Does anyone know how i can test my PCV Valve before I buy another one. Let me give you a little history as to why i think that may be my issue. A while back I was driving to work, I got a flashing Check Engine light. I took out my obd reader and checked what codes i got. I got a P0307, Cylinder misfire in cylinder 7. I went to autozone and bought a new spark plug hoping thats all it was, but it turned out not to be. I bought a replacement ignition coil from autozone since i needed to get the car operational asap. I installed the new ignition coil and voila, the problem was fixed! I then went to replace the coil cover and had trouble, so i removed the mushroom looking pcv valve to have more space and ended up breaking the plastic breather hose. I took a plastic hose from my oil filler funnel and replaced the original hose with that one. Everything seemed fine until this morning when i gassed up to pass someone on the highway and got a Restricted Performance and a bunch of codes: P1316,P0351,P0354,P0356,P0357, P0300,P0301,P0304,P0306,P0307,AND 01367!!! So i took out the engine cover and turned the car on and it seems that the hose is undergoing too much pressure under vacuum and clogging itself. I went and got a more rigid rubber hose and after replacing it, the codes and restricted performance disappeared. Instead of buying the official hose, i left the rubber one and over time, it too became soft and began collapsing on itself under vacuum. I parked the car and didnt drive it until i got the official pcv valve plastic hose and replaced it. I though all was well since the car started right and up and seemed like it was running fine, but once it got to normal operating temperature it gave me a CEL and Restricted performance message. Could it be that the PCV got damaged? How could i test that? If not the PCV, then what could it be? Thanks ahead of time guys as this car is really reliable and a beast on the road, but now shes so quiet

 

Let her get to normal operating temp. Pull the PCV from the valve cover with the hose attached. You will feel suction.
Turn off the engine. Pull the PCV. Shake it and it should rattle.
Blow through both ends. You should be able to blow the direction of the hose only. Blowing the other way shouldn't happen. If you can blow air both ways, you have failure. You can clean them fairly easy if you don't hear the rattle.

 

Thanks a bunch! I will check it this weekend when it warms up. Its currently 20 degrees out with a wind chill of 9 degrees!

 

+1 on this. Carburator cleaner works wonders in cleaning them out. I do not know on our cars but these are typically fairly inexpensive and easily obtainable/replaceable.

 

Ok so i checked the pcv today thanks to mr.wagstaff, and it would seem that it's not working correctly. When I pulled it off the valve cover there was definitely suction but when I took it off completely I was able to blow air through both ends. I also didn't hear any rattling when I shook it. I guess this means I need to get a new pcv valve before moving on to diagnosing everything else.

 

The spring and ball inside are probably just stuck open. You might try cleaning with carb cleaner first. They're usually just gunked up and clean fairly easily. You'll be good for another 50k miles.

Some folks use engine de-greaser too. As long as the de-greaser is not harsh on plastics, go for it.

The nozzle from the carb cleaner can help deep clean. I've cleaned dozens. Had to replace only one.

Use compressed air to flush it. If you don't have a compressor, use one of those cans we all use on our computer keyboards. You don't need 5 PSI of air here. There was likely an o-ring seal when you pulled. (I'm not looking at a manual right now, just assuming). Make sure you re-install that as well.

 

Thanks wagstaff! I did try that with some carb cleaner and mass air flow cleaner. I reinstalled it but the same issue is present. Based on what happened before with the replacement hose collapsing on itself under vacuum, Im thinking that maybe some sort of permanent damage happened to the pcv valve causing all of the codes?

 

Typically, you would find code P0171, P0174, but first things first. The collapsed Positive Crankcase Ventilation valve hose may have created a vacuum leak. You should check all lines for vacuum leaks. If you know the PCV to be defective, you can now replace it and eliminate it as a possible cause. Try those first.

Regards
Sean

 

So reviving this post once again. Its been a while since Wagstaffs last reply (Thanks for the info!) My baby got rear ended by some jack *** and so it has been in the shop getting body work done. Now that the body work is almost complete, i am having them look at the engine trouble I have been having. I will have them check for vacuum leaks. Just thought I would update everyone, and once a solution is found I will definitely report back!

