A friend of mine in NC has a 2005 XC70 with around 95K miles. While the engine is cold, any accelleration produces a very high pitched whine that increases with speed. It does not do it if I let up on the throttle, only when giving it gas. In any gear.

As the engine warms up the whine decreases in intensity until after about 10 mintutes of driving. Then all is normal.

I check the tranny fluid, clean and full and recently changed.

As we were both on vacation, we did not get under the car in the Hotel parking lot. I told him to check the bevel gear, and flush it.

ANY comments or other possible solutions are welcome!

Thank you,

On the lighter side of thought, intake or turbo loose,tightening up as it gets hot,?

I wonder if it could be the air pump. I was about to post a similar question about a high-pitched whine when the engine is cold. It lasts about a minute (it does not get louder with acceleration, though), and then generally stops. Sometimes it will do it again at idle (stoplights, traffic, etc.)

I am not sure if the 2005 even has an air pump. Regardless, it is not an electrical motor as the whine increases with vehicle speed and makes no change when shifting up to another gear.

Matthews volvo site suggested that the exhaust is touching the prop shaft while the exhaust is cold.

I'd say turbo related, even if it is not burning oil and runs like a top. I say this based on the 98 XC I bought, purchased short cash with about 192k on it (crazy you'd say?)....but in all seriousness I had the same issue and symptom with that car and drove for 30k miles with absolutely no degradation of engine performance.

My 07 has started to develop this noise oh so slightly, and she just hit 108k. After getting to operating temp its non existent and I've used Mobil 1 since purchase a few years ago.

I do believe reading up on an issue where the turbo, or some element of the exhaust in close proximity to the turbo suffered some expansion and contraction issues after a period of time, no harm if left unattended to though. I would double check the rubber gasket/hose that connects the boost pressure pipe to the turbo itself, check for looseness and cracks, may require an remove and inspect to makes 100% sure. Remember, this car, although a LPT still boosts up to about 8PSI at minimal RPM, even a small knick may cause such a sound.

General turbo test though, pull fresh air inlet house of any give a wobble to the turbine assay, inspect for abnormal movement. While there may be a great time to pull the PTC orifice assy and clean.

Good Luck.
Steve

My wifes car is a 04 xc70 with 135,000 miles on it, we had a whine that first sounded like the tires,rotated them and it got worst,after afew weeks it got to the point where the whine changed, when you gave it the gas and coasting, I changed the right front cv axle, the axle was dry and tinny sounding and the bearing was hard to turn,took it for a ride and the whine changed, took it back to my shop and looked under the car and found the drive shaft would move about a quarter of an inch, the bevel gear pinion bearing was gone,replaced the bevel gear and when I was putting the drive shaft back in the front cv on the driveshaft fell apart and a ball bearing fell out, ordered a new cv from colordo driveshaft and got back in ,now the car runs like new,, that was the short story.

bum turbo ?

Thanks, but I tried that. The turbo is good and the car really does run nicely. The engine burns oil, but I didn't have time to go through the PCV system with him. I will send him a follow up Email soon.

BTW, I found a right hand mirror for Xena. No, not that kind! This is for mounting on the fender while towing a trailer. I will bring it by some time.

This is likely to be your alternator regulator pack. They can whine intermittenly.
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Tek

Thanks Tec,

But the whine only happens when in gear and moving. I tried revving the engine in N and nothing happened. Once the car heats up the whine goes away.

Needless to say, this is a LOUD whine, like a jet engine, but gets softer and softer after a few minutes. 10 minutes into the drive and the noise was gone.

I emailed my friend last week and it is still happening. Another poster indicated it is happening to his friends car (2004) in Michigan. Mileage unknown. But he also had the ATF flushed.

I had this same problem. The whine would go away for me when making a hard left turn. The problem was cured when I replaced the front right driveshaft.
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1959 Volvo Amazon 121, 1998 Volvo V70R AWD