Crankcases and PCV Valves

Basically, a crankcase is the casing for the crankshaft of an internal combustion engine. Combustion produces pressure within the crankcase. Positive crankcase ventilation (PCV) valves regulate the vapor pressure within the engine and recycle it back into the engine.

2,195 Questions
Ford Windstar
Crankcases and PCV Valves
Ford Windstar GL
Ford Windstar LX

Where is the PCV valve and how to install on a Windstar?

PCV Valve locations:

  • 1995-1998 3.0l - front valve cover

  • 1996-1998 3.8l - rear valve cover

  • 1999-2003 3.8l - front valve cover

INSTALL: Simply pull on the hose to release the valve from the valve cover - pull the valve out of the hose. Insert new valve and push back into valve cover.


  • The valve is in the end of 1/2" or so size hose inserted into a rubber grommet in the top of the valve cover

  • If the valve checkball rattles, it's working

  • Recommended replace interval - 40,000 miles

  • The 'other' large tube going into the opposite valve cover is a breather tube

it should be on the valve pan cover with a hose running to air filter duct or MAF(mass air flow) the PCV recycles the blowback exhaust back into the engine .


The PVC valve is on the rear valve cover closer to the driver side of the car. It's easier to see and get to if you pull off the air cleaner housing which is a hassle but once you get it out of the way, you can get to the PVC valve easier. The problem is getting enough leverage to pull it loose from the connector which has a rigid pipe leading to it. It's a snug fit and you have to be able to get a good grip to pull the old one out of the hose. It's fairly easy to pull it loose from the valve cover.

EGR Systems
Crankcases and PCV Valves
Toyota SR5

What is a PCV valve?

PCV stands for positive crankcase ventilation.

They are usually right in plain sight on top of the valve cover. If you had one you probably could have changed it yourself in about 30 seconds or less.

A PCV valve helps keep a constant pressure within the engine block by releasing oil fumes when they get to a certain pressure and sending them into the fuel system to be reburned with the gas.

While they can be inexpensive, they can be very hard to locate and remove on several makes of cars and trucks. Some are internal and cannot be replaced, meaning they are located inside the valve cover.

The PCVs that can be replaced should be replaced every 15 to 60 thousand miles depending on the make and engine you have.

Shop around for a better price than you paid, $12.00 is a little steep.

It stands for positive crankcase ventilation. And what they told u was right about replacing it. All it does is prevent condensation build up and burn fuel fimes that get by the rings. The condensation will build up and create sludge and that is a bad thing because it will block oil galleries and return holes and ur engine will run oil dry and it will be fried.

pos.crankcase vent keeps pressures even in your eng.returns fumes to the intake threw the air filter houseing.easy to check shake it if it rattles it should be good put it back

The answers are correct as to what it does, and how it is to be checked, though usually the "prescribed" way to check it is not just shaking, but trying to suck, or blow, air in both directions (it should be one-way).

However I have never heard of routinely replacing this item, and have known some cheapskates actually "revitalizing" them by spraying them with engine cleaner.

As to price, $9 is too cheap for a professional oil (and filter?) change, so they nailed you for the valve, by its cost, and probably by its need.

There isn't any free lunch.

buy one and keep it in your glove box. change it every other year. it is an emmission control device. it takes blow by and directs back to be used again. it is cheap insurance and prevents sludge. change it every time you get a tune up also change your airfilter out at the same time. If your airfilter is oil soaked, it probably due to a worn pcv valve. change the valve first then change the airfilter.

The PCV Valve, or Positive Crankcase Ventilation valve is an emission control device that routes unburned crankcase blowby gases back into the intake manifold where they can be reburned. The PCV system is one of the oldest emission control devices, and also one of the most beneficial. Besides totally eliminating crankcase emissions as a source of air pollution, the constant recirculation of air through the crankcase helps remove moisture which otherwise would cause sludge to form. Thus the PCV valve extends the life of the oil and engine. The PCV valve requires little maintenance. The valve and filter should be replaced somewhere around 30,000 to 50,000 miles(see the vehicle owners manual for service intervals).

