Oil Catch Can project

[Ricky Bobby]

Originally Posted by davintosh

I've been doing some more thinking (uh-oh...) on this problem, and it seems to me the biggest problem is when the valve freezes and causes oil from the dipstick tube to get sucked into the intake. In reading through the records on my X5, that's happened twice in its history; a mess I really, really, really don't want to have to deal with.

There are other symptoms that point to a problem with the CCV system, but IMO the oil-to-the-intake failure mode is the worst that can happen; getting the system to work as it's designed while avoiding the worst-case scenario is probably the ultimate solution. That would keep the vehicle from being disabled and allow some time to diagnose and deal with the problem.

So, if I'm going to modify the system to avoid this scenario, might the best solution be something to keep the oil from being drawn up from the dipstick tube? Maybe route the drain hose to another location that isn't submerged in the oil sump... Or put a check valve in it to keep the oil from flowing upstream... Or put a catch can between the CCV and the dipstick tube with a vacuum-operated valve that only allows oil to flow back to the crankcase when the engine is off.

Personally, I like that last option best. Any others I'm missing?

From what I gathered, most are neglecting to replace the dipstick guide tube with the cold weather (single walled and eliminated the double wall design) version that came out around 2008/09 or so, as evidenced in the SIB from March 2009:

http://chrisparente.com/Images/530/CCV-SIB110803.pdf

I have seen a lot of threads about updating the CCV to cold weather version, and cold weather hoses, but not many threads about also including to utilize the cold weather dipstick tube on their install, in CONJUNCTION with the insulated valve/hoses.

My guess is that most are looking to get their X back on the road quickly with the least possible cost, and spending $140 on the cold weather dipstick tube is not cheap, it is nearly the cost of the entire Cold weather CCV valve and hoses in itself.

But clearly, BMW came out with the cold weather updated dipstick tube for a reason, and it states in the SIB that if the cold weather valve and hoses are already installed, to only install the new guide tube, they must work together to keep the system functioning properly.

Personally I ordered the cold weather tube with my new insulated CCV and hoses and will be doing the complete job in the coming weeks. Wish me luck.