2014 Audi Q5 crankcase pressure
I replaced the PCV(?) valve on this vehicle(the one on top of the valve cover) twice in the last year. The first time I replaced with aftermarket and it failed in 3 months. Then I replaced with VW# …AK from SSF. We called Audi and they claim that is the latest part number. I also had to replace the upper timing cover, because the seal was blown out.
9 months later and the vehicle is back. The seal on the upper timing cover is blown out again(leaking oil,sucking in air)
Now I have a manometer(didnt before) and am getting a fluctuating reading between 89-100 mbar at the oil cap. Ive only used this tool 3 times,but have never seen the numbers fluctuate like its doing.
Using a "known good" list I got from this site, apparently 89 mbar is normal for this engine. However, why the fluctuation?
After digging a little deeper, I found that this vehicle has an oil separator(more PCV?) located on the lower left side of the engine ,under the mount. Will this cause an increase in crankcase pressure, or do I simply have a bad 3rd valve.
Smoke check system for leaks , if it is a problem with the oil separator it will be leaking smoke. The other thing that happens on these engine that causes the lean condition is the Purge valves will get stuck open intermittently causing a lean condition. Try crimping the rubber hose that goes to the purge valve to see if your STFT goes towards normal value. Don't forget to check for oil leaks…
To Rich's point on the rear crankshaft seal we have also had significant vacuum leaks at the rear main and I have seen them be the route cause of other seals failing prematurely. Spray some brake clean up into the bell housing and see if you idle changes or if you can drive your STFT. Good luck.
Yes the lower separator will affect crankcase pressure. Purge valve will cause lean code but it won't cause your seals to blow out. I would smoke test it to verify that the rear main seal is still in tact (it will smoke from the bellhousing) and then go for the lower separator replacement.
Rudy - a bit of fluctuation is normal and OK with the crankcase pressures as you test more of them you will see that more often... Your pressure is in line with known good valve. As others have said check the rear main seal they get sucked apart with failed regulator some times. I usually like to put the smoke into the dipstick tube for checking the rear main seal just seems to be a bit quicker…
Bill- The pressure will get as high as 100mbar, is that still considered good on this? Also when I say it fluctuates,it really fluctuates. Its can be as low as 89 mbar, but then will cylce between 95-100mbar, then back down to 89 and so on and so on.
Rudy - I dont think i would be to concerned about 100 mbar and i cant see that causing the seal to blow out. I was initially mistaken about your post and thought you still had mixture/lean issues... Sorry. I have not personally experienced the upper timing cover seal failing as a result of crankcase pressure - i have seen many rear main seals...
Bill- Ok thanks. I do have lean mixture still,but that wasn't my primary concern, as I know it to be from the t-cover.(there could be other sources,but that is my known bad for now) On a side note, I created a large vacuum leak to see how bad it will affect my mbar readings and the readings went very low(40mbar) and begin to fluctuate from there. I surmise that the air leaks I have now are…
so what brands did you use the last time around? aftermarket cover and seal? you really need to use genuine. I havent had one come back when doing so.also that number doesnt work in ssf, imc or world pac.
We had an 06 a4 2.0 with same issue. We found a breather hose from valve cover to turbo that had a check valve that wasn't working , causing a vacuum leak. Not sure if yours has this same hose. It was a metal type hose.
Elias- That number is a VW number directly off of the part. I dont know how SSF lists it. The cover was a Victor Reinz cover from WP.
To clarify, Im not so much concerned with the lean codes (Its obviously drawing air from the timing cover)as I am with the fact that the timing cover seal has blown out again. I would like input on what you all think could cause that?
There is a check valve built into the CCV valve that blocks the turbo boost pressure from entering the crankcase, but since you replaced that already it's not likely to be bad. It's easy to check though. Just disconnect the plastic flex tube at the intake manifold and blow into it with your mouth. The check valve should not let any air into the CCV valve. The check valve should close as soon as…
Steven- Informative, thanks. Im waiting on a tcover from the dealer, then I will drive it as you suggested. (Im surprised you and Bill Kenel haven't run across more of these t-covers causing lean conditions. Ive replaced at least a dozen or so for setting lean codes on these 2.0t engines.)
I had a high pressure pump leaking gas into the crankcase that was eating up pcvs and seals you could smell gas when you pulled the oil cap
Am I reading that you have 89 mbar of pressure or 89 mbar of vacuum? Yes I know that vacuum is pressure below atmosphere pressure. Does the idle fluctuate when pressure fluctuates?
Well, I drove with my vac gauge and never registered more than 1 psi(less actually) of crankcase pressure at all driving conditions. Also had 3 inHG at idle, both measurements were taken at the oil cap. I could find no discernible reason for the timing cover seal to become compromised, yet again. I replaced the entire cover with a new one from Audi, my fuel trims adjusted from +45 to 3(LTFT)…
Rudy, a nother post was just closed on a different website and the fix was a genuine cover. The other tech tried a rein and then a different brand only to find the dealer one was the correct fit.