PCV is an acronym for Positive Crankcase Ventilation. This valve is needed to relieve the pressure built up in the crankcase that is created by the heating of the air inside the engine. If this valve were not present and the pressure went unchecked, it would blow out the seals and gaskets inside your engine.

PCV stands for Positive Crankcase Ventilation. This replaceable valve replaced the vent pipe on the engine, this got rid of the fumes and or pressure that builds up in the crankcase, nowadays the crankcase does not vent into the environment. with the PCV valve these fumes are returned to the intake manifold and are mixed in with the fuel intake stroke to be burned and so create a cleaner exhaust.

Pcv valveI don't think a car has been built in the last 40 years that doesn't have a PCV valve. My 1965 Galaxie had one, but my 64 Ford pickup didn't. PCV means "Positive Crankcase Ventilation", in other words actively sucking junk out of the crankcase rather than just letting it be vented to the air.

The PCV valve allows unburned stuff that blows by the piston to be collected and re-burned rather than just vented to the air, without causing your engine to stall out at idle. This results in a serious reduction in air pollution at virtually no cost, which is why it was the first emissions control device employed.

Look on top of the valve cover. There should be a knob sticking out with a small diameter rubber hose attached to it. It will be inserted in a rubber grommet. You can just pull it out of the valve cover. If it's clogged it will be unnecessarily blowing junk into the air; if it's leaking, it will seriously foul up operation of your engine, especially at idle. They cost about two bucks and you can change it with your bare hands. Replace often. The book says 24000 miles/24 months. I always write the replacement date on them with a Sharpie so I can remember when I replaced it last.

Oil and Oil Filters
Head Gaskets and Valve Covers
Crankcases and PCV Valves

Why oil pressure drop as an engine reaches operating temperature?

As the oil heats up it goes it flows much easier. This requires less pressure to move the oil throughout the engine. ALSO as described above, the viscosity (thickness) of the oil ,decreases which in turn makes oil flow, even in the narrowest area's, more freely. like electricity, more resistance, less current/flow, voltage (pressure) increases. but the reverse is also true..LESS resistance(thinner oil viscosity) when oil is hot. resistance to oil flow decreases, and the pressure (voltage) decreases.

Crankcases and PCV Valves
Chevy Blazer S-10
Ford Bronco XLT

How often should the PCV valve be replaced?

* It should be specified in the owners manual, and if not, they are relatively cheap ($3-$8) so you could do it when you do a tune up. Check it by popping it off with the engine off (it is located on the top of the engine usually and connected by a small hose) and shake it. It should rattle. If not, it is clogged and needs to be replaced. Here are more opinions and answers from FAQ Farmers: * PCV valves are probably the easiest and cheapest part of keeping the engining running smoothly. They should be changed annually or at least every 2 years. * How often? NEVER. Trade secret among mechanics is take it off every 10-15k miles and soak it in gasoline or other solvent to remove all the gummy oil deposits left by venting the crankcase.All it is is a check valve that is activated by the amount of vacuum a motor creates. I've never bought a new PCV valve for any of the cars I've owned since I started driving 35 year ago. Back then of course,you could work on your car unlike today.Lift the hood and you can't even see the road where as before,you could climb inside under the hood and still have enough room to work.Now you HAVE to bring your car back to the dealer to have it worked on because of all the sensors,valves,computer modules etc's a scam! Save your money on a new PCV valve and just use a little gas from your lawn mower to clean the one you have. * The pcv should be replaced every 35,000 miles. Just cleaning the pcv is not enough. The part that fails on the pcv is the spring and cleaning it will do nothing. This part is cheap and can have a significant impact of gas mileage and on how smooth the car runs. Not the place to be cheap.

Crankcases and PCV Valves
Honda Civic DX
Honda Civic EX

Where is the pcv valve on 1998 Civic DX?

