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Discussion Starter · #1 ·
Hi guys, just watched this video. Seems to be a very easy DIY to change the PCV valve. The comments below show that MPG will improve and oil burning will reduce. Sounds like a no brainer.

However, I don't want to just throw a new valve to replace a perfectly functioning old valve. So if I take out the old one and it is all clean, and I shake it and I can hear something clicking, it means it is a good valve and I can just put the old one back? If it does not, or barely, clicks, is there a way to clean the PCV?

 

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You should replace it every 100K anyway...
Carbon build up will naturally degrade its performance until it sticks closed and becomes useless.
 

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Discussion Starter · #3 ·
Ok, just finished playing with the PCV valve. It is quite interesting.

1. Taking off the 10mm bolt is not easy. The angle is awkward. I used a flex head ratchet to take if off. Putting it back on was even harder. So I used a 10mm locking flex head wrench. I am sure that using basic tools will get it done. It just is a lot easier to have more suitable tools. Also, don't lose that metal spacer/bushing/washer in the bolt hole.

2. After removing the bolt, taking the PCV valve out was not easy. It was stuck there really good. I used small and big flat head screwdrivers to take it out. Do it slowly and don't risk anything. Somebody got the valve broke inside the valve and they have to remove the valve cover to remove the valve completely. It is royal pain. So be careful.

3. The valve came out with some oil on it, not a lot. This is normal given the function of the valve. I wiped the valve clean and used brake cleaner to clean it. A very small amount of carbon deposit came out. The amount was really tiny. Given the valve is covered by oil and I have always used full synthetic oil, my belief is that the oil washed most of the carbon away. The valve did not rattle at all after the removal. After the cleaning, it rattled, but not a lot.

4. The hole beside the 10mm bolt hole is a dead-end hole. It is nothing and useless. Just forget it. The real holes are the top hole and the two big holes on the side of (and near the middle of) the valve. The top hole is connected to the intake, and the big side holes are connected to the crankcase. When crankcase pressure is high, the dirty blow-by will vent from the side holes to the top hole and go to intake. See the first attached picture.

5. There are 4 smaller holes near the top hole. They are just helpers. So I taped them up with electric tape. After cleaning, I can very easily blow through the side holes to the top hole. Interestingly, I can also blow from the top hole to the side holes. This should not happen because the valve is supposed to be a one way check valve. But if you think about, it does not hurt either. This video is quite helpful. Even though it is not directly applicable to MDX.


6. The definitive evidence of a bad PCV valve is a dirty throttle body plate. If the PCV valve is stuck, blow-by will exit from the breather pipe and mess up the plate. But I am very lazy and don't really want to bother. So I just put the old valve back on and went my merry way. There is no need to replace it. If you really got the itch to replace it, the part number is 17130-RYE-A01.

The following two discussions are very helpful

https://bobistheoilguy.com/forums/ubbthreads.php/topics/3983964/2

http://www.mdxers.org/forums/newreply.php?do=postreply&t=154618
 

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Discussion Starter · #4 ·
BTW, the manual said to listen to the valve while pitching the PCV hoses. I tried that and it did not work. I can hear nothing. And this is not surprising given that the valve is bathed in oil, and makes faint rattling when I shake it. If you ask a dealer to perform this procedure for you, they will come back to tell you that it needs replacement for sure.
 

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wow- AFTER all that discovery, effort to take out old PCV valve, you just ended up putting the old one back in?!!!!....surprising as the part is only about $25....and even more so because the STEALERSHIP charges about $100-140 in labor fee's just to take the old one out and put the new PCV valve back in!!!

well at least I learned about another useful/important maintenance item that I will have done soon (I'm at about 94K miles on my '09 MDX) :29:

*couldn't find a 2007-2014 Acura MDX specific (PCV valve replacement related) video, but did find one associated to a 2008 Honda Odyssey:

 

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Discussion Starter · #6 ·
$25 can buy a nice set of wrenches, or two nice hose pliers etc. I have so many tools that I am thinking about all the time. No way I am going to throw a working part away. Since I made sure that I can blow through the valve each way, there is nothing to worry about. To me that old valve is the same as a new one.

If someone tries to replace this valve in the future, can you please take a good picture of the valve before the job is started? After I put the valve back, I think the look is kind of funny. But I believe I have taken care of everything. So need some help to make sure. TIA.
 

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On the MDX it is easy to check if PCV is not functioning properly. Just remove one end of the hose that connected to the intake manifold. If the inner tube is covered with varnish or any oil residue, replace the PCV. A visual inspection can also determine whether PCV is bad. The bolts securing the front and rear valve cover start leaking oil (too much pressure build up).
 

