I just picked up a 2009 S40 2.4i and realized a slight 'kick start' from the engine bay whenever I put it into D and accelerate within 3-5mph. The sound is similar to when the Air conditioning kicks in on an older car; kind of a slight crank or a fan clutch type of noise. It would only do this once when I start the ignition and put in D to drive. Everything is fine so long as I do not shut down and start the car again.

I popped the hood with the engine running and can hear/feel the fan blowing. I then shut the car off and re-started it, went back to listen and I believe this time the fan didn't go on (because it wasn't in Drive)....then I put it in gear and drive it slightly until that 'crank' comes back...went and open the hood again and I'm pretty sure this time the fan was blowing.

Anyone experience this before? Can it be the fan clutch or alternator bushing? I don't know what the hell I'm talking about but common sense tells me that these noise are pretty synonymous with the said parts. Any feedback would be appreciated.

Thanks!

 

...Bump...anyone? What can be the culprit?

 

Could it be the a/c compressor kicking on along with the radiator/condenser fan? Do you have the climate control set to AUTO?

 

No, I made sure none of those were on. I thought it was the fan but when I had someone else (not mechanic) looked at it stopped and didn't make any sound. This only happens when I turn off the ignition and start the car, put in drive, accelerate...then crrrraaannnng like some kind of pulley or something kick-started. I also felt it through my pedal. I can be driving all day and the car would be fine - so long as I don't park and come back. So this will happen every morning when I go to work. It is really annoying.

 

So I took the car in to my local Volvo dealer and sat with the tech while we took it for a drive; his first words were "this is normal". Apparently the ABS self-diagnose (or self-cycle) itself every time when the ignition starts. He said Volvo started this since 2001 and he was 1,000,000% sure of it.
I started googling the terms since I now know what they are and sure enough quite a few folks were concerned and got the same answers. I also found out from other discussion forums that Volvo did acknowledged this on page 151 of the owner's manual under ABS Brakes, it states:

"The system performs a self-diagnostic test when the engine is started and when the vehicle first reaches a speed of approximately 12mph (20km/h). The brake pedal pulsate several times and a sound may be audible from the ABS control module. This is normal"

What a relief!!!