- My CCV was overhauled recently, all BMW parts so it is brand-new (also cleaned the dipstick housing channels, which were not blocked). Car still consumes 1qt/500 miles.

- I am looking for long-term report on the mod.

- I may do the mod today and report back in 500 miles (another month) re oil consumption.

cn90
This is my experience with this mod:
2003 X5 3.0 Auto
Mode installed - 188k miles
Current odometer - 212k miles
Oil consumption before mode - 1QT / 1200 miles
Oil consumption after mode - 0.5QT / 6000 miles
Engine runs perfectly. No codes!

Thanks axgordon,

You convinced me, I am taking the thing apart and go to Home Depot today to get all the odds and ends.

QUESTION: I don't plan to use the Duralast PCV Valve (which is basically one-way valve with the spring inside to allow air to be sucked in at certain vacuum value) simply b/c I am afraid if the PCV is ever stucked closed, the crank case pressure will be very high and some seals will be blown, with the RMS being the worst to repair.

So, who uses Duralast PCV and who does not?

cn90, have you read the thread where people add a vac line from the capped off port on the CCV to a capped off port on the back of the intake manifold?

I did and it reduced my consumption from 1qt per <1k miles to about <.25qt per 1k (averaged over the past 4k miles). I also have some seeping somewhere.

The majority of those that do some type of modification or workaround have a CCV system that is malfunctioning, in need of repair. IMO, if there is excessive oil consumption with a properly operating CCV system something else is the core cause.

Based on the mileage most of us have on our X5s it is quite likely we have or will experience CCV issues. I think the best fix is to clean or replace the CCV components rather than modify the system. If there was no excessive oil consumption for say the first 50,000+ miles I don't see the logic that the system is the problem and should be modified.

Oil consumption due to a faulty CCV system is often corrected by replacing the oil separator flap. In extremely cold areas there is a cold weather modification from BMW to address the freezing potential.

Engineering aspects of CCV (mod vs Stock)
 

OK,

I am doing the BavarianE39's mod as we speak.

I am trying to understand why this mod works b/c:

1. I went to Autozone and got the Duralast PCV valve, I just double-checked the design:
a. Blew one way (toward I.M.), it flows.
b. Blew the other way, no flow.
Nothing special, this is the design of the PCV valve, which is basically "one-way street".

2. I also have a BMW CCV Valve lying around:
- Blocked the oil return port.
- Blew at port #2, air came out port #3.
- Blew the other way, no flow.

Don't get me wrong, I am doing the BavarianE39's mod but...

From an engineering standpoint, there is virtually no difference in the 2 designs (Mod vs Stock).
See photo below: vapor + oil is still sucked into the Intake Manifold, so why does this mod work?

The difference between the CCV and the PCV mod as far as I can tell is that the CCV separates oil from the crankcase vapors and sends it back to the crankcase. The PCV mod sends oil to a catch can. I had my CCV replaced when it went bad and have had no issues with it since.

Hi so is that conversion make too much vacum ?

https://youtu.be/IGHvc8TGwn0

cn90, does the PCV mod allow for more crankcase vacuum? If so, maybe it works the same as adding the extra vac line to the CCV port. Probably has to do with the low tension rings.

But you know I got leak in valve cover gasket and oil filter housing with this modification so I'll go with ccv better not to ruin my gaskets just done few months ago :(