how to check your PCV?

[kreigle]

quote:

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Originally posted by Leo:
Seeing that PCVs are spec'd closely to match the flow rate of the engine, are the aftermarket ones up to spec with the factory ones?

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I've tried 3 different brands of aftermarket valves and have yet to find one that even FITS my Honda Prelude. They are all too small in diameter to fit snugly in the grommet and the vacuum tube fitting is always too large for my manifold hose.

OTOH the Honda valve is $18 from the local dealer so either way, I'm F--d.

 

[yugrus]

quote:

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Originally posted by MN Driver:
While this thread is up, on the other side of the valve cover, there is a tube about the same size as the PCV tube and goes into the air intake, that is part of the PCV system too, right? Is there anything that needs checking there?

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This most likely is the breather hose. That's how the fresh clean air gets to the crankcase while the "stale" air with blow-by gasses and what not is sucked out through PCV valve by the intake vacuum. At idle there's not too much blow-by and if it wasn't for a breather, the functional PCV valve could produce quite a vacuum in the crankcase.

While changing PCV valve, it is a good idea to disconnect this hose and look for oil/deposits in it. Sometimes when the engine is worn PCV valve can not evacuate all the blow-by products, and part of the gases goes into the breather. The same thing might happen if the old PCV valve went bad, or it was too restrictive.

PCV valve itself lets certain amount of oily residue into air intake. If the breather contributes to this oil input the situation quickly becomes bad. Oil reduces octane number of the fuel and the engine tends to detonate. Oil then burns in combustion chambers and quickly carbonizes them.

BTW, my OEM PCV valve runs for about $30 CDN. It is threaded and all- metal. I'll try to clean my old one with acetone today.

 

[LubeOiler]

I was always told if it rattles its working.That is just a confirmation that the crankcase gases are going somewhere as opposed to nowhere.I clean the PCV out at 30000 if it rattles.

I remember my old Chevy with the vent tube that had a screen in it. When the screen got clogged the thing would burn oil.

 

[Ugly3]

quote:

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Originally posted by LubeOiler:
I was always told if it rattles its working.That is just a confirmation that the crankcase gases are going somewhere as opposed to nowhere.I clean the PCV out at 30000 if it rattles.

I remember my old Chevy with the vent tube that had a screen in it. When the screen got clogged the thing would burn oil.

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That had to be a 195x Chevy?

 

[brianl703]

quote:

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Originally posted by rpn453:
I've never seen an owner's manual recommend PCV replacement at a certain time.

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Ford recommends 60K. I don't know about their new cars, but my 1995 Contour said in the manual that they'd replace it for free at 60K. I didn't take them up on that offer.

 

[Gew]

Bumping this very old thread, I hope it's okey. My Lexus RX300 is throwing P0171/P0174 (lean, both banks) just about every time I refuel. I have checked charcoal canister, fuel cap, hoses, and everything seems alright. Idle is also fine and engine performance doesn't feel down on any way.

Today I unplugged the PCV and it won't rattle and I am able to blow air from both sides (tasted bad on my lips, I hope it's not cancerous) although easier from one side. I put the thing in a ultrasonic cleaner filled with brake cleaner. After 10 minutes the bowl was a black mess.

Now the thing looks brand new and the spring mechanism is working, but I'm still able to blow air from both sides. Sigh. Called the dealership here in Europe and they want $80 for this piece, said it was an old and rare OEM part. I looked it up on Amazon and it looks like the PCV is more like $8 in the US, but unfortunately shopping overseas is very expensive.

I think I'll give it one more time in the ultrasonic cleaner. This time I'll use gasoline instead of brake cleaner, like someone in this thread suggested.

 

[mk378]

It's not a check valve. At high vacuum the plunger moves to slow down the flow some, but it doesn't ever close completely.