensor. Affected vehicles may experience one of the following DTCs or combination of DTCs:

• P04DB, crankcase ventilation hose disconnected
• P04E2, crankcase ventilation hose sensor circuit low
• P04E3, crankcase ventilation hose sensor circuit high

The TSB was issued because these codes were being set on affected vehicles although the CCV hose was connected and the system was functioning correctly. The CCV hose sensor, the only purpose of which is to indicate if the hose is disconnected (this was NOT a restriction sensor), was deemed unreliable and retrospectively deleted through this TSB.

In lieu of a sensor on this hose, the collar (Ford part number FC3Z-6A603-A) was updated from a quick connect type to a permanent connection. All replacement CCV oil separators now utilize the permanent type connector, which makes the system "tamper proof" in the eyes of applicable regulating bodies. This TSB requires a PCM reflash in order to remove the CCV hose sensor from the PCM's list of monitors. Owners of affected 2014 to 2016 vehicles should have this TSB performed if it has not already been addressed.

Crankcase Vent Oil Separator Part Variations

There have been numerous iterations of the same base component and thus numerous part numbers with the generic designation 6A785 (the combination of letters and numbers at the center of a Ford part number designate the generic part type). There are essentially three types or versions of the crankcase vent oil separator that have been used on the 6.7L Power Stroke; CCVs with filter elements, sealed assemblies with no filter, and the filter-less style with a removable access cover.

Crankcase vent oil separators with a replaceable filter element (GC4Z-6A785-A, GC4Z-6A785-D) are the most problematic. Simply put, the filter elements (figure 2 below) are the most prone to clogging and thus this is why they were replaced with a filter-less, sealed unit from TSB 19-2142. These seem to be primarily used in medium duty and chassis cab applications, although some model year F-350 dual rear wheel pickup trucks also utilized this variant. The lid of these CCV separators is secured with a series of bolts with 8 mm heads. These units can, and should be replaced with a filter-less assembly.

The sealed crankcase vent oil separators (figure 3 below) do not have a removable access lid and no replaceable filter element. Internally, these CCV separators have a centrally located baffle system that helps heavy oil settle to the bottom while lighter vapors travel upwards and through the CCV hose. Vent tubes that terminate with small diameter holes (Refer to Figure 4 below) may be susceptible to clogging, but not nearly as vulnerable as the filter type units. While oil is intended to collect and drain around the base of the cylindrical baffle, impeding the flow through the centrally located vent tubes could affect flow performance to the outlet hose.

A third type of crankcase vent oil separators have a removable access lid, but no filter element. These are found primarily on 2020 to 2022 models, although they may have appeared prior and after. The lid is held in place by (7) T30 Torx headed bolts. Internally, there is a simple baffle system near the rear of the assembly and nothing at its center. Ford's documentation for the 2020 model year depicts a centrally located baffle similar to that found on the sealed units, but we have yet to open one up that contained this baffle (part number LC3Z-6A785-C). It is likely that the baffle system was removed as the result of a pre-production redesign to improve reliability. By design, these units are not particularly susceptible to clogging internally.

Note that printed copies of the injector calibration codes are printed on some CCV housings. If the CCV assembly is replaced, these codes should be saved for future use. We recommend, at minimum, taking a good image of these codes for future reference. Alternatively, they can be reprinted and adhered to the new assembly. You may even be able to remove and reapply the factory stickers to the new assembly using a heat gun (take a photo before attempting in case the sticker is damaged during removal).

These units, although fairly open and free-flowing, have a small (approximately 1 inch x 1 inch) vent screen/filter that is not replaceable without destroying the unit (figure 6 arrow). If this clogs, the intended flow and operation of the unit may be altered. Note that, as previously noted, units with the hose connection sensor have been removed and superseded per TSB 18-2301. Vehicle owners should have the TSB procedure performed at their local dealer to remove and disable the CCV hose sensor.

Editor's note - update in progress, we are currently waiting to acquire an oil separator for the 2023 and 2024 model year engines. At time of publishing, this part was unavailable.

CCV Oil Separator Part Numbers by Application

Due to various supersessions, there may be some discrepancies (and exceptions) in the part numbers currently available. Even the Official Ford Parts Website has some discrepancies, including showing no viable replacement part for certain applications.

6.7 Power Stroke CCV Service Intervals

Ford Motor Company's recommended CCV service intervals vary by model year and CCV type; there are at least 3 versions that have been employed and dozens of superseded part numbers. The table below outlines the recommended service intervals for 2011 to 2024 model year 6.7L Power Stroke applications, as outlined in the applicable owners manual/diesel supplement.

[1] - No recommendation, requirement, or mention of CCV oil separator service in the applicable owners manual and/or diesel supplement guide.
[2] - Per applicable owners manual, service required for dual rear wheel and chassis cab trucks only; no service required for F-250 and single rear wheel F-350 pickup trucks.

