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PCV Hoses for EFI engines, EXCEPT MAF
IF THE IMAGE IS TOO SMALL, click it.
The rubber hose connecting the hard plastic PCV vent tube (F5TE6C324AA) to the nipple on the oil filler neck of the valve cover can be replaced with F7UZ-6A664-AA, as can the PCV valve lower hose (E9UB-6A866-AA) which connects to the elbow (6762, Dorman 47046) in the valve cover grommet (6K780/E7AZ6A892A, Standard GV27, Dorman 42049). The straight hose shown at the breather end can be replaced with common 5/8" Fuel/PCV/Emissions hose to connect the hard plastic elbow that fits FA1047, but later trucks use a rubber elbow that can be replaced with Dorman 47028 for the smooth barb on FA1603.

Before madly ripping out all the emissions systems on your vehicle, read this article to learn how each one benefits the engine.

The change from the early V8s' routing to the revised routing is described here:
http://oldfuelinjection.com/files/Reroute_PVC.pdf
If that link doesn't work:
.

The PCV System -

No matter how new or well-made an engine is, the piston rings (or seals in a Wankel rotary) can't capture 100% of the combustion gases. There will always be some blow-by, resulting in contamination of the crankcase oil. These contaminants most often include water (the ideal result of combustion, which remains a vapor at normal engine temperature), fuel (fuel molecules are smaller than oil molecules, so they pass by the rings more easily), soot (which turns the oil black), and various acidic gases. To reduce the accumulation of these contaminants (which rapidly affects the oil's viscosity & effectiveness), the crankcase must be positively ventilated. This means forcing a draft of air through the crankcase to carry these vapors out. But rather than venting them under the hood, the vapors are contained within the PCV system and routed into the intake system to be burned in the engine.

Since the system is powered by negative pressure (engine vacuum), I'm going to describe it in reverse:

The PCV system ends with a tube (6A866) carrying the vapor-laden (& often oil-laden) airstream into the intake manifold to be burned. This tube comes from the PCV valve (5.8L Motorcraft EV68C/E7TZ6A666A, 5.0L Motorcraft EV-140/E7TZ6A666A, 4.9L Motorcraft EV49B/D8TZ6A666A/D8TZ6A666B), which regulates the quantity of air "leaking" into the intake, and also contains a one-way valve to prevent backfires in the intake from burning into or over-pressurizing the crankcase. (The valve or the tube may include another port where the fuel tank vapor system is combined.) The PCV valve is installed either in an oil separator chamber outside the crankcase, or in a valve cover which often contains an oil separator, or sometimes midway in the tube to make access/replacement easier. The valve must be replaced regularly because its mechanism is lightweight (generally gravity-operated), and is easily fouled by normal engine operation. The oil separator is necessary to prevent crankcase oil from entering the intake system, fouling sensors, coating the valve stems (which accelerates wear on the valve guides), fouling the spark plugs, or increasing HC emissions. Because most oil separators are not designed to be easily serviced (and rarely if ever appear on any maintenance list), their benefit is typically lost on high-mileage vehicles, and the inside of the intake manifold suffers. The airflow thru the separator comes from the crankcase, where undesirable vapors have boiled out of the oil. On engines with 2 banks of cylinders (V or flat), the airflow is generally into one valve cover, down thru the oil drainback journals in that head, into the crankcase in the block, up the other drainbacks, & into the 2nd valve cover. On inline engines, the flow is most commonly in one end of the valve cover & out the other, but some have the oil separator on the side of the block near the pan so flow is down from the valve cover to the crankcase. The airstream enters the valve cover either thru a dedicated nipple on the cover ('87-96 4.9L Motorcraft FA1118), or thru a vented oil filler cap. In either case, the airstream originates with a fresh-air "breather" filter, usually inside the engine air cleaner housing ('80-87 all carb engines Motorcraft FA675; '84-96 all EFI engines Motorcraft FA1603), but sometimes simply mounted directly on a valve cover.



Several failures are common in the PCV system; the most-often noticed is oil contamination in the intake &/or the air filter housing. Oil in the intake generally indicates that the oil separator has become restricted, which might be caused by gelling of the oil from moisture buildup due to insufficient PCV flow because the valve hasn't been changed on-schedule. But infrequent oil changes or overheating, or any combination of these conditions can contribute to oil in the intake. Oil in the air filter housing is almost exclusively caused by reverse-flow in the fresh-air tube, which is often the result of worn/stuck rings, hardened exhaust valve stem seals, or a ruptured head gasket. But it may also result from low-quality oil, incorrect viscosity oil, or excessive oil. An often-overlooked failure in the PCV system is cracking of the hoses, resulting in vacuum leaks & contamination of the engine oil. All vulcanized rubber (tires, hoses, bushings, etc.) ages & deteriorates, so it must be replaced as needed. A symptom that shocks many people is the presence of light-colored foamy oil residue inside the filler cap, or in the valve covers. And while it's possible that this effect can be produced by severe engine damage (like coolant in the crankcase), it's much more likely that it's caused simply by the vehicle being used only for short trips, during which time the engine never fully heats up to boil the water out of the oil. The moisture naturally condenses in the coolest parts of the crankcase, which is the thin upper sheet metal valve covers & filler neck. It may also be noted in the top of the dipstick, where the water may also cause rust.

MAF 4.9L inlet hose:


Before buying cheap aftermarket parts, check for coupons & service offers from Ford.