[nysj83]

Recently, I changed the PCV valve for the first time (at 110k miles 2015 ody) as a preventive maintenance.
It's easy and VERY inexpensive (~$25 for genuine Honda parts) procedure to change yourself. Took me about 5~10 minutes.
I don't recommend using other third party brand as they may not have the 'rattle' you need. I bought one from eBay for $10, a 3rd party one; although it fitted just fine, it did NOT have ANY rattle as if it is stuck open/closed! I returned it and got genuine one.

I'm not 100% sure if this made my car a MPG boost, but ever since I changed the PCV valve, my car range for full tank of gas went from 380 miles to 450 miles! And stayed that way for a month. I normally put gas once every 3 days (driving about 100 miles a day), but now I go on to the 4th day.
I did not do any other 'upgrade' when I changed the PCV valve, not even an oil change. Just changed the PCV valve to genuine part.

The dirty one was some what not 'rattle-y' but still little bit of rattle left. But the new one of course has whole bunch of rattling sound when I shook it.

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When you remove the PCV valve, it may SHOOT OUT of the housing.
So turn your ratchet slowly and grab on to the PCV valve as you remove it.
(EDIT: not sure why the forum-bot flagged this picture as 'adult content')

Some of the online (YouTube) video shows the metal bracket inserted BACKWARD!
This is HOW you should insert the metal bracket.

Obviously the old one is dirtier but that's not the important thing.
Important thing is when you shake them, it MUST rattle! (sounds like a spring inside rattling)


So, the verdict?
CHANGE YOUR PCV valve regularly! I'm planning to do it once every 30k or so. So easy, quick and very inexpensive there is no reason not to do it more often than not.
I thought this would be one of those unnoticeable preventive maintenance, but with such a huge MPG boost I got, I thought I'd share with odyclub community and highly recommend everyone to do it if you haven't done it yet.

 

[Ticket]

did you transfer over the aluminum sleeve or did the OEM one come with one?
I used some glue from a glue stick to keep it stuck to the PCV for installation.

 

[jnissen]

220K miles and never touched it. I must be doing something right!

 

[Ticket]

220K miles and never touched it. I must be doing something right!

changed mine around 95k.
They arent as problematic on these engines.
kids veracruz and some of the older ford 302's if the pcv is stuck open,you could end up with a oil consumption issue, and if not addressed could kill the motor.

 

[phattyduck]

220K miles and never touched it. I must be doing something right!

A bad PCV may not cause obvious problems, but it is still something that should be replaced 'regularly' (maybe with the timing belt or so). A correctly working PCV system helps keep the interior of the engine in better shape (though correct venting of crankcase gasses) and can improve mileage (through keeping appropriate vacuum in the crankcase). Modern (say, last 20-30 years) PCV valves are more complicated than a simple 1-way valve - they actually regulate to a minimum and maximum vacuum in the crankcase, which is why they are sensitive to oil residue build-up.

-Charlie

 

[Ticket]

A bad PCV may not cause obvious problems, but it is still something that should be replaced 'regularly' (maybe with the timing belt or so). A correctly working PCV system helps keep the interior of the engine in better shape (though correct venting of crankcase gasses) and can improve mileage (through keeping appropriate vacuum in the crankcase). Modern (say, last 20-30 years) PCV valves are more complicated than a simple 1-way valve - they actually regulate to a minimum and maximum vacuum in the crankcase, which is why they are sensitive to oil residue build-up.

-Charlie

wont it blow oil seals if its stuck closed?

 

[phattyduck]

wont it blow oil seals if its stuck closed?

In modern engines, not so much. There is basically always a secondary crankcase vent pipe without a valve on it. In various engine loads, the PCV route and the vent route without a valve do different things. Idling and cruising, the PCV valve controls the flow from the crankcase to intake manifold to a nominal vacuum level in the crankcase to the level chosen to balance MPGs and blow-by volumes (too much vacuum draws excess oil from the crankcase to intake). The PCV valve also stops all flow from the intake manifold back to the crankcase (backfires or sudden throttle applications). The vent hose allows unrestricted flow in both directions, connected to the intake tube between the MAF and throttle body. In idling and cruise situations, fresh air flows into the engine (on the opposite head from the PCV valve) to clean out acidic combustion gasses in the crankcase. During high load situations (full throttle, etc.), that hose allows excess blowby to escape to the intake tract to be burned by the engine.

So:
PCV = flow controlled 1-way valve
Vent = fresh air source and 'overflow' vent

If the PCV is stuck or plugged, the vent can handle most of those duties by itself, though less effectively. (so, engine oil goes bad faster, lower MPGs, higher chance of oil leaks, etc.)

-Charlie

 

[lozawa]

18.42% increase in gas mileage. Changing PCV valve. Curious. What was your mpg prior and after PCV change.
2001, 216,000 miles, still original PCV valve. Guess, I'm lucky too.

