PCV Breathers

K&N Vent Air Filter/Breather (62-1030) K&N Vent Air Filter/Breather (62-1030) Quick View
K&N

K&N Vent Air Filter/Breather (62-1030)

$34.99
BBWQ_62-1030
Emission Control K&N PCV Breathers
K&N crankcase vent filters are perfect for racing applications, vintage cars or individuals who want to add some aesthetics to their classic carbureted engine....
K&N Vent Air Filter/Breather (62-1020) K&N Vent Air Filter/Breather (62-1020) Quick View
K&N

K&N Vent Air Filter/Breather (62-1020)

$34.99
BBWQ_62-1020
Emission Control K&N PCV Breathers
K&N crankcase vent filters are perfect for racing applications, vintage cars or individuals who want to add some aesthetics to their classic carbureted engine....
K&N Vent Air Filter/Breather (62-1015) K&N Vent Air Filter/Breather (62-1015) Quick View
K&N

K&N Vent Air Filter/Breather (62-1015)

$34.99
BBWQ_62-1015
Emission Control K&N PCV Breathers
K&N crankcase vent filters are perfect for racing applications, vintage cars or individuals who want to add some aesthetics to their classic carbureted engine....
K&N Vent Air Filter/Breather (62-1010) K&N Vent Air Filter/Breather (62-1010) Quick View
K&N

K&N Vent Air Filter/Breather (62-1010)

$34.99
BBWQ_62-1010
Emission Control K&N PCV Breathers
K&N crankcase vent filters are perfect for racing applications, vintage cars or individuals who want to add some aesthetics to their classic carbureted engine....
K&N Vent Air Filter/Breather (62-1000) K&N Vent Air Filter/Breather (62-1000) Quick View
K&N

K&N Vent Air Filter/Breather (62-1000)

$24.99
BBWQ_62-1000
Emission Control K&N PCV Breathers
K&N crankcase vent filters are perfect for racing applications, vintage cars or individuals who want to add some aesthetics to their classic carbureted engine....
K&N Crankcase Vent Filter (62-1330) K&N Crankcase Vent Filter (62-1330) Quick View
K&N

K&N Crankcase Vent Filter (62-1330)

$34.99
BBWQ_62-1330
Emission Control K&N PCV Breathers
K&N Performance Fuel Filters are built for high flow rates and capacity while they provide outstanding filtration. They have a high strength carbon steel...
Air/Oil Separator Black For Subaru 02-07 WRX 04-21 STI 04-08 FXT GrimmSpeed Air/Oil Separator Black For Subaru 02-07 WRX 04-21 STI 04-08 FXT GrimmSpeed Quick View

GrimmSpeed Air Oil Separator Black - Subaru Turbo 02-07 WRX/ 04+STI/04-08 FXT (078006)

$299.00
JBCB_078006
Emission Control GrimmSpeed PCV Breathers
An Air/Oil Separator has one job, remove the oil from the engine ventilation system so the oil does not get sent through the intake...
Air/Oil Separator Red Subaru 02-07 WRX 04-21 STI 04-08 FXT Grimmspeed Air/Oil Separator Red Subaru 02-07 WRX 04-21 STI 04-08 FXT Grimmspeed Quick View

GrimmSpeed Air Oil Separator Red - Subaru Turbo 02-07 WRX/ 04+STI/04-08 FXT (078006R)

$299.00
JBCB_078006R
Emission Control GrimmSpeed PCV Breathers
An Air/Oil Separator has one job, remove the oil from the engine ventilation system so the oil does not get sent through the intake...
Air/Oil Separator Black For Subaru 08-14 WRX 05-09 LGT/OBXT 09-13 FXT GrimmSpeed Air/Oil Separator Black For Subaru 08-14 WRX 05-09 LGT/OBXT 09-13 FXT GrimmSpeed Quick View

GrimmSpeed Air Oil Separator Black - Subaru 08-14 WRX/ 05-09 LGT/09-13 FXT (078016)

