Volvo Owners Club Forum - Vacuum Problem?

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Tim xc70

Dec 12th, 2021 12:56

Vacuum Problem?

Hi,

I have posted this on a XC70 specific forum, but thought I might try to widen my search. I have a strange noise from my 2011 D5 in my XC70 and I suspected it was a vacuum issue. I removed the pump and replaced the seals but it is still the same.
With the brake booster pipe disconnected from the vacuum pump and the hole blocked I get a steady strong vacuum reading, but with the pipe connected, the vacuum meter needle flicker's So indicating a fault in the booster or pipework in that direction.
On the other hand, the popping/rattling noise is strong when the hole is blocked with the steady vacuum, and vanishes with the brake vacuum line removed from the vacuum pump.
Is anyone able to suggest what is going on? The two scenarios seem contradictory.
Link to how it sounds:
[YOUTUBE]https://www.youtube.com/watch?v=deql5fLjHXY[/YOUTUBE]
Cab anyone suggest what it might be?
Thanks,
Tim.

Tim xc70

Dec 18th, 2021 14:13

Solved

Tiny nipple in the non return valve had perished. Replaced and now sounds perfect!

Kattten

Jan 15th, 2022 22:26

I have a similar issue on my D3, where is the nipple located? And did the nipple help any other than sound?

Father Ted

Jan 16th, 2022 10:46

Second request for "nipple" location. I have a D5 XC90 and have the noise associated with vacuum issue, but no noticeable vacuum issue. Be nice to resolve this.

mr tickle

Jan 18th, 2022 10:32

Quote:

Originally Posted by Father Ted (Post 2800266)

Second request for "nipple" location. I have a D5 XC90 and have the noise associated with vacuum issue, but no noticeable vacuum issue. Be nice to resolve this.

Third request for "show me your nipples" please

I have the popping sound if I open the oil fill cap. I have vacuum tested both of the mounts, all the pipe work from the vacuum pump to the mounts and the pump itself (engine off) so I'm wondering if the leak is on something else the vacuum pump feeds?
does the vacuum system run anything other than the mounts and brake system? (mine is 2014 so the turbo system is not affected by vacuum)

5cilinder

Jan 18th, 2022 19:20

Quote:

Originally Posted by mr tickle (Post 2800712)

If you have a manual then there is a vacuum controlled egr cooler bypass...they almost all go bad.... the auto gearbox doesnt have one its for emissions with slightly higher temperature exhaust for the catalytic convertor.... you can blind them of and the bypass will be shut by a spring, which at operating temperature also always be if its working
Its located under the egr cooler

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