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Old 06-09-2015, 03:55 PM
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axgordon axgordon is offline
Join Date: Feb 2010
Location: USA Maryland
Posts: 95
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I would like to share my experience with PCV mod (Long...):
The car – 2003 3.0 - Purchased February 2010 at 115000 miles from the original owner. Strictly dealer serviced from day 1 (all documented). From the supplied service records, previous owner complained about oil consumption after ~ 70k miles. Per dealer evaluation, consumption within factory specs. Previous owner disclosed to me, that he adds at least 2Qt between 10k miles oil changes.
Having extensive experience with m52 and m54 engines, I did not want to take chances with CCV and within the first two weeks of the ownership, I replaced valve cover gasket, OFH gasket and entire CCV system except dipstick tube with genuine BMW parts. The dipstick tube was removed and properly cleaned from all gunks. I cleaned a fair amount of mayo from the inside of the valve cover and all CCV lines and valve itself was badly clogged with yellow stuff.
Prior and after the service car run perfectly fine – no smoke or any drivability issues. The car is driven daily and I avoid short trips. Car always parked in the garage where temperature never drops below freezing. The oil consumption slightly increased over the past five years to ~ 1.5Qt per 2000 miles.
Over the past two years, car develop small oil leak from the rear mail seal – no drops on the floor, however heavy oil deposit on the stiffening plate and the bottom of transmission bell housing. (Planned to replace rear main seal and torque convertor seal this spring. Even purchased new genuine seals and two stage transmission jack.)
I used Slack-Tube Manometer to measure crankcase vacuum - it was normal 6” – 8”, so I did not suspect issue with inadequate crankcase ventilation. Also, no visible mayo under the oil cap.
This spring I was prepared to replace CCV components again as a preventative maintenance, but before ordering new parts, I decided to try (proof of concept) PCV mod. I followed “BavarianE39” instructions with few minor changes – utilized ends of old CCV lines to make installation completely “Plug and Play”. Also positioned PCV valve vertically. Changed oil (BMW 5W-30) and filter same day at 188900 miles on the odometer.
First impression – Noticeably better throttle response from the stop – I did not anticipate this and it was very welcome change.
This past Sunday marked 2200 miles since installation (191100 on the odometer). The oil level remained at the upper mark on the stick!!!
The stiffening plate and the transmission is bone dry!!!
I did not notice change in MPG
Conclusion – considering age and the mileage of my car I am not planning going back to stock CCV. And no more fear of hydro locking engine during winter!
If anyone interested to experiment with it – let me know and I will post pictures of my setup.

P.S. Cracked open old CCV – after 75k miles nothing clogged, reasonable amount of carbon buildup and rubber diaphragm appears to be in good shape. Checked dipstick return tube - it is not clogged. Go figure if anything is wrong with the stock system.
My son’s 2001-530i hydro locked engine in February 2013 with two-month-old CCV system. That car consistently consumed 1Qt per 900 miles before and after CCV replacement. Parked outside and driven to / from school 5 miles each way.

In response to the” Trader4” point about valve cover design – please compare attached images of valve covers from m30 (old BMW engine with basic crankcase vent system) and m54. Please note that I never took internal plates from any of these covers, so cannot elaborate on what is behind, but as you can see, both valve covers have some internal plates covering ventilation hole.
Attached Images

2012 X5 x35i My new toy
2005 X5 4.4 Her's (Retrofitted Servotronic Steering Rack)
2003 X5 3.0 Mine (Retrofitted Servotronic Steering Rack and Heated Steering Wheel)
2001 M5 Son's car
2000 540i 6sp Sports pkg, supercharged. Son's car (Sold)
2001 530i (Sold)
1999 528i (Sold)
1975 2002 (Sold)
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