$299.00
JBCB_078016
Emission Control GrimmSpeed PCV Breathers
An Air/Oil Separator has one job, remove the oil from the engine ventilation system so the oil does not get sent through the intake...
Air/Oil Separator Red Subaru 08-14 WRX 05-09 LGT/OBXT 09-13 FXT Grimmspeed Air/Oil Separator Red Subaru 08-14 WRX 05-09 LGT/OBXT 09-13 FXT Grimmspeed Quick View

GrimmSpeed Air Oil Separator Red - Subaru 08-14 WRX/ 05-09 LGT/09-13 FXT (078016R)

$299.00
JBCB_078016R
Emission Control GrimmSpeed PCV Breathers
An Air/Oil Separator has one job, remove the oil from the engine ventilation system so the oil does not get sent through the intake...
Air/Oil Separator O-ring Rebuild Kit For Subaru GrimmSpeed Quick View

GrimmSpeed Air Oil Separator rebuild kit - Subaru (078029)

$12.00
JBCB_078029
Emission Control GrimmSpeed PCV Breathers
Hardcore heat cycles or repetetive removal can over time wear on the O-rings in the AOS. Maybe you like the peace of mind or...
-4%
Skunk2 Racing Ultra Manifold Breather Filter (943-99-0304) Skunk2 Racing Ultra Manifold Breather Filter (943-99-0304) Quick View

Skunk2 Racing Ultra Manifold Breather Filter (943-99-0304)

$16.79
$15.99
BJWR_943-99-0304
Emission Control PCV Breathers Skunk2 Racing
3/4in. ID Filter for use with Ultra Series Manifolds. Skunk2 Racing Crankcase Breather Filter. Universal 3/4" female connection can be used to filter the...
-5%
57-2100-BLUE.jpg 57-2100-BLUE_closeup.jpg Quick View

HPS 3-ply reinforced oil-resistant silicone direct replacement breather hoses (57-2100-BLUE)

$120.00
$114.00
HTZW_57-2100-BLUE
Emission Control HPS Performance PCV Breathers
This HPS High Temp 3-Ply Reinforced Silicone Breather Hose Kit replaces the R33 Nissan Skyline GTR's old stock OEM breather hoses with premium quality...
Items 37 to 49 of 49 total

 


The PCV (Positive Crankcase Ventilation) system channels harmful crankcase vapors to the air intake in a controlled manner so they can be burned along with the air/fuel mixture. These gases must be allowed to escape from the crankcase or pressure could build up causing gaskets and seals to fail resulting in leaks, and to prevent oil contamination which could reduce the oil's effectiveness and usable lifespan.

All engines, no matter how new or well-maintained, have a certain amount of ""blow-by"", where some of the gases from the combustion chambers leak past the piston rings and cylinder walls. This causes pressure to build up inside the crankcase, which if not provided a path for exit, would instead escape past seals and gaskets, causing engine oil leaks. These gases also mix with moisture in the crankcase to form compounds that are destructive to the engine lubricating oil, causing sludge to form. In the past these gases were allowed to escape from the engine block through a ""road draft tube"", but since they contain hydrocarbons (HC), when it was realized in the 1950s that HC was a major cause of smog, a new method for ventilation was needed.

PCV was the earliest emission control system, first appearing on cars in 1961. In this system air enters the crankcase through a crankcase breather tube. The air is filtered either by the engine air filter or by a dedicated crankcase breather filter element. The incoming fresh air mixes with the crankcase vapors and is drawn out from the crankcase into the intake manifold, where it mixes with the incoming air/fuel mixture and is burned in the combustion chambers. The PCV valve is used to regulate the flow of vapors. It contains a restrictor and a light spring.

At idle, not much blow-by is produced but intake manifold vacuum is high. The high level of vacuum causes the restrictor to be drawn against the spring, limiting the flow of vapors. At low engine loads such as would be experienced at cruising speed, less manifold vacuum positions the restrictor to allow a moderate flow of vapors. During high engine load conditions like acceleration, there is a higher amount of blow-by but also minimal engine vacuum. Under these conditions the PCV valve allows the maximum flow of vapors to the intake manifold.

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