I have never worked on a 1998 Civic but I have worked on a lot of Hondas. I have worked on 88,90,91,92,93 and a 95 Civics. the pcv are right under intakes.

Crankcases and PCV Valves
Chevy 350

Why is the exhaust valve seat is made wider than the inlet valve seat?

Better heat distribution. The exhaust valve sees a lot more heat.

Crankcases and PCV Valves
Toyota Camry

Do you need to replace the existing shower valve if you want to change the exterior fixtures?

Not always, there is a standard shower valve that most handles will work for. it depends on what your set up is. As far as the shower head is concerned you should be able to put anything on.

As I'm standing at Home Depot looking at all the different shower valves on the display I wonder which one is the "standard" that all handles and trim fit on. The fact is unless you are replacing with it the same valve or in some cases the same brand all the trim plates and handles have to be changed.

*It TOTALLY depends on the brand and make of your faucet. You would have to determine what brand the faucet is(ex. Moen, Delta), The next move is to determine which model it is(ex. Moen Heritage, Delta Leland). Then you get their own catalogue # and determine what cover plate, handle and screws will fit onto your existing faucet, order them, and replace them. ALL FAUCETS AND THEIR PARTS ARE MADE DIFFERENTLY!!!*Cheers, QuiteSomething

Ans 4 - YES, you DO need to replace this valve unless your new fixture is identical

Crankcases and PCV Valves

What would a bad PCV valve cause to the engine?

Typical symptoms are oil leaks due to abnormally high internal pressures forcing oil past gaskets and seals.

Honda Civic EX
Cars & Vehicles
Crankcases and PCV Valves

Where is the PCV valve on 1998 civic ex?

Should be located just above the oil filter.

EGR Systems
Crankcases and PCV Valves
Mercury Sable
Toyota SR5

Where is the PCV valve on a 1996-1999 Sable 3.0 Duratec 24v DOHC?

The PCV valve is on the right side of the engine compartment, if you're facing the front of the vehicle, just under the air intake hose. Its not directly on the engine but rather inline with the oil separator tube/hose.

A) To access this area and change the PCV valve just follow these directions. They aren't as complicated as they seem... # using a 5/16" socket, loosen and remove the positive side cable of the battery.

# using a 5/16" socket or nut driver, loosen the worm drive clamp that holds the breather hose onto the manifold.

# next unsnap the clamps that hold the breather hose to the air filter housing.

# noting their positions disconnect the 3 airlines that connect to the breather hose.

# disconnect the 2 electrical connections from the air intake hose. The front one is the mass air flow (MAF) sensor and the back one is the intake air temperature (IAT) sensor, remove the air intake hose and set aside.

# now using a 5/16" socket remove the 2 screws holding the throttle cable cover.

# remove the 2 screws holding the throttle cable bracket. You now have the best access to the PCV valve. B) Now to replace the PCV valve pull the u shaped hose off the elbow. I recommend purchasing this molded new hose for about dollars from your Ford dealer. They tend to clog or collapse after several years. Next simply pull the PCV valve out of the oil separator hose and insert the new one. The whole process can be done in 15 to 30 minutes and save you a lot. C) Now just reinstall everything in reverse. The PCV valve is located on the drivers side, underneath the silver intake manifold. Follow the black accordion tube from the air cleaner to the throttle body valve. Place your hand on the bottom of the throttle body and you will find the PCV attached to two short rubber hoses. Hand access is limited, so you have to feel for the PCV and blindly remove the hoses from the PCV. Be patient, and allow time to finesse the new PCV onto both hoses. While you're at it, be sure to check the condition of the connecting hoses. I found one of mine to have totally collapsed on my 1998 DOHC v6. there is a pcv valve. it is located under the "snorkel" of the upper intake manifold. it is accessed by removing the vacuum line from the front valve cover at the rubber connector between the air filter housing and throttle body(swing out of the way, to the left is best). next remove the two screws that hold the throttle linkage cover in place and remove the cover. third remove the throttle return spring. you can now reach the pcv valve for removal and replacement. It's at the right rear corner (facing the engine), tightly underneath the throttle body. It is in-line in 1/2 inch or so diameter hoses - look for where the one of these hoses takes a 90 degree turn. 97 Merc sable, 12, valve, 3.0 liter, vulcan engine: located on top of intake manifold box, vertical position facing down. manafold box is on passsenger side, near firewall. horizontal hose extends to the right.