We highly recommend replacing the CCV oil separator at 30,000 to 40,000 mile intervals because they are all susceptible, in one way or another, to buildup and clogging issues. Although no service interval is provided for all 2011 to 2015 and 2020 to 2024 models because the CCV is a sealed or otherwise non-serviceable, filter-less type assembly, replacement should not be overlooked as the resulting problems can compound. Vehicles still operating filter-type CCV assemblies should consider switching to the sealed/filter-less units on the basis that they were the target in TSB 19-2142 due to clogging concerns. Vehicles still equipped with CCV assemblies with hose connection sensors should consider having TSB 18-2301 procedures performed at their local dealership.

100,000 mile service intervals are far too long and leave the health of the system to chance. No service interval assumes a life-of-the-engine assembly, for which these are not. There are a variety of ways the oil separator can fail or experience a fault, including internal clogging/restrictions and greasy buildup in the valve cover opening (see figure 7 below). In any instance, the resulting conditions are not ideal for engine longevity.

Methods for Removing the Crankcase Vent Hose Connection

Replacing the CCV oil separator requires removing the hose at the mouthpiece connection. This is a permanent, tamper-proof type connection with no easy means of unlocking it for removal. Three plastic tabs under constant tension secure the hose connector in place. The tension of these tabs needs to be relieved in order to safely remove the hose without damaging the mouthpiece.

Since the hose is replaced with the CCV assembly you could simply bend or break these tabs off with a small pair of needle-nose pliers while taking care not to damage the mouthpiece. As far as non-destructive methods go, we're found that sliding paperclips beneath the locking tabs works particularly well because the paperclips stay in place. This process is outlined in more detail in the procedures below.

Note that, technically, you can also remove the hose at the assembly itself. This generally requires applying heat with a heat gun to soften the protective tube, then simply pulling it off. Beneath the hose connector, you'll find an o-ring seal. However, we don't recommend reusing the hose because the removal process appears to sacrifice the connection point and/or damage the hose. All modern replacement CCV assemblies include the hose; there is no reason or justification for reusing one.

How to Replace the Crankcase Vent on a 6.7 Power Stroke

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• Disconnect both negative battery cables.

• Remove the fuel lines from the primary (engine mounted) fuel filter.

• Remove the primary fuel filter (see 6.7 Power Stroke fuel filter replacement for specific details).

• Plug or otherwise secure the fuel lines to reduce spillage and protect from contamination.

• Trace the outlet hose from the CCV assembly to find the mouthpiece connector. Note that the mouthpiece location varies slightly between certain model year ranges.

• Carefully peel back the section of heat shrink tubing covering the outlet hose connection at the intake mouthpiece to expose the locking tabs on the hose connector.

• Using a small screwdriver or pick, pry each of the locking tabs on the hose connector upwards and secure them in this position. Take care not to damage the intake mouthpiece; excessive prying with a sharp object may create deep scratches.

• We recommend using paper clips to secure the locking tabs, but there are a variety of makeshift tools lying around - string, toothpicks, feeler gauges, etc. Since the CCV hose is being replaced, you can also bend the tabs upwards with needle-nose pliers until they break or maintain an unlocked position.

• If using non-destructive means, you will need to secure at least (2) of the locking tabs in the upwards position. You can then pry the third with a thin blade screwdriver and pull away from the mouthpiece to remove the hose.

• Removing the hose can be tedious, especially the first time. It should come off fairly smoothly without excessive prying or force.

• The CCV assembly is secured to the valve cover with (4) bolts requiring a 10 mm socket.

• Remove the first CCV mounting bolt behind the fuel filter canister base.

• Remove the second CCV mounting bolt near the CCV assembly oil drain (near the lower front of the unit).

• Finally, remove the pair of bolts at the rear of the CCV (inlet from valve cover). Access is limited near the firewall, but they can be reached with a 1/4 drive ratchet and extension(s). If available, a swivel socket is also useful here.

• Manipulate the CCV assembly off the valve cover and out of the engine compartment.

• Clean the o-ring/gasket mounting surfaces on the valve cover. Note that a thick, greasy substance often accumulates in the forward (drain) opening; this should be thoroughly cleaned before installing the new CCV assembly.

• Prepare the replacement assembly by lubricating the o-ring/gaskets with clean motor oil.

• Lightly lubricate the CCV hose o-ring (inside hose connector) with clean motor oil.

• Maneuver the new assembly into place, ensuring that the inlet and drain tubes seat evenly against the valve cover.

• Reinstall and snug the mounting bolts; do not overtighten.

• Reinstall the CCV hose by pushing the connector onto the mouthpiece. Once seated properly, it will not pull off. It is not necessary to manipulate the locking tabs during installation, just push it into position until it locks.

• Install a new engine mounted fuel filter.

• Recommend replacing the engine oil and lube oil filter at this time.