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Old 06-10-2012, 07:28 AM
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bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
Join Date: Mar 2008
Posts: 25,236
Mein Auto: 02 BMW 525i M54 auto 130K
Originally Posted by Steve530 View Post
the air you blew into the vent hose went into the intake manifold.
Oh. < sheepish look of embarrassment >

I was following someone's advice ... and they didn't mention the engine running. Silly me. I didn't realize.

There must be three conditions:
- No vacuum (engine off) ==> Spring pushes diaphragm, upper port open --> blowing goes into intake manifold
- High vacuum (engine idling) ==> Vacuum pulls diaphragm, upper port closed --> blowing goes into oil sump
- Low vacuum (acceleration) ==> Spring pushes diaphragm, upper port open --> blowing goes into intake manifold

I wonder if we can use this test as a diagnostic for identifying a torn diaphragm in situ?

Anyway, to find out if I can 'hear' the bubbling of air into oil over the engine noise, I'll try anew (this time with the engine running and a hose to keep my face & hair away from the whirling fan); but it's going to be hard to hear the bubbling with the engine running ... so this suggested test may be moot (unless it's useful to test for a torn diaphragm).

What do you think would happen if the diaphragm were torn?

Originally Posted by Steve530 View Post
remove the CCV drain tube ... and blow through that hose.
Wow! I didn't think of that - but - that's the BEST suggestion so far (i.e., easiest) so far for testing for a clogged dipstick guide tube!

I think EVERYONE with an original CCV (even those in warm weather climes) should run that simple test!

To help them, we should identify the ID of the jumper hose that they'll need to slip onto the lower elbow of the steel dipstick guide tube. (I can measure my old hose and report back.)

EDIT: Measuring with my caliper (yes, I know, overkill), I get 0.430 inches ID, which is about 11 mm or 7/16 inch inside diameter of the original rubber lower CCV vent hose drain opening where it connects to the steel dipstick guide tube offshoot finger.

Given that, I would like to ask the NEXT person who wants to test this to connect a few feet of 1/2 inch ID stock rubber hose to the drain vent on the dipstick guide tube and to blow to see if that indicates a clogged drain vent tube BEFORE removing the tube from the vehicle, like I did.
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Last edited by bluebee; 06-10-2012 at 06:15 PM.
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