Unusual Noise when Accelerating
 

Hey guys, a few days ago I started hearing a different noise from the engine when accelerating the car. The car seems to run fine, but this noise is different from the noise the car makes when revving up. I'm beginning to suspect it could be the serpentine belt, or the timing belt. Anyone have any ideas or suggestions? Thanks.

Is it like a rumble noise?

I don't think it'd be the serpentine belt if you're accelerating since it runs through all the electrical components.

Not really, it sounds like the regular engine, but with like a higher pitch most noticeable up to about 2500 rpm. Its hard to describe, but when I park the car after a drive I let it sit idle for a moment or two, and I hear what sounds almost like oscillations. The car has not thrown any check engine codes on me yet, but I'm worried by the it does (if it does) it'll be right before something happens.

Does the check engine light work?
Are all the engine mounts good?

Could it be related to the turbo?

The check engine light does work, but no lights are currently on, so either its just a fluke, or the system doesn't recognize it. I haven't done or moved anything in the engine, so everything should be fine and in place.

I certainly hope its not the turbo though, sounds expensive to repair (like everything else unfortunately).

The only thing that has been done to the car is a replacement of the mass air flow sensor after it failed. That was almost 3 weeks ago though, and it worked fine after that.

I would check all the engine mounts really good.

I'm going to try and see my mechanic tomorrow so he can check it out. If he doesn't find anything, maybe I'll have to take it to the dealership. I'll let you know what happens tomorrow.

UPDATE:

Well, I went to my mechanic today, after driving about 100 miles to and from school. He opened up the cam shaft cover, and we were able to determine that the noise was coming from one of the components of the timing belt, most likely the tensioner. Tech (and those that are wiser than me), do you think this was a possibility? Either way, I'm heading back tomorrow morning and having the entire thing replaced (timing belt, water pump, idler pulley, etc.) Since I bought the car used, and with no service records, I figured that was the safest way to go. I'll update this again when its finished.

I know I'm not counted as a "wiser one", but I will say that it's a good choice to go ahead and have them replace everything. I changed out the timing/serpentine belts and water pump when I got my S70. My dad and I looked at the belts after we got them off and they were in an ok-ish condition and would probably last a couple more years, but it's pretty much always a good idea to replace them.

Yes I would say is if very possible.

2ND UPDATE:

Well, I got the car back today after my mechanic was sent the wrong tensioner yesterday. Turns out the tensioner had gone bad (which I'm told is something that doesn't happen too often) after it became very difficult to spin the moving part. That was wearing out the metallic surface of the tensioner itself as well as the belt itself. So, the entire timing belt kit was replaced at the cost of $500 (Volvo wanted $575 just for the timing belt, all other parts were extra). Nevertheless, this took care of the problem and its running great again.

Lesson learned: if you hear an unusual noise, get it checked out as fast as possible. My mechanic told me it was good that I brought it in, because if I would have waited, it could have snapped soon.

Thanks for your input guys, it really helped out. Hope this helps others.

Glad all is well now!!

hi I just started to get a noise from the engine bay only between 4000-6000 rpm in brisk accelerating conditions. it sounds like a engine with a after market cat back exhaust, and it does not happen when speeding normally. Only when you really put the foot down or overtaking with more throttle. It happens also when stationary with the gear in P or N, but only between 4000-6000 rpm. I had a change of timing belt, serpentine belt . engine mounts etc replaced. And I have no CEL. Really weird...did yours do the same thing?

That sounds strange to me. I actually don't think my car has made it past 4000 rpm. Not to say that it can't, but I guess I just haven't pushed it that much, I'd prefer not to. My car only made a bizarre noise during low rpm of around 2000 or so. Since I have no experience with it myself, I can't really say if it is a normal noise or not. Perhaps Tech can shed some light on this?

It could be many things.

I got the same problem with my s40 t5 2007. Did u get the problem fixed?what was it?
 

:(:confused:
Chanced water pump and everything you did . And still have the same whistling nois whem revving up

Check to make sure all the hoses from the turbo to the intake are secure and there are no small holes in them. You could be hearing a small pressure leak. Usually a whistling noise on acceleration is the turbocharger spinning up, or a pressure leak. A squealing noise is usually a belt or metal to metal contact. and a sucking gurgling sound tends to be a vacuum leak. Hope that helps.