Crankcases and PCV Valves
Ford Crown Victoria
Honda Civic EX

What is the second connection on a 97 Crown Victoria PCV valve for?


American Cars
Crankcases and PCV Valves
Chevy Suburban
Toyota SR5

Where is the PCV valve on a 1992 mercury topaz?

It is positioned in the valve cover.

Crankcases and PCV Valves
Dodge Avenger
Toyota SR5

Where is the PCV valve on a 1996 Dodge Avenger?

Along the top of the valve cover - along the back side. It has a black tube between it and the intake manifold. It is a little black plastic piece in the shape of an "L".

Crankcases and PCV Valves
Ford Ranger
Check Engine Light
VW Jetta

How do you reset the check engine light on a 1997 Mazda 626?

"Disconnect the negative terminal and push brake pedal for 30 seconds" worked great! One note: You must use actual key to unlock doors after battery disconnect to reset car alarm so car will start.

I recomend getting the car checked out by a professional. And you never unhook the positive battery cable first, you always do the negative firstl. And sometimes when you do this it erases the computers memory. so take to a professional.

If you HAVE TO, disconnect the negative battery terminal. Put your foot on the brake pedal for 30+ seconds.

I tried the previous answer of removing the negative battery cable, and holding the brake pedal for 30 seconds and it WORKED!!! Just got back from the emissions test, and passed. THANKS!!!

I got check engine light problem just happened few hours ago, my car is 1999 Mazda 626 ES, and I tried the previous answer of above- revmoving the negative cable as well. It REALLY WORKS. It saved my time & money ^^

[Apr 27, 2008]Just applied this method "disconnect the negative battery terminal. Put your foot on the brake pedal for 30+ seconds.", it just worked perfectly. Save me lots of worries and trouble to send the car to mechanics. Thanks so much to the one who posted this method.

i just used removed the negative battery and stepped on the brake for 30 seconds on my 2000 626 es and it worked! saved $80

Just did wt u said and it really works...thanks a million

Same thing works on a 2006 MX 5 Miata....light came on due to loose gas cap and I sure did not want to pay the dealer to reset the dang thing.....Advisable to check out why you have the light at AutoZone or most other parts houses before you reset the light.

a car scanner can help you.

Fuel and Fuel Intake
Crankcases and PCV Valves
Ford Taurus

Where is the PCV valve on a Taurus with standard - NOT DOHC engine?

The following information applies to the 'regular', 12 valve "Vulcan" engines pcv valve.

For the 24 valve, DOHC engines, see "Related Questions" below ----

PCV Valve is in the end of 1/2" or so size hose inserted into a rubber grommet in the top of one of the valve covers.

INSTALL: Simply pull on the hose to release the valve from the valve cover - pull the valve out of the hose. Insert new valve and push back into valve cover.


* The valve is in the end of 1/2" or so size hose inserted into a rubber grommet in the top of the valve cover

* If the valve checkball rattles, it's working

* Recommended replace interval - 40,000 miles

* Can clean with a bit of carburetor cleaner spray

* The 'other' large tube going into the opposite valve cover is a breather tube On my 2000 3.0L Vulcan OHV, the PCV is located on the top of the engine in one of the valve covers, simply pull the old valve out and push the new one in. Cost of part: $2-$4.

