# Does my '04 4-cyl have a PCV valve?



## jerryp58 (Jan 6, 2005)

If so, where is it?

I bought some parts to swap out at 25k (oil change, fuel filter, PCV filter element, PCV) and Courtesy Nissan had a PCV listed for my '04 4-cyl, but I wasn't able to find it. It's not on either end of the hose going from the valve cover to the air cleaner (where the PCV filter element -- white cotton like filter).

I'd appreciate any info.


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## nissanmadness (Sep 18, 2006)

jerryp58 said:


> If so, where is it?
> 
> I bought some parts to swap out at 25k (oil change, fuel filter, PCV filter element, PCV) and Courtesy Nissan had a PCV listed for my '04 4-cyl, but I wasn't able to find it. It's not on either end of the hose going from the valve cover to the air cleaner (where the PCV filter element -- white cotton like filter).
> 
> I'd appreciate any info.


Mine was on the right hand side of the engine block. I was able to get at it by removing the inner wheel well flap or splash guard.


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## littlefish (Jul 1, 2006)

Just a suggestion - you can do what you wish. If you are going to be working on your truck, please invest in a good quality shop manual. The manuals generally show all the major components, relay locations, troubleshooting guides, brake repair guides, fluid capacities, etc. I always bought one for every car I have owned and they have paid for themselves many times over. Just a thought... Best of Luck.. Littlefish


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## jerryp58 (Jan 6, 2005)

littlefish said:


> Just a suggestion - you can do what you wish. If you are going to be working on your truck, please invest in a good quality shop manual. The manuals generally show all the major components, relay locations, troubleshooting guides, brake repair guides, fluid capacities, etc. I always bought one for every car I have owned and they have paid for themselves many times over. Just a thought... Best of Luck.. Littlefish


Well, I bought the '04 Service Manual. It has a couple of references to the PCV valve and a couple of diagrams. None of it seems to be helping me. The references say to remove the PCV from the "breather separator"; OK, what's that? One diagram shows the PCV valve in the end of a tube (the other end of the tube isn't shown); that doesn't help. The other diagram shows what appears to be a generic crankcase airflow. It appears the PCV should be in line between the valve cover and the throttle body or the air cleaner assembly. That's where I was looking for it. Actually I looked for any sign of it coming from the valve cover and any sign of it going to the air cleaner assembly or going to the intake manifold (I didn't examine the underside of the intake). I couldn't find a trace of it. And, like I said in my original post, I thought I changed what was called the PCV filter element (white cotton-like filter inside the air cleaner box. I would have thought the PCV would be on the other end of that hose that connected to the valve cover, but all that was there was a nipple going into the cover. Guess I'll poke around some more, but I would have thought a relative common, simple service item would be somewhat noticeable and would be shown clearly in the manual as a maintenance item (the maintenance section of the manual only refers to the PCV filter replacement).


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## jerryp58 (Jan 6, 2005)

nissanmadness said:


> Mine was on the right hand side of the engine block. I was able to get at it by removing the inner wheel well flap or splash guard.


Do you have the 4-cyl engine? By "right" do you mean the passenger side? Any chance you could get a picture of it? Or tell me where the other end of the hose is?


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## Z_Rated (Apr 29, 2006)

Passenger side and it is not easy to get to. I suggest leaving it unless you are having a problem or are doing some repair which would allow you easy access to it. The PCV valve is not worth the effort just to change. Now given I'm comparing yours to my '91 KA24E which I just kept the filter in the air cover clean along with other routine maintenance to keep sludge in check. Z


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## littlefish (Jul 1, 2006)

This might not help, but the white filter in the air cleaner box is where the clean filtered air goes thru before going into the crankcase. The vacuum that draws it thru is intake and is regulated by the PCV valve. At least you found 1/2 of the puzzle for the PCV air flow route. Best of Luck...Littlefish


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## himilefrontier (Jan 21, 2003)

I replaced mine, but it wasn't fun. It is located below the power steering pump and behind the altenator and is plugged into it's own seperator that attaches to the front timing cover ( it's a black box). Even having loosened and removed both of them, replacement was no picnic, and it took me 2 hours to do it. The thing is, it is almost impossible to even touch it, and you will need to be good with a screwdriver to both get it out and on again. I replaced mine at 235,000 miles and it was original( I am the original owner and have done 98% of all the maintenance and repairs). I think I did it because I had to replace the short heater hose and the coolant bypass hose which are both in there too.( If you have an older KA truck, you may wish to replace these oft-overlooked hoses as mine sprung a leak in a most inconvenient time). I also degreased and scrubbed behind there at that time as a front seal leak had caused excessive grease buildup in there which is what had killed the bypass hose.The breather is in the air filter lid encased inside a small trapezoidal white plastic box in the rear corner closest to the valve cover.It seals to the lower air filter housing via a rubber ring.