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On the MDX it is easy to check if PCV is not functioning properly. Just remove one end of the hose that connected to the intake manifold. If the inner tube is covered with varnish or any oil residue, replace the PCV. A visual inspection can also determine whether PCV is bad. The bolts securing the front and rear valve cover start leaking oil (too much pressure build up).
In your opinion- would it be a fair assessment to conclude that irregardless of the actual condition of the PCV valve (let alone the absence of any related error codes, obvious symptoms etc.) on a 2nd gen. Acura MDX, replacing it at about 100K miles would be a good idea especially if one might be planning to keep the car for another 100K miles? :nerd:
 

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In your opinion- would it be a fair assessment to conclude that irregardless of the actual condition of the PCV valve (let alone the absence of any related error codes, obvious symptoms etc.) on a 2nd gen. Acura MDX, replacing it at about 100K miles would be a good idea especially if one might be planning to keep the car for another 100K miles? :nerd:
My Honda Odyssey and my MDX did not give off any error code when PCV not functioning properly. The Ody was at 60K (11yrs old) and 11 MDX was around 70K both started leaking oil through the valve cover bolt. My opinion, replace at 75K is fairly safe. It's only $30 diy.

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My Honda Odyssey and my MDX did not give off any error code when PCV not functioning properly. The Ody was at 60K (11yrs old) and 11 MDX was around 70K both started leaking oil through the valve cover bolt. My opinion, replace at 75K is fairly safe. It's only $30 diy.

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Thanks! I'm at 94K miles on my 2009 MDX and have never any had any leaking/burning oil issues or observance of any related error codes. Furthermore, I've consistently been having my oil & filter changed regularly (likely too often) with Mobil 1 Synthetic OIL (along with FRAM ultra synthetic oil filters) for most of the life of the vehicle...

*didn't even know what a PCV valve was until I saw this thread!! :laugh:

Suffice it to say- even without the immediate need to replace the PCV valve, I'm gonna have it done soon regardless- just ordered the OEM part from eBay for about $24 shipped :29:
 

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Discussion Starter · #11 ·
I have a 17 year old Toyota and I have never changed its PCV valve, even though guys at ToyotaNation routinely change it, almost for fun. As I said before, the definitive symptom of a failed PCV valve is a contaminated throttle body plate. I actually took apart the throttle body of that Toyota to clean the idle air control valve. And I saw in my own eyes that the outside of the throttle plate was pristine. So my 17 year old PCV valve is working just fine. In the end, if one is happy to throw away $25 and put a new part on, go ahead and do it. It won't hurt anything for sure.
 

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Discussion Starter · #13 ·
Could you please take picture of the PCV valve before removal? Thanks for the help. Want to see how it looks from factory.
 

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I?m laughing right now cause I?m at 140k miles and I?ve never even touched the PVC! It?s probably something I should take a look at...
heopfully you can do this your self as the stealership will charge on average about $150-$200 to replace the PCV valve (aka. a thorough BUTT RAPE!!!) for you! :laugh:
 

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Could you please take picture of the PCV valve before removal? Thanks for the help. Want to see how it looks from factory.
Will do!

heopfully you can do this your self as the stealership will charge on average about $150-$200 to replace the PCV valve (aka. a thorough BUTT RAPE!!!) for you! :laugh:
Sounds like something I heard in my other post... :laugh: at least this is something that won't cost me a whole lot to do on my own!
 

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Could you please take picture of the PCV valve before removal? Thanks for the help. Want to see how it looks from factory.


I changed my PCV valve last weeks and here the pictures of the old valve I tried to take it a part to understand how it work. The way this PCV valve works is to regulate the the amount of blow-by into the intake and the PCV valve does not completely shut close. I tried to push the inner moving part inside the PCV valve all the down (compressing the spring) until it stopped moving and I blew some air and SMALL amount of air flown out of the holes at the small end of the valve. When the inner moving part inside the PCV valve at neutral position(when the spring not compressed), LARGE amount of air flows out the holes at the small end of the valve easily. So this tells me that this PCV valve regulates the volume of blow-by air flow. This PCV valve does not close completely. The blow-by air is always flowing through this valve and the amount of blow-by air is controlled by the inner moving part inside the PCV valve.


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I changed my PCV valve last weeks and here the pictures of the old valve I tried to take it a part to understand how it work. The way this PCV valve works is to regulate the the amount of blow-by into the intake and the PCV valve does not completely shut close. I tried to push the inner moving part inside the PCV valve all the down (compressing the spring) until it stopped moving and I blew some air and SMALL amount of air flown out of the holes at the small end of the valve. When the inner moving part inside the PCV valve at neutral position(when the spring not compressed), LARGE amount of air flows out the holes at the small end of the valve easily. So this tells me that this PCV valve regulates the volume of blow-by air flow. This PCV valve does not close completely. The blow-by air is always flowing through this valve and the amount of blow-by air is controlled by the inner moving part inside the PCV valve.


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