'08 Volvo V70 - Very loud high-pitched whine

lumpyboris · Post by **lumpyboris** » 05 Aug 2018, 09:43

On a road trip, and had (non-turbo) car checked out day before I left -- everything was in good order, except for a couple random misfire codes that didn't seem too troubling so we left them.
Within the last 100 miles or so of my trip, the car started making this very loud high-pitched whine, which sounded like it was coming from the driver's side of the car. The sound was continuous when idling, parked, coasting, or slowing down; the sound went away when I was actively giving the car gas. The whine was not connected to AC/radio/anything like that. The whine was not connected to braking/the brakes. Nothing else about the engine sounds off, the car feels like it is running smoothly and normally. After driving for about 95 out of the 100 miles, the "check engine" light came on. Any ideas?

Post by **Rattnalle** » 05 Aug 2018, 10:43

Constant pitch and volume or does it change with engine revs?

lumpyboris · Post by **lumpyboris** » 05 Aug 2018, 11:19

Hi Rattnalle,

Constant pitch and volume. Like the tone you hear in your ears after going to a loud concert or something.

Post by **Rattnalle** » 05 Aug 2018, 11:27

Interesting. That would seem to rule out both vacuum lines and anything connected to the engine.

If the sound is there at idle you should probably try pinpointing it a bit more.

Georgeandkira · Post by **Georgeandkira** » 05 Aug 2018, 11:33

Have you had the code read? Do you have a reader.

Does the '08 have a motor driven air pump to "fan the fire" in the cat so it warms up faster?
It's supposed to turn off after a while but could be broken.

Does the fuel system have a valve to return fuel to the tank?

Have you lifted the hood and tried to zero in on it? Get a tube to focus your hearing.

Post by **oragex** » 05 Aug 2018, 12:12

lumpyboris wrote: ↑05 Aug 2018, 09:43 the sound went away when I was actively giving the car gas

How many miles on this puppy? I would bet a few $ on the PCV box, if the noise goes away as you pull the dipstick or undo a little the engine oil cap. If that seems to be the issue, I would drive the car unless removing the dipstick, or some engine seals may blow out (by the way, also check the engine oil level). Other things to do is to listen near the serpentine belt pulleys (with great care because of the rotating parts). As mentioned above may use a tube to listen www.youtube.com/watch?v=qVWY2fMzrpc

Also see if the noise stops when depressing the gas pedal

By the way, wasn't aware Volvo had the non turbo up to 2008 (or even 2009 perhaps?)

Post by **RickHaleParker** » 05 Aug 2018, 14:44

Did you check the power steering fluid level?

lumpyboris · Post by **lumpyboris** » 05 Aug 2018, 16:07

Yes, all fluids are good!

She's at just under 170 miles

thank you for all the suggestions! I will take it to my mechanic and toss these ideas around

Post by **oragex** » 05 Aug 2018, 17:22

Only thing, maybe if you get an estimate don't hesitate to update this, we may share suggestions about which part brands/fluids are better to use

Post by **chrism** » 05 Aug 2018, 20:25

Does the whine stop if you loosen the oil filler cap?