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## nissanmadness (Sep 18, 2006)

jerryp58 said:


> Do you have the 4-cyl engine? By "right" do you mean the passenger side? Any chance you could get a picture of it? Or tell me where the other end of the hose is?


Yes, right side=passenger side. Himilefrontier has the answer, read his last post. It is a pain in the you know where to get at. Lotsa luck.


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## jerryp58 (Jan 6, 2005)

Thanks all. At 25K, the PCV valve is probably fine. On all of my previous vehicles, the PCV was usually a piece of cake to change, not a PITB, which is what this one sounds like. Is there a PCV error code (like EGR) that shows up on the computer if there is a problem with the system? If so, I'll just wait for that day I think.


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## Win lowe (Dec 15, 2006)

jerryp58 said:


> Thanks all. At 25K, the PCV valve is probably fine. On all of my previous vehicles, the PCV was usually a piece of cake to change, not a PITB, which is what this one sounds like. Is there a PCV error code (like EGR) that shows up on the computer if there is a problem with the system? If so, I'll just wait for that day I think.


Jerry, I would make the effort to change out that PCV valve at the recommend time. When the PCV valve gets blocked up it causes pressure buildup in the crank case and that will make the crank seals to start leaking.  good luck


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## nissanmadness (Sep 18, 2006)

jerryp58 said:


> Thanks all. At 25K, the PCV valve is probably fine. On all of my previous vehicles, the PCV was usually a piece of cake to change, not a PITB, which is what this one sounds like. Is there a PCV error code (like EGR) that shows up on the computer if there is a problem with the system? If so, I'll just wait for that day I think.


Oh well, we tried. I've found it was easier to remove the R/F wheel and then the inner splash guard to get at the pcv valve. You'll probably be alright for now, try again at 50k.


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## jerryp58 (Jan 6, 2005)

Win lowe said:


> Jerry, I would make the effort to change out that PCV valve at the recommend time. When the PCV valve gets blocked up it causes pressure buildup in the crank case and that will make the crank seals to start leaking.  good luck


Well, I figured 25K was early but since I was doing a little PM anyway I thought I'd change the PCV valve. Interestingly, I just looked throught my service manual (on CD) and I see no reference to changing the PCV valve. The PCV filter should be changed every 30k miles (the hard copy service & maintenance booklet I received with my truck confirms this), but there is not mention of replacing the valve all the way out to 120k. If Nissan has that much confidence in the valve, I just may leave it alone.

Also, I thought this footnote on the PCV filter was interesting:

(2) When the filter becomes clogged, the vehicle speed cannot be increased as the driver wishes. In such an event, replace the filter.

I think I'll search around tomorrow and see if there's any reference to an ECU code in the event the PCV valve develops a problem.


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## jerryp58 (Jan 6, 2005)

nissanmadness said:


> Oh well, we tried. I've found it was easier to remove the R/F wheel and then the inner splash guard to get at the pcv valve. You'll probably be alright for now, try again at 50k.


I won't forget this technique. At 30k (when I change my oil again), I'm going to see if I can get to the PCV. It it looks terribly difficult and I have the need to change the PCV or if I have the need to remove the splash guard for any other reason, I'll go that route. Thanks.


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## nissanmadness (Sep 18, 2006)

jerryp58 said:


> I won't forget this technique. At 30k (when I change my oil again), I'm going to see if I can get to the PCV. It it looks terribly difficult and I have the need to change the PCV or if I have the need to remove the splash guard for any other reason, I'll go that route. Thanks.


I want to mention one more thing. That little white pcv filter in your air cleaner housing. Go back with the factory filter. The aftermarket filters are too thin and the cavity in which that little filter sits will fill up with oil. The factory filter is much denser and controls the breathing rate to specs.


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## jerryp58 (Jan 6, 2005)

nissanmadness said:


> I want to mention one more thing. That little white pcv filter in your air cleaner housing. Go back with the factory filter. The aftermarket filters are too thin and the cavity in which that little filter sits will fill up with oil. The factory filter is much denser and controls the breathing rate to specs.


Thanks. I think I'll do that. I bought one from my local auto parts, and you're right, it was maybe 1/5 the density of the factory filter.


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