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Before doing this job on my LS 460, I read everywhere that replacing the PCV valve required removing the intake manifold. After doing it myself, I can confidently say that is not true. The entire job took about 30 minutes and only required a 10mm 1/4-inch socket and an 11-inch pair of long nose pliers.
To access the PCV valve, start by removing everything leading up to the throttle body, which is mostly held on with 10mm bolts. Once you remove the throttle body, disconnect the upper portion of the PCV hose. On the right side between the manifold and the timing cover there is a piece of foam insulation. Remove that foam (it may tear if it’s old), and behind it you’ll see the PCV hose running down to the valve. Use the long nose pliers to reach in, compress the clamp, and slide it back, then pull the hose off. Be careful here because these hoses get brittle with age and can easily crack. I strongly recommend buying a new PCV hose from the dealer beforehand just in case.
Once the hose is off, the PCV valve is exposed but still recessed. Using the long nose pliers, find an angle that allows you to turn the valve counterclockwise. It should loosen with moderate pressure. If it feels like you’re forcing it, reposition your grip and try again. After breaking it loose, you can usually finish unthreading it with your fingers. When installing the new valve, start threading it in by hand and turn it as far as possible before switching to the pliers. Only snug it down lightly. Do not overtighten because the threads are plastic and can be damaged easily.
That’s it. No intake manifold removal, no special tools, and no complicated disassembly. Just patience, the right angle with the pliers, and about half an hour of your time.
How did you know that the PCV valve was bad and needed to be replaced? Did you use an OEM valve?
Yes just like that.
Knowing how it’s bad? Theres no guaranteed way to know but theres definitely signs, on mine I had an absurd amount of oil burning every 500 miles, and my oil light coming on after 1000 miles(below the limit). On top of that I had a slightly shaky idle. I had just replaced every pan gasket in the engine so it pretty much isolated the cause. What happens is a jammed PCV stops crank case pressure from being released, if you have old gaskets it will build enough pressure to get through your gaskets eventually causing oil leaks. Mine just being resealed forced the oil past the piston rings causing the burning. If left unchecked it will also get oil debris onto your cats, mine now has p0420 since it was left too long. Its a cheap part but can cause a lot of expensive headache.
& yes all OEM, from the PCV valve ($20) to the PCV hose ($17 online). I do not recommend non OEM parts as they are likely to fail much sooner, and usually not as efficient.
The issue isnt extentions but the socket size required. Its a 22mm just to get around the PCV nut, and that size socket does not come close to clearing in between the timing cover and manifold.
Highly doubt it. I dont see any deep socket 22mm fitting the area. You are more likely to strip the bolt or damage the manifold if you tried to force it to fit.
the problem with the socket (and I have done this several times) is it has a tendency to break the nipple off the PCV valve when pulling it off because of the angle.
I see your point, but I am not sure it it's black and white like that. On most vehicles I know, PCV valves accumulate crud over time and may become partially blocked, even if there is no underlying problem.
The point is they are cheap, so replacing them in high-mileage cars may be good preventive maintenance, assuming you can reach them easily.
Changing the pcv isn't going to make any difference unless it's plugged and if it is then you have a larger problem.
Originally Posted by chrispap
Does this matter if you are replacing the PCV valve? Isn't the real question whether you can install the new one intact?
The original PCV valve was completely seized with hardened oil deposits and not functioning. A stuck PCV directly affects crankcase ventilation by preventing proper metered flow, which can increase crankcase pressure, reduce ring sealing efficiency, and contribute to oil consumption.
Replacing a failed PCV does not “add power,” but it restores the system to its intended operating condition. If the original valve is not functioning, drivability and idle quality can absolutely improve. In my case, idle smoothness noticeably improved immediately.
Regarding installation, the only challenge was access. But the valve threads in and out normally with light pressure. As long as it’s not forced and you take your time, it installs cleanly without damage.
Whether replacing a PCV makes a difference depends entirely on whether the old one was operating correctly. At 255k miles and physically seized, mine clearly was not. However they are wear and tear parts a clogged pvc usually does not indicate a deeper problem.
Before doing this job on my LS 460, I read everywhere that replacing the PCV valve required removing the intake manifold. After doing it myself, I can confidently say that is not true. The entire job took about 30 minutes and only required a 10mm 1/4-inch socket and an 11-inch pair of long nose pliers.
To access the PCV valve, start by removing everything leading up to the throttle body, which is mostly held on with 10mm bolts. Once you remove the throttle body, disconnect the upper portion of the PCV hose. On the right side between the manifold and the timing cover there is a piece of foam insulation. Remove that foam (it may tear if it’s old), and behind it you’ll see the PCV hose running down to the valve. Use the long nose pliers to reach in, compress the clamp, and slide it back, then pull the hose off. Be careful here because these hoses get brittle with age and can easily crack. I strongly recommend buying a new PCV hose from the dealer beforehand just in case.
Once the hose is off, the PCV valve is exposed but still recessed. Using the long nose pliers, find an angle that allows you to turn the valve counterclockwise. It should loosen with moderate pressure. If it feels like you’re forcing it, reposition your grip and try again. After breaking it loose, you can usually finish unthreading it with your fingers. When installing the new valve, start threading it in by hand and turn it as far as possible before switching to the pliers. Only snug it down lightly. Do not overtighten because the threads are plastic and can be damaged easily.
That’s it. No intake manifold removal, no special tools, and no complicated disassembly. Just patience, the right angle with the pliers, and about half an hour of your time.
PCV valve change the easy way
