This one is new

Anubisxc70 · May 20th, 2018, 21:47

2004 XC70 D5 awd.

Hello today this happen.
I have the poping noise , i guess like most of us when you open the oil cap.
My vacuum pump is working and my engine mounts are new and working fine. But the poping noise still goes, not loud but its there.

I went to the vacuum pump and pull the brake hose....guess.....it stoped no poping sound??????!!!!!

Anybody?????!!!!

aland · May 21st, 2018, 10:11

Simon (CheshireD5) is the expert here on popping noises on the D5. Have you seen his video here? https://www.youtube.com/watch?v=QHLyubTrIQ8

I'd suggest you confirm that when you remove the small pipe from the vacuum pump and hold your finger over it that the noise remains or goes.
- If it goes, this suggests you are losing vacuum somewhere other than engine mounts, maybe pipes, VNT solenoid or possibly the VNT actuator.
- If it remains, maybe you have a leak on the brake servo side - maybe clamp off the hose before the one-way valve then after to work out where it's leaking.

My car seems to have a slow leak in the brake servo, but not enough to cause any issues.

aland · May 21st, 2018, 10:19

Quote:

Originally Posted by Anubisxc70

2004 XC70 D5 awd.
I went to the vacuum pump and pull the brake hose....guess.....it stoped no poping sound??????!!!!!

Just re-read your post. Did you mean that with the brake vacuum hose removed you have NO noise? That would mean that with no vacuum load the noise stops - IIRC mine is the same (but it's been a while since I tried that!)

Anubisxc70 · May 21st, 2018, 14:14

YEs. if i remove the brake hose without covering any holes the sound stops.

MarvinMitt · May 22nd, 2018, 10:20

As far as I have read and learnt, this appears to be normal behaviour.
The explanation that I have (which should be taken with a grain of salt) is that the vacuum pump only pops loudly when there is a mild vacuum in the system and air has smoewhat restricted passage. If there is a strong vacuum and no air passage (vacuum on one side and atmospheric pressure on other) or no vacuum (close to atmospheric pressures both sides of the pump) then it doesn't produce that strong popping sound.

Anubisxc70 · May 22nd, 2018, 20:59

So the hose that goes out of the vacuum pump to braking system. Where it connects? When can i see a diagram? What might be causing that pop noise.....how natural is it? Does it make it when its a new car or its something that can be fixed or replaced? Is it a part that gets warned?

MarvinMitt · May 23rd, 2018, 11:50

The popping sound is the air the vacuum pup that sits on the right end of exhaust camshaft pulls under the valve cover. It has two vacuum outputs (air inputs) - bigger for brake booster and smaller for engine pad valve and if Euro 3 engine, the turbo governor. Search around this forum, there's a lot of information and speculation on these threads from last year I think.

Anubisxc70 · May 23rd, 2018, 17:06

So all this to .....search the forums???!!!

OK,.....

MarvinMitt · May 23rd, 2018, 22:32

Sorry, but if you ask "the hose that goes out of the vacuum pump to braking system. Where it connects? when can i see a diagram?" then it seems that you don't know the basics of how the brake booster and vacuum system works and from these grounds it takes too much of an effort to explain it in every thread separately. Look up for a video on youtube, search the forums. If your knowledge is bigger than that then ask more detailed questions and people shall answer if they can.

May 20th, 2018, 21:47	#1
Anubisxc70 Master Member Last Online: Sep 25th, 2021 23:16 Join Date: Aug 2017 Location: Sturminster Newton	This one is new 2004 XC70 D5 awd. Hello today this happen. I have the poping noise , i guess like most of us when you open the oil cap. My vacuum pump is working and my engine mounts are new and working fine. But the poping noise still goes, not loud but its there. I went to the vacuum pump and pull the brake hose....guess.....it stoped no poping sound??????!!!!! Anybody?????!!!!

May 21st, 2018, 10:11	#2
aland Senior Member Last Online: Jan 17th, 2024 15:41 Join Date: Dec 2004 Location: Luton	Simon (CheshireD5) is the expert here on popping noises on the D5. Have you seen his video here? https://www.youtube.com/watch?v=QHLyubTrIQ8 I'd suggest you confirm that when you remove the small pipe from the vacuum pump and hold your finger over it that the noise remains or goes. - If it goes, this suggests you are losing vacuum somewhere other than engine mounts, maybe pipes, VNT solenoid or possibly the VNT actuator. - If it remains, maybe you have a leak on the brake servo side - maybe clamp off the hose before the one-way valve then after to work out where it's leaking. My car seems to have a slow leak in the brake servo, but not enough to cause any issues. __________________ 2004 V70R 2008 XC90 D5. 2011 C30 2.0 Past: V70 D5, 855 T5, 940, V40 T4, S40

May 22nd, 2018, 10:20	#5
MarvinMitt Senior Member Last Online: Nov 1st, 2021 21:18 Join Date: Sep 2016 Location: Tartu	As far as I have read and learnt, this appears to be normal behaviour. The explanation that I have (which should be taken with a grain of salt) is that the vacuum pump only pops loudly when there is a mild vacuum in the system and air has smoewhat restricted passage. If there is a strong vacuum and no air passage (vacuum on one side and atmospheric pressure on other) or no vacuum (close to atmospheric pressures both sides of the pump) then it doesn't produce that strong popping sound. __________________ 2002 V70 D5

May 22nd, 2018, 20:59	#6
Anubisxc70 Master Member Last Online: Sep 25th, 2021 23:16 Join Date: Aug 2017 Location: Sturminster Newton	So the hose that goes out of the vacuum pump to braking system. Where it connects? When can i see a diagram? What might be causing that pop noise.....how natural is it? Does it make it when its a new car or its something that can be fixed or replaced? Is it a part that gets warned? Last edited by Anubisxc70; May 22nd, 2018 at 21:03.

May 23rd, 2018, 11:50	#7
MarvinMitt Senior Member Last Online: Nov 1st, 2021 21:18 Join Date: Sep 2016 Location: Tartu	The popping sound is the air the vacuum pup that sits on the right end of exhaust camshaft pulls under the valve cover. It has two vacuum outputs (air inputs) - bigger for brake booster and smaller for engine pad valve and if Euro 3 engine, the turbo governor. Search around this forum, there's a lot of information and speculation on these threads from last year I think. __________________ 2002 V70 D5

May 21st, 2018, 14:14	#4
Anubisxc70 Master Member Last Online: Sep 25th, 2021 23:16 Join Date: Aug 2017 Location: Sturminster Newton	YEs. if i remove the brake hose without covering any holes the sound stops.

May 23rd, 2018, 17:06	#8
Anubisxc70 Master Member Last Online: Sep 25th, 2021 23:16 Join Date: Aug 2017 Location: Sturminster Newton	So all this to .....search the forums???!!! OK,.....

May 23rd, 2018, 22:32	#9
MarvinMitt Senior Member Last Online: Nov 1st, 2021 21:18 Join Date: Sep 2016 Location: Tartu	Sorry, but if you ask "the hose that goes out of the vacuum pump to braking system. Where it connects? when can i see a diagram?" then it seems that you don't know the basics of how the brake booster and vacuum system works and from these grounds it takes too much of an effort to explain it in every thread separately. Look up for a video on youtube, search the forums. If your knowledge is bigger than that then ask more detailed questions and people shall answer if they can. __________________ 2002 V70 D5

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