Pcv hose crankcase - 2004 Mazda MPV

Crankcase ventilation system is used to consume crankcase vapors created during the combustion process instead of venting them to the atmosphere.
Fresh air is supplied through a filter to the crankcase, the crankcase mixes the fresh air with the blow-by gases and then passed through a positive crankcase ventilation (PCV) orificed tube into the intake manifold.
The PCV orificed tube restricts the flow rate of the blow-by gases using a 3 mm (0.118 in) (a) orifice located at the end of the tube. If abnormal operating conditions arise, the system is designed to allow excessive amounts of blow-by gases to back flow through the crankcase vent tube into the throttle body in order to be consumed by normal combustion. Positive Crankcase Ventilation Hose/Pipe/Tube Replacement
Remove the two nuts (2) from the fuel injector sight shield (1).
Lift the sight shield (1) from the front and pull forward to disengage the rear tab from the bracket.
Disconnect the PCV fresh air tube from the left camshaft cover.
Remove the PCV fresh air tube from the throttle body.
Remove the drive belt. Refer to Drive Belt Replacement .
Remove the power steering pump retaining bolt.
With the hoses still attached, Carefully position aside the power steering pump.
Remove the retaining clip securing the PCV dirty air tube.
Disconnect the PCV dirty air tube from the PCV orificed tube.
Remove the PCV dirty air tube from the intake manifold.

function for a pcv valve or positive crankcase ventilation valve what the pcv valve does it is a check valve with hoses directing crankcase blowby gases back into the combustion chambers in the engine.

Here's a link to the pcv valve,could be glogged up causing pressure to back up,Here's the pcv valve.

in general the PCV (positive crankcase ventilation) valve is located in one of the valve covers it will have a hose attached that runs the air cleaner or throttle body. simply remove this hose, remove PCV from valve cover, install new PCV re-attach hose and your done

About the only thing that would need cleaning would be the PCV valve itself. It is in the valve cover with a hose attached to it. If you take it out of the valve cover and shake it, does it "rattle"? if so then it is okay, if not then just spray some carb cleaner in it after taking it out of the valve cover and disconnecting the hose.

All the PCV system does is vent Crankcase gases back into the engine. Internal combustion engines will lose "compression" through the piston rings and it will bild up in the crankcase. the PCV routes those gases back into the intake of the engine. the PCV valve will open and allow gases to vent from the crankcase, but will close so that nothing gets back into the crankcase.

The blowby vapors that end up in an engine's crankcase contain moisture as well as combustion byproducts and unburned fuel vapors. The crankcase is sealed to prevent the escape of these gases into the atmosphere, but the vapors must be removed to prevent oil contamination that leads to sludge formation. The positive crankcase ventilation (PCV) system siphons these vapors from the crankcase and routes them into the intake manifold so they can be reburned in the engine.

The main component in the PCV system is the PCV valve, which is usually located in the valve cover. A hose connects the PCV valve to the intake manifold. A second hose between the air cleaner and crankcase or other valve cover (V6 or V8 applications) provides fresh air to help flush the vapors out of the crankcase. Some engines have a separate air filter for the PCV breather hose located inside the air cleaner.
Probably not read above for details.

Usually you grasp it an pull it out.

Positive Crankcase Ventilation (PCV) Valve Removal & Installation To Remove:
PCV Valve location (3.3L & 3.8L engines shown, 2.4L similar)

1. Disconnect the vacuum hose from the positive crankcase ventilation (PVC) valve.
2. Remove the positive crankcase ventilation valve from the valve cover.

To Install:

1. Install the positive crankcase ventilation valve in the valve cover.
2. Connect the vacuum hose to the positive crankcase ventilation valve.

There are just a few things that cause this condition, The first to check is the engine oil level, overfilled crankcases cause this oil to be forced into the air cleaner through the crankcase air vent hose, the next reason PCV (positive crankcase ventilation) crankcase ventilation system is defective or plugged, check the PCV valve and the large vacuum hose to it, make sure the valve sucks tight on your finger when you put your finger on the end (valve pulled from engine of course) with the engine running, watch the vacuum hose to make sure it doesn't collapse and you are losing vacuum, ok all that checks ok? then the only thing left is excessive engine crankcase pressure, this is caused by worn piston rings or a scoured cylinder wall or a damaged piston skirt.

Not sure what vehicle you have, but it sounds like the PCV hose. Is there a small metal valve at the hose where in enters the valve cover grommet?

I think it is in the valve cover. see illustrations from shop manual.



Positive Crankcase Ventilation System Overview The Positive Crankcase Ventilation (PCV) System (Figure 132)cycles crankcase gases back through the engine where they are burned. The PCV valve regulates the amount of ventilating air and blow-by gas to the intake manifold and prevents backfire from traveling into the crankcase. The PCV valve should be mounted in a vertical position. On some applications, the PCV system is connected to the evaporative emission system (refer to the VECI decal). located on the underside of the hood or on the radiator cooling fan shroud.

crankcase ventilation tube

1. Remove the positive crankcase vent (PCV) hose from the clips.