Rattling, Light Acceleration, A/C ON

[Rollout-G]

Hi everyone,

I've searched and found similar circumstances, but not completely the same; maybe someone can shed some light on my problem.

I have a 2006 Mz3, 2.0 Automatic, 141,000kms, and up until this point, running like a charm.

Starting in early May, I noticed that when the A/C is on, a metalic rattle or grinding sound occurs from the engine on the passenger side when pressing on the gas lightly. Other observations:

- It occurs only at lower speeds (haven't heard it above 40km/h), and usually if the car has been running for a few minutes (it will right on startup).
- It happens only when the car is engaged in D (nothing when pressing gas in Neutral).
- It happens only for a second or two, and doesn't stay for the entire time I hold down the gas.
- It does not happen when the car is in stop, as I have read from some others.
- Lately I have been hearing it under the same circumstances, even after I have turned the A/C off, though the volume is much lower.

I'm hoping it's not the A/C compressor because I know it's a pricey affair, and with my type of mileage, is not worth it at all. The A/C has however, been working no problemo.

Anything would be appreciated!
Thanks!

[TheMAN]

check the motor mount if its broken

[Zotaga]

I doubt it's the A/C. If you have a torque wrench then go tighten the mounts, and check your belt. If there is a lot of slack in it, then that could be your issue. I know I've posted a lot about the belts on here, but it seems like that is the answer to a lot of these problems. A loose belt due to wear, or a bad tensioner, could cause a slight rattle.

[Rollout-G]

Thanks Zotaga - got it checked out this morning and indeed, it's the tensioner.