 

[jnissen]

In city I regularly get 19. On the road about 24 to 32 depending on the speed. I have a muzzler installed. Has not changed since the muzzler install at about 140K miles. If you change the oil often on these vehicles you really should not have PCV system fails. I would consider changing it out if i notice the mileage change or notice the running is different.

 

[Ticket]

In modern engines, not so much. There is basically always a secondary crankcase vent pipe without a valve on it. In various engine loads, the PCV route and the vent route without a valve do different things. Idling and cruising, the PCV valve controls the flow from the crankcase to intake manifold to a nominal vacuum level in the crankcase to the level chosen to balance MPGs and blow-by volumes (too much vacuum draws excess oil from the crankcase to intake). The PCV valve also stops all flow from the intake manifold back to the crankcase (backfires or sudden throttle applications). The vent hose allows unrestricted flow in both directions, connected to the intake tube between the MAF and throttle body. In idling and cruise situations, fresh air flows into the engine (on the opposite head from the PCV valve) to clean out acidic combustion gasses in the crankcase. During high load situations (full throttle, etc.), that hose allows excess blowby to escape to the intake tract to be burned by the engine.

So:
PCV = flow controlled 1-way valve
Vent = fresh air source and 'overflow' vent

If the PCV is stuck or plugged, the vent can handle most of those duties by itself, though less effectively. (so, engine oil goes bad faster, lower MPGs, higher chance of oil leaks, etc.)

-Charlie

Thank you for that explaination...

so the systems have evolved somewhat.

I did notice on my kids car with a poorly functioning PCV, that the oil cap had that creamy color oil under it.
thats how I knew it was done, and it was bought used with some gaps in the service history.

That also concurs with your mention of oil life.
swapped out the new one and that issue went away.

cheers

 

[nysj83]

@Ticket
The alumium sleeve did not come with the new one. You would have to buy it separately if you lost one, or simply use the same old one.

@Iozawa
I had around 18MPG before change. Now it's around 20~21MPG.
I drive around NYC area most of the time so you can guess why so low MPG.

@jnissen
There was no indication or issue that my PCV was going bad. Like I stated, I just did it for preventive maintenance.
I'm sure I would've been doing just fine with old one until 200k miles with the old one as it was still 'rattle-y' when it was removed at 110k miles.

The point is, the cost and effort of replacing it is so little it's well worth doing it more often than not.
If you are 'if not broken, don't change it' person, then by all means, you can keep driving it with old one.

 

[MrRangerZr1]

I don't think a bad PCV valve will affect MPGs. It'll drink oil like mad if it's clogged.

If you don't want to change it you can clean it with plastic safe cleaner.

 

[rmyoder]

Apparently you can check the PCV function without removing it from the vehicle. I have not done this yet but plan to do so soon.

From the service manual:

At idle, listen to the PCV valve (A) with a stethoscope as you lightly pinch the PCV hose (B) with your
fingers or pliers several times. Each time the hose is pinched, the valve should click.
If there is no clicking sound, check the PCV valve collar and O-rings for cracks or damage. If they are
OK, replace the PCV valve (see PCV VALVE REPLACEMENT ), and recheck.

 

[Ticket]

Apparently you can check the PCV function without removing it from the vehicle. I have not done this yet but plan to do so soon.

From the service manual:

At idle, listen to the PCV valve (A) with a stethoscope as you lightly pinch the PCV hose (B) with your
fingers or pliers several times. Each time the hose is pinched, the valve should click.
If there is no clicking sound, check the PCV valve collar and O-rings for cracks or damage. If they are
OK, replace the PCV valve (see PCV VALVE REPLACEMENT ), and recheck.

cool trick for ones that have a hose going to them...

 

[Ticket]

so pinch B and listen...

cool!

 

[rmyoder]

Apparently my PCV is bad...I pinched and listened but no click! Will add this to my to-do list...

 

[Ticket]

Apparently my PCV is bad...I pinched and listened but no click! Will add this to my to-do list...

lol

the more I read on this forum, the more my van suffers from hypochondria.

there was a previous post on troubleshooting a squeaking sound, and now today my AC compressor is squeaking with the AC on at cold start up.

 

[rmyoder]

lol

the more I read on this forum, the more my van suffers from hypochondria.

there was a previous post on troubleshooting a squeaking sound, and now today my AC compressor is squeaking with the AC on at cold start up.

Lol just give it some time and think of something else ... hypochondriac vans usually quit complaining (and move on to another issue) if you don't pay attention to them!

 

[Ticket]

Lol just give it some time and think of something else ... hypochondriac vans usually quit complaining (and move on to another issue) if you don't pay attention to them!

LOL!

 

[phattyduck]

so pinch B and listen...

cool!
View attachment 155959

Just so everyone is clear - you need to pinch the left "B" in that picture. The one on the right likely won't do anything (that's a breather, not on the PCV line).

-Charlie