Hello,
I have a 2009 Volvo S40 with 84,000 miles it was driving good when I purchased the car, recently the car vibrates while driving when I accelerate, when it’s in park and while in neutral when I give it gas. The vibration seems to be coming from the engine. I had my mechanic look at it a couple weeks ago and ended up having the lower control arms and axels changed out and the vibration is still the same.
Does anyone have an idea what this might be?
I appreciate any feedback.

 

Motor mounts / transmission mounts are my first guess (but only that). Have someone you trust cycle the shifter through P-R-N-D-N-R-P and see if you can see unusual movement anywhere, or if you see an obviously bad (torn) motor mount. The key (that should have clued your mechanic in on the fact the problem wasn't axles and LCAs) is that it happens in park and neutral (where the LCAs and axles aren't doing a thing).

 

Yes the engine mounts dont last for ever ,we changed ours after 80k (kilometers) and around 10 years , which is ok I suppose

 

I’ve recently changed the motor mounts and the axles on my 2009 S40 and the vibration issue is still the same.
It’s doing it when the car is in park around 20,000 rpm and when it’s in drive starting between 45-55mph, the vibration is coming from the engine.
Anyone have an idea what I need to do or look for?
I really appreciate any insight that can help.

 

hopefully you meant 2,000 RPM :-) Is this a turbo or NA engine? Thinking aloud, if you have vibrations when the car is in neutral or park, then you can focus on engine components and rule out suspension and axles. Did you follow Habby's advise and watch the engine for any odd movements? If you can have somebody rev the engine, you may see or hear something. I assume you don't have a CEL light or stored codes indicating a possible misfire. You didn't mention what kind of vibration - ie a buzz vs a moan? My check list would include exhaust/turbo, transmission mounts, accessories/brackets (PS pump, AC compressor, alternator) and how the drive belt looks. Next I'd pop off the timing belt cover to see if you see anything odd with the cam gears, water pump area etc. You may even consider removing the serpentine belt and starting the car up and giving it a rev to see if anything changes. Also, check the bolts to the motor mounts just to make sure they were properly torqued when the parts were replaced.

 

Yeah, meant 2,000 😅 typo. It’s not a turbo engine.
It’s hard to explain the vibration of the car. (The A/C compressor is bad, maybe that’s one of the reasons.) I’ll go down the list with my mechanic and keep you posted on the updates. Thank you

 

Got the axels, motor mounts, a/c compressor changed and still vibrating at 1,000rpm or 4,000 rpm when you accelerate the car. The vibration comes from the engine when you step on the gas. The car was scanned again, no codes. I don’t know what else to check at this point.
Any help is appreciated.

 

So you've done:
Lower control arms (a very likely suspect, as worn bushings will do that)
Engine mounts (I wonder if they got all of them...)
Axles (also a likely suspect, though more speed-related than engine RPM-related)
A/C compressor (could be... but wouldn't be high on my suspect list)

"Vibration" can mean a lot of things - is it mainly making an annoying noise (metallic or "dull")? Or is it more of a vibration you feel through the steering wheel (or seat or ???)?

There are also mount(s) on the transmission crossmember that could be a problem.

Does the vibration seem to be related more to engine torque (happens at high throttle, but maybe not at low throttle), or is it entirely RPM-related (happens at 4,000 rpm no matter how much throttle)?

 

Yes, it’s RPM and engine related it does it at 1000 rpm and when you put more gas it does it at 4000 rpm. Between 1000-4000 you don’t feel it as much, but when you go higher you feel it. You feel the vibration throughout the car in the seat and the steering wheel. Seems to be coming from the engine.

 

Engine vibration is managed by the engine mounts on all motors up to a point , as you have changed them hopefully well ,then its an engine issue