 

UPDATE-So the mechanic has not found any vacuum leaks and has changed 5 out of 8 ignition coils. According to him, its running a lot better but I wont know till later today when I go pick it up. Furthermore, he tested the PCV valve and said its not defective. Lets see what happens, its been more than 2 months without my girl and i miss her!

 

I am aware this is a 4 year old thread. But replacing so many coils, and telling the customer he "tested" the PCV (not a PCV valve which everyone says and is redundant) all seemed a bit off to me. Would have liked to hear how that worked out.

I know it's not always practical to report back on the final outcome on these, but it can be so disappointing for the forum member looking for a solution. I am positive that I am guilty of this same kind of infraction, so this is not about casting blame or criticizing. It is more about suggesting to all of us to try and circle back and provide a quick summary of how things panned out, good, bad or indifferent.

Otherwise it can be like reading a book that you identify with the main character, living through their situation and conflict, only to find the last 3 pages have been ripped out of the book! Arrrggghhh! This just reminds me that I have to do better as well.

What do you say folks? Can we give the readers a "happily ever after" -and if that's not the case, then some kind of ever after?

 

In addition to Blairwares comments, our PVC Valves do NOT rattle if they are okay or fail to rattle if they are U/S; they simply do not rattle at all.

 

FINALLY! Someone put the "shake it and if it doesn't rattle, replace it" (with another one that also doesn't rattle) to the annals of urban legend - they never say when to stop replacing them!

There is no "spring and ball" in these breathers, and while there IS a diaphragm in there, I have yet to find one that restricts air in either direction when pulled off the car. The one in my current car was wide open in both directions, so I bought one on spec. Surprise! Same exact behavior. I assume that SOME pressure conditions must cause the diaphragm to close, perhaps positive pressure in both directions, such as an abrupt throttle close, or the opposite condition with negative pressure on both sides.

Theory is fun, but a)does nothing to explain the presence of oil in the breather and hard plastic hose running to the throttle body and b) does not tell me what condition to look for to diagnose if it is working as designed or failing.

If anyone can point me to a proper explanation of crankcase ventilation for the AJ34 Engine (or any of the 4.2 Liter V8's - the 4.0 liter engines vent the engine a bit differently) I would be eternally grateful.

The forum is a great source of information on our cars, but it is the internet, with just as much conjecture, "expert wrong opinion, and downright misinformation as any other place. Fortunately it is often self-correcting by members with real experience. Stay vigilant! If you SEE BS, CALL BS!

 

EDIT: In the interest of staying civil, I've updated my comments below:

Please. No need for hyperbole. The original OP was given 3 tests for the PCV, rattle was one and common practice for years, not urban legend. So what if there's a diaphragm replacing the spring and ball. Two other tests were provided. So feel free to call my comments, or anyone else's, BS but going forward, it would be more helpful if you contributed in a polite and adult manner.

Further, like most people, I don't mind being corrected if I misstate anything. My goal is to help others and get help, not lead people off the path. You could have been more diplomatic in calling out my (or anyones) error and simply stated that while the test is valid for many models, it isn't for our cars. There is no need whatsoever to attack others who try to contribute.

 

The X350 crankcase venting system may have been a mystery even to the writers of the service documentation, given the differing terminology and descriptions in various documents. Here are a few examples to demonstrate what I mean.

The 2004 Technical Introduction refers to "Oil Separators":





The Workshop Manual refers to the component on the right bank as a "Positive Crankcase Ventilation (PCV) Valve":




And on the left bank a "Crankcase Vent Oil Separator":



Here's how the Workshop Manual describes the PCV system:



The Electronic Parts Catalog has no listing for a PCV Valve, but rather a "Crankcase Vent":




I suspect that the "PCV Valve" on the X350 is actually not a valve at all, but an oil/air separator designed to reduce the volume of oil drawn into the air intake.

Thoughts?

Cheers,

Don

 

I apologize, and do so profusely, if my comments were taken as an attack. I was, if anything, perhaps insensitive, but in reality (which rarely cone through in textual exchanges) I was trying to be humorous. Obviously successfully.

