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I did an oil change tonight, and I was tired of the top of my engine looking like an EPA disaster due to what I thought might have been a cracked CCV puck. I have an EHM, but pretty much for the last 6 months or so, no matter what I did the smell of the thing would keep getting into the AC, which also made me think there was a problem in the CCV.
So I pulled the thing off tonight and discovered a couple things when I got it apart:
There are TWO ports into the head for the CCV to connect to. Full flow is allowed between these two ports, as far as I can tell. It was getting dark, so I didn't have a chance to try starting the engine and see if one or both of these are the source of all the airflow through the EHM hose from the exit. But that leads to the second discovery.
I cleaned the outside of the CCV and found that the top of the puck is actually separate, and can be pried off with some work with a small screwdriver. Dang thing is tight. Inside the cap is a rubber bladder held against the top cover by a spring centered in the outlet that the EHM connects to. It was my understanding that the pressure in the engine was supposed to OPEN a valve, not have it permanently held open over the drain by a spring.
The airflow enters the CCV, passes through a small hole in the bottom of the large top chamber, then flows upward along the underside of the rubber bladder to the center when it can exit through the EHM with no resistance to flow at all. There is no flap / valve action here, as the top cover has no holes or spaces to allow the rubber to flex and open the drain.
I just now realized how / why this is designed this way - With the turbocharger and air filter connected to the output of the CCV, a VERY powerful suction will be created when the turbo spools. With only the small hole in the bottom of the CCV, this would function to suck the rubber bladder down and close the CCV off at the very same time that the engine is working the hardest... Presumably generating the most blowby crank case pressure? I would have thought that would create more of a problem of seals popping... But we haven't heard about a lot of that happening, so I guess not.
I'm open to suggestions about a way of designing a replaceable filter element for this, possibly involving the existing base and just replacing the cap with a taller cylinder / cap? Maybe even a way that the EHM can then be re-integrated to the intake, as it will no longer be carrying oil mist, and we can all avoid that smell entering the cabin. Without the CCV connected to the intake, that rubber valve isn't needed at all, but if we wanted to reconnect it... Then we want the turbo sucking clean air when boosting, not engine fumes that don't burn.
Thoughts?
_________________ Proud supporting vendor of LOST Jeeps TRAVELING CRD TECH. I come to you! Need help? Just ask! I've taken it apart more than most. Email jeep [at] maincomputer [dot] com - BOARD MESSAGING IS BROKEN Over 225 CRDs currently driving with my valves, timing belt, rockers, or ARP Studs. Bad noises = REALLY bad things.
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