Buzzing noise on deceleration only if A/C is OFF.

JCANTERGIANI

MEMBER
2001 MAZDA MPV
2.5L
V6
2WD
AUTOMATIC
112,000 MILES

2001 Mazda MPV 2.5 V6 automatic with 112K miles. When parked, I notice the engine makes a buzzing noise on deceleration only if the A/C is off. So, if I rev it up and then let it go down, it buzzes for a few seconds. If the A/C is turned on and is cycling, the noise doesn't happen. If the A/C cycles off, the noise comes back on deceleration only. The buzzing noise does not sound like it's coming from the compressor, rather near the top front of the engine in the general area of the timing belt cover.

Thank you for any ideas you may offer.

5 Replies

HMAC300

MECHANIC
48,601 POSTS

Check to see if belt hits cover then check belt and tensioner for wear recommended replacement of belt and tensioner is 60,000 unless in California where it is 90,000

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Thursday, January 14th, 2016 AT 12:06 PM

JCANTERGIANI

MEMBER
11 POSTS

Thanks for responding. I just realized that this Mazda MPV 2.5 V6 has a timing chain (not a belt), unlike the Mazda 626 2.5 V6 which has a belt. The buzzing noise sounds like it's from the general area of that top sprocket area, which I think is power steering, Here is a YouTube video of someone's MPV which has the exact same noