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Growling Sound on Acceleration

8K views 12 replies 9 participants last post by  dana.kennington 
#1 ·
Was driving my Sister's 2010 XC90 with 110k miles the other day. It drives fine but noticed that that when cruising along between 30mph to 60mph and I press the gas to accelerate there is a growling sound coming from the front. Can't tell whether its from engine or drive train. According to them its been that way since they got the car at around 30k miles. The dealer supposedly told them thats the characteristic of the 3.2. Any thoughts.
 
#2 ·
Check the front muffler, flex pipes and the upper torque mount. The torque mount when goes bad allows the engine to “tip” uncharacteristically which puts more flex on the flex pipes. The front mufflers crack and the leak at that spot sounds and feels like metal on metal,through the floor but also gives a growl, moan sound.
 
#3 ·
Most common "growling" on acceleration I have seen is the Upper Torque Mount part number 30680708. Its on the passenger side, top of engine. The rubber bushing shrinks and just rattles. You can grab the aluminum mount and shake it, if it moves, it should probably be replaced. Lower hydraulic engine mounts can also cause this type of noise when they collapse.
Here is a photo of a bad one.
 
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#5 ·
For what it is worth, the 3.2 is known to be a bit of a noisy - growly engine. What you are hearing may just be its natural disposition. A torque rod mount failing at 30K would be highly unusual. Not out of the realm of possibility - just unusual.
 
#6 ·
I just took ours out for a look and definitely at the forward end it was quite loose. To me it looks as if it could be an age related thing whereby the rubber has just shrunk. I pumped some silicone all around the voids and we'll see how that goes. There is one in the Amazon cart if it does not work out.
 
#7 ·
Could you define "growling?"

As others have already said, if there is a vibrating like sound or feel, then it could be related to the engine mounts/torque rod. If it is a smoother vibration growl more so heard not felt, then it could be the transmission, such as a shudder.

If it is an air growl like someone installed an intake on a Honda Civic Si, then that could be the normal variable length intake "growling" when the intake flap changes to adjust for the acceleration in higher rpms. Like a VTEC in Hondas, the 3.2 also has cam profile switching, or second cam, it switches to in higher loads and rpms.
 
#9 ·
The noise is only another symptom. Because the bushing shrinks, there is excessive movement every time there is acceleration and deceleration, the engine rock more violently. It eventually will destroy the hydraulic engine mounts that are MUCH more expensive. So just because you don't hear it, its still bad.

Other issues on these engines that can "growl". I only listed what I see the most in my first response just by what OP said. Also could be Sister uses cheap gas and you are hearing pre-ignition/detonation. Premium fuel is recommended, see the owners manual.
Failing AC Compressors AC/Clutch
Failing Belt Tensioner
Failing Idler Pulley
Failing one way clutch on REED unit
Failing bearing in REED unit
Failing one way clutch on alternator.
Failing bearings in Alt.
Low power steering fluid
Failing water pump
Failed hydraulic engine mounts
Failed Strut mounts (although usually heard driving over rough road or bumps but you would be surprised how far some people let things go)
Low Transmission Fluid/Bad Trans
Low Oil
Failed PCV Diaphragm (has more a high pitch squeal and may have misfires and a CEL)
Those are just a couple of noise issues I see day to day.

Can this apply to a 2017? someone asked, absolutely but the noise on those are more of a rattle on start-up and clunking when shifting gears from park to reverse or drive. Its a different part than the one I pictured but serves the same purpose. Not fixing it ruins the hydraulic mount underneath it fairly quickly. You'll know when the black hydraulic leaks out everywhere.
 
#11 ·
Because of the easy way in which my wife drives the car I doubt that our engine mount has ever come close to the end of its travel in the torque mount slot. The silicone 'fix' has taken the rattling noise away. Next time I would try using a couple of pieces of tongue depressor and silicone them in on either end of the loose rubber piece.
 
#12 ·
Reviving this old thread to share some info as I replaced this part today (upper torque mount 30680708) on my 2010 XC90 and the difference is amazing. Just like
Oceans60R said, I used to have the growling / rattling noise when in gear or accelerating when the vehicle was cold and the noise would dampen a bit when warm. I also had an occasional jerk on acceleration like it would hesitate or slip at times. Since i put the new one part on no noises, hesitations or jerking happening. I amazed at how quiet the car is now and how smooth the acceleration feels and wish i would have replaced this part sooner. Took only 20 min and most of that time was to find some penetrating oil in the garage as the bolt near the front of the car wasn't budging. I didn't have to remove the cover just the two mounting bolts that hold the part in place and was able to slip the new torque mount back in from under the cover. I highly recommend replacing this part if it hasn't been done already and part was only $66 in total from FCP.
 
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