1997 vmw 540i ccv whine

[120alexis]

I have a 1997 bmw 540i i recently replaced the ccv 2 weeks ago and today it started whining when the car decelerates i push on the diaphram cover and it stips making the noise when i let go it starts again. Any ideas ? It is a uro part. Could i probaly swith the cover with the oem one?

[edjack]

Methinks you've solved the problem.

[R Shaffner]

I have a 1997 bmw 540i i recently replaced the ccv 2 weeks ago and today it started whining when the car decelerates i push on the diaphram cover and it stips making the noise when i let go it starts again. Any ideas ? It is a uro part. Could i probaly swith the cover with the oem one?

Same thing happened to me. Easy to fix.

Along the outside rim of the CCV is a little slot that lets air flow in and out to the back (atmosphere) side of the rubber diaphragm. When my CCV was buzzing, I found that the sound got a lot louder when I reached down and put a finger over the slot (at idle). So I figured it would get quieter if I opened up another slot to let air flow in and out easier.

I took a hacksaw blade, held it with my fingertips (or you could use a small rag), held it an an angle and carefully cut a small slot in another location on the cover -- on the shoulder just like the slot that's already there. The trick is to cut just far enough to make an opening through the cover. If you cut too deep you'll start to cut into the edge of the diaphragm. (I don't have a pic but can take one if that helps.)

It took me just a few minutes and solved the problem completely. That was 2 years ago. So far so good.

[geargrinder]

Thats crazy I've never heard of that hack. If it works that's great. Is it a defect in later manufactured CCV's or something?

[R Shaffner]

Remembered that I did take a pic. Here it is. The slot I cut is just above the center of the picture. The factory slot is about 180 degrees from this, along the bottom. (My second option was to get a real BMW part. Before tossing this CCV I thought I'd try this fix first.)


CCV with slot.JPG

[120alexis]

Thank you i will have to give that a try. Cause it only does it when rpms go down.

[R Shaffner]

Clarification: The factory opening to the atmosphere side of the diaphragm in the CCV cover isn't a slot. It's a small hole, maybe 1/8 inch in diameter, along the bottom shoulder of the cover.

[JimLev]

Methinks you've solved the problem.

+10....It is a uro part.