DIY Solution to M54-M52TU CCV problems

[Joshdub]

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.

[bcredliner]

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.

[cn90]

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?

[Fifty150hs]

Originally Posted by cn90

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.

[Sroor9001]

Hi so is that conversion make too much vacum ?

https://youtu.be/IGHvc8TGwn0

[Joshdub]

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.

[Sroor9001]

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

[Scott ZHP]

Originally Posted by bcredliner

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.

I share this opinion.

I replace the CCV and all hoses and clean out the air distribution manifold about every 60k miles. Use the cold weather version of the CCV, the insulated hoses and if you live in a really cold area - retrofit the cold weather dipstick - it eliminates the baffle that gets clogged. At the same interval, I use a can of BG Products "EPR" (aka BG109) to keep the rings unstuck. I have 148k miles on my 3.0i/M54, bought it new, and it uses virtually no oil.

[80stech]

I have 1 car on each system, but I do have a pressure relief built into my PCV conversion for instances where the crankcase might become pressurized. The PCV valve is designed to work on an "open" crankcase. The conversion kinda works but does rely on a little bit of luck and some air getting into the crankcase.

For those with the original CCCV you can get rid of the moisture build up (and freezing) by letting a little fresh air into the system. letting the engine idle for even 1/2 a minute with the oil cap off, just before you shut it off, once in a while makes a big difference, but yes, a PITA but a good test . The better answer would be to drill and tap a small hole at the back of the valve cover and install a small orifice and filter to let a little air in.

[cn90]

I am trying to figure why this mod (more vacuum in crankcase) reduces oil consumption, and I think I have the answer (any engineers in forum?).

Quick review on 4-cycle engine: Intake, Compression, Power (Explosion), Exhaust.

- Compression, Power strokes have positive pressure inside the chamber (thousands of psi), creating blow-by.
- Exhaust is kind of neutral, maybe hundreds of psi or close to 0.
- It is the Intake phase that creates suction in the combustion chamber (thus the vacuum in the Intake Manifold).

My 1998 528i M52 has no oil consumption, even at 165K miles.
My 2006 X5 M54 has brand-new CCV and drinks about 1qt/500 miles. From reading mlody post and blog (aka ElbowGrease on youtube channel), the oil ring (the bottom ring) is low-tension and has a gap of 2.5mm after some 120K miles. This gap allows oil to sneak up and sucked into the chamber during intake stroke.

- My X5 Stock brand-new CCV: when removing oil cap, there is a slight hiss but no big deal, so the vacuum is not much.
- My X5 AFTER CCV Mod: when removing oil cap, there is a moderate hiss, so the vacuum is more than stock.


When the M54 is new, the gap is small (? 0.4mm), so virtually no oil sucked into chamber.
As mileage adds up, this low-tension ring wears out, creating the gap of 2.5 mm.

Anyway, the work around CCV mod that increases crankcase vacuum reduces oil consumption.

So, this is my theory, feel free to correct me. Numbers are arbitrary strictly for discussion...

1- Stock CCV: there is not enough vacuum in crankcase (neg 16 in Hg and neg 4 in Hg = difference of 12 in Hg), during Intake stroke, the differential in vacuum allows oil to be sucked into the combustion chamber ---> oil burned.

2. CCV Mod: now there is more vacuum in crankcase, close to I.M. vacuum (neg 16 in Hg and neg 12 in Hg = difference of 4 in Hg), during Intake stroke, the differential in vacuum is not enough to drive oil into the combustion chamber ---> very little or no oil burned.

Anyway, just a theory and would love to hear from some engineer gurus out there.

- First photo is the principle of 4-cycle engine.
- Second photo is Stock vs CCV Mod.



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