If by "standard" you mean the Vulcan engine, the PCV valve is on the valve cover closest to the firewall, passenger side. on an ohv v-6 engine it's in the rear valve cover. on an ohc v-6 it's in an oil separator in the lower intake manifold.

Crankcases and PCV Valves
Chevy Silverado
Nissan Sentra
1982-1994 Chevy Cavaliers

Where is the pcv valve on a 93 Nissan Sentra and can it leak oil?

Automobile PCV valves can leak oil.

Not sure where it is on that model;it will be attached to a hose assembly to let air from the crankcase (bottom of the engine) get sucked back into the intake (top of the engine).

AnswerThe pcv value is located on the value cover next to the oil cap. The pcv value has a hose attached to it that goes from the pcv value to the bottom of the fuel injector. Once you remove this hose, the value can be easily removed with a 3/4" or 20mm wrench.
Car Computers and Sensors
Crankcases and PCV Valves
Dodge Dakota
Crankshaft Sensors

Where is the crankshaft sensor on a 1991 Dodge Dakota?

Can't find it

Crankcases and PCV Valves
Nissan Maxima
Toyota RAV4
Ford F-150
Grand Am SE

Where is the PCV valve located on a 1991 Ford F150?

I have a 5.8L in my 1990 and it is located behind the intake on the passenger side. Right by the valve cover.

Crankcases and PCV Valves
Pontiac Grand Prix
Grand Prix GT

05 grand prix gt PCV valve location?

The 2005 Grand Prix Base model and GT models have 3.8L's and the GXP models have the 5.3L V8. I know the location on the 3.8L.

- Take the engine cover off

- Look at the very top of the motor, the intake manifold.

- There are fuel rails running over the top of this manifold.

- There is a bolt holding 2 of the rails in place right in the middle.

- To the bottom right of this bolt is the PCV valve.

- It has two bolts holding it in and no lines running to it.

Infiniti I35
Oil and Oil Filters
Crankcases and PCV Valves

Where is the PCV valve location on a 2002 Infiniti you-35?

Crankcases and PCV Valves

Where is pcv valve located on 302 engine?

Usually on the passenger side valve cover. If you look at the vaccum routing sticker it will show it's approximate location.

Crankcases and PCV Valves
Mercury Villager
Nissan Maxima
Grand Am SE

Where is the PCV valve located on a 1995 Mercury Villager LS?

in the valve cover on the passenger side It is on top of metal intake, very close to throtle body. It is like 6" from a vacuum line coming from brake booster to the intake. on the intake, it is between the air idle control valve and the egr valve. u will see or feel the rubber hose sticking out of the rear of intake, the pcv valve is threaded into intake. the rubber hose is attached to it. according to manual, if u take off hose with car running, and there is a vacuum present, then valve is working.

Crankcases and PCV Valves
Honda Civic
Honda Civic LX

Where is the pcv valve located on a 1996 Honda Civic?

the pcv tube is between the intake manifold a little tube going into the engine. On the I4, it is located underneath the intake manifold, but slightly above the oil filter. It's difficult to see, but if you look from the driver's side through an opening under the intake manifold, you'll see a sensor. To the left of it and slightly below you should see the PCV valve. It's a little elbow with a clamp around it and a tube going out and will probably be covered in oil.

Crankcases and PCV Valves
Crankshaft Sensors

Could a broken PVC elbow or vacuum line cause the crank position sensor to go out?

No it wouldn't, but jump starting the car or over heating the engine would crap out the sensor.

I'm in the process of changing my crank position sensor now, but my original broke in my engine block ... so I need to drill a hole so I can pull it out without pushing it in my block. :(

Crankcases and PCV Valves
Honda Civic DX

Location of the PCV valve on a '98 Honda Civic DX?

Mine is Civic DX 97. Believe it's the same. Get under your car, take off your oil filter, your PCV valve is right above your oild filter. It's recommended to replace it from there. Good luck!


Copyright © 2020 Multiply Media, LLC. All Rights Reserved. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply.