2003 V70mbase Recognize this sound? 31400693 Topic is solved

Post by **Biggertuna** » 17 Dec 2020, 15:58

My '03 V70 Base (~180K mikes) is making an odd noise after I turn it off. The noise starts off quite loud, decreases a bit, then continues for 2-3 minutes until it's gone. I've never heard it before and it appears to be coming from underneath the air filter. See link to video below.

Any guesses or ideas of the cause? Thanks for the help!

Video
https://www.dropbox.com/s/wjy7a2jgkcwxu76/V70Noise.mp4

Post by **oragex** » 17 Dec 2020, 18:46

Sounds like a tired vacuum pump. You may have a vacuum leak somewhere, one place to start is the 'switch' right in the center of the video with brown connector. On the switch, it says 'motor' on one side, make sure it's the hose that goes down towards the pump. If that's fine, may try replacing the switch if the cap looks broken - but no guarantee it will quiet the pump. My pump was buzzing because the brake pedal seal to the brake booster was leaking - may search on youtube

Post by **Biggertuna** » 17 Dec 2020, 19:35

Checked the 'switch' and upon touch, the cap sprung off so I'll have to replace it. Otherwise, the hoses look ok and are connected in the proper order.
Thanks for the tip. Let's see what happens after I replace the switch.

Post by **abscate** » 18 Dec 2020, 03:10

That’s it. If you put a zip tie around the switch before it springs apart you save yourself switchreplacemrnt.

The new one is improved design, I believe, but a zip tie on a junkyard one or used replacement

Post by **E Showell** » 18 Dec 2020, 15:06

Although a switch, I have referred to this as the "jack-in-the-box valve" in the past. Now you know why.

Post by **Biggertuna** » 21 Dec 2020, 13:02

Swapped out the old switch today with a Volvo replacement (couldn't find OE/OEM/Aftermarket). Noise is gone and brakes aren't as spongey either.
Replacement switch appears to be of better quality as well. Don't think I'll be experiencing the "jack-in-the-box" effect again.
Thanks for the help.

Post by **abscate** » 21 Dec 2020, 13:10

Added model and part number to thread title

The new part is improved design from OEM

https://www.fcpeuro.com/products/volvo- ... o-31400693

Post by **Biggertuna** » 21 Dec 2020, 13:57

I ordered this one. I think it's the same part, but different OE numbers.
https://www.fcpeuro.com/products/volvo- ... o-31265825