My frustration is perhaps evident, and you are not the first, and I am sure not the last to suggest shaking the PCV, as it is indeed a valid test for conventional valves. The fact is I don't know what test is valid for the AJ34 engine breather.

I begin to suspect that this is not a PCV at all, but simply a breather, with the secondary task of being an oil separator. It is after all hard to vent a crankcase without the effect of oil egress, unless you design a series of tracts, lovers or channels to keep the oil where it belongs. A simpler way may be what Jaguar was after.

So my question becomes: what amount of oil, if ANY is acceptable in this valve (I would think the answer might be "some", a very scientific term, that you can determine if it is operating as designed by pulling out the "some oil chart) and comparing your some with the acceptable level of some on the graph.

Likewise, how much is a acceptable in the tube that runs to the throttle body. Here I would expect to see "none" as the acceptable level of oil. Now, when either of these conditions are not met, what then is the correct test? My "NEW" valve, and I will freely admit my cheapo-meter caused me to select a non-oem, after previous experience, appears to work identically to the "failing" valve, when checked with the suggested tests. Not just by you, but everywhere I have looked to date.

Again, apologies to you, and the forum members, for lack of diplomacy, or just being an ***. It's the frustration in finding useful info speaking. I am (I hope) not the ungrateful, ungracious type that my post seems to indicate.

 

Don,

I have reached a similar conclusion after finding my brand new replacement appears to allow the same air volume in either direction.

I need some help. It's not an emergency, and it's not causing issues that I can determine. But I want it to work as designed. The trouble is determining what that design is.

I suspect I have a stuck open, failing or dirty injector or several. Restarts within 10-15 minutes are fine. Over an hour is fine. 20 minutes to perhaps an hour I have a bad stumble, stalling and it can only be cleared by a few throttle stabs carefully applied to get it past this.

Injectors with a tiny bit of blockage, leaping them open would cause leaking into a cylinder, and give this effect. I had it on my previous X350 starting at 160k miles and here it is on my current one at 100k. Does this seem like a likely cause? I can get past it and the car runs 100% under all other conditions, with only a very rare throttle body bug (the one that trips "Engine Systems fault,DSC not available, Parking Brake Fault" - which has happened perhaps 3 times in 18 months.

I do nor relish the idea of pulling injectors off for analysis and cleaning. This is how I stumbled (pun intended) onto the crankcase ventilation strangeness.

I will run a good injector cleaner and hope for success, but what else is good to consider? What's the cleaner that Jaguar dealers use? Is it substantially better than say, Chevron Techron, at a high concentration?

Thanks to all for any suggestions.

 

No worries. It's in the rear view mirror now. My original comments 3 years ago were based on generic experience and without the benefit of a service manual. Don has posted detail and an interesting question. There are other questions on this forum about a catch can as well so you're certainly not the first or the last with this question. I've been away from the X350 too long and don't have the benefit of looking over the engine.

 

I am rarely accused of brevity, but have often get TMI comments. I just like to supply all the known data upfront, vs. piecemeal increments.

Don's contributions are really good, even if the inconsistencies he pointed out are annoying. I one passage, the have descriptions of the right and left breathers reversed.

Another interesting bit, is the references to pil separators in the valve covers, which are referring to the baffle at the opening for these hoses/valves.

"each valve cover oil separator consists of wire gauze packed into an open ended enclosure in the top of the cover.

The key to this is in the "full load" and "part load" breathers. Don is something between a magician, a super hero, and a librarian on steroids in the way he locates, and provides manufacturers documentation. He is so good, that he can show us ALL the things that Jaguar has said on the subject, even when they contradict themselves.

Okay -last question (for this post, lol): The details Don provided brought up something I have been wondering. The "PURGE" system mentioned. I seem to recall there is a charcoal canister in the left fender, down by the windshield wash fluid container. Both of my X350s have produced LOUD clicks when that purge valve cycles.

Don. Can you point me at some detail on the purge operation, and troubleshooting. I dont know that mine is broken, functionally but that loud "CLACK" does not sound like a great thing, and I would like to make it quiet.

THANKS!

 

Deleted my question. Found a thread that clears some things up for me anyway:

https://www.jaguarforums.com/forum/x...-193136/page2/