I think the idea behind the CCV is to keep the recycled gases as inert as possible to reduce NOS emmisions similar to how an EGR works. Sucks for moisture though! ;( even a small amount of atmospere let in would allow the whole thing to work a lot better. I imagine the engineers where given zero tolerance though.

A PCV is a part answer to the CCV challenge. In the US we just call them PCV systems as domestic manufactures use(d) a replaceable tube/vent/orifice that used to be a annual replacement item. In the '65 model year they were required. In 1968-70 days: intake tube in the air cleaner allows filtered air in, PCV tube vented fumes into the intake and hence into the combustion chambers. Way too uncontrolled for emissions now days. A few are still around in 2000's.
ALL the easy systems are long gone....

NOX is a byproduct of combustion (air/fuel burn). The EGR was introduced to lower the temp and completeness of the burn as NOX increases as the flame wall travels to the very end of the chamber. So they introduced a part of non combustible mix to the intake side to solve that issue for 1972+. Worked OK until someone invented the ability to measure air/fuel ratios on the fly called an O2 sensor, which allows the ratio to be more controlled across the RPM/load ranges. We can and have kicked this one around way too long as it is off topic and is only interesting to SAE geeks.

We are stuck with what the engineers dreamed up and was Federalized for the US and Euro market. It works as designed. We are the last owners (most of us) so we have to suck it up and replace/clean and keep a watchful eye out for what is mostly a winter challenge. (No I did not forget about the oil consumption issue challenge with some applications/engines. Just don't have the issue personally, so I am not expending any grey matter on the issue) :rofl:

Yeah I did. I used the smaller of the two ports on the firewall side of the intake manifold. There is only one capped port on the CCV. You can get to it in place, but you need to remove the intake box/hoses, icv, and wiring junction box

@Sroor9001, I know all about those "O2Pilot" mod and "50sKid" on youtube. I want to do a definitive mod and am glad I did this mod. Once you have all the parts (hoses, clamps, Tee), you can do this on 30 min. Very very easy mod.
I am now 500 miles AFTER the CCV Mod, zero oil consumption (used to be 1qt/400 miles).

@all: re CCV vs PCV. Both systems accomplish the same goals:
a. CC blow-by gets routed back to the Intake Manifold ---> combustion chamber.
b. Oil returned to the sump.

The method is slightly different on how the gas is routed back to the Intake Manifold:

1. CCV: the spring/diaphragm has a pre-set value, once the vacuum difference exceeds ___ in Hg (let's say hypothetically, it is 10 inches Hg), the diaphragm opens.
- Let's say at idle, the I.M. vacuum is -15 inches Hg, CC is - 2 inches Hg, now the vacuum difference is > pre-set value of 10 inches Hg: the diaphragm opens, allowing blow-by gas to enter I.M.
- So, depending on how much CC gas is being produced, the diaphragm opens On-Off to allow air ---> I.M.

- FAUCET ANALOGY: similar to you turn on the faucet: "On" and "Off".


2. PCV: there is always a flow, but controlled by the spring/pintle design.
Note the difference between Vacuum vs Flow Rate, they are 2 different things.
- The vacuum difference controls the position of the spring/pintle system.

- FAUCET ANALOGY: similar to you leave faucet "On" just a hair so there is some dripping, sometimes you turn the faucet up a bit to get more flow, and turn it down to a slow dripping flow.

Japanese cars such as Honda still use PCV and emission is as good as other mfg's.
Personally, I like PCV system better b/c it is easier to maintain.

Thanks I did this but returned back to ccv cause I got leak on valve cover gasket and oil filter housing so I've bought ccv
Tried 2 pcv valve got leaked any way I'll do oil catch can if I didn't get ccv which I preferred no vacum than extreme vacum
I hope everything is running well for you if it's too cold right now I hope my ccv withstand at least 2-3 years

And just the standard BMW braided vacuum hose worked right? I may have to finagle it in place as I have the cold weather valve so that insulation might be covering my capped port, but this will probably be on my spring to-do's - if I have to I'll remove the valve and replace hoses or valve if necessary. It wasn't a fun job the first time but I imagine a second time might be easier, maybe I'll have to get the other things out of the way like OFHG as preventative while its open.

I still am not completely sold on the PCV fix as I think it might add a bit too much vacuum to the crankcase.

Wow haven't been on here in a while and this thread has sure blown up! I am happy to report that my original pcv valve is still going strong, I sold my x5 to a good friend of mine and it has accumulated 30,000+ miles on this original pcv valve. Still absolutely no oil consumption or any issues pertaining to this mod. Also no issues to report from other people around me who have done this mod, even in these cold temps everyone has no complaints!

The vac line wasn't braided, just plain rubber (11727545323). I have the cold weather version as well. I used a scalpel and cut a small square incision into the jacket for the port. I used a picture of a warn weather valve to help locate the port.

I performed this mod on my 2.5L BMW 525i, 5 speed. Very well maintained but the oil consumption was concerning. Shall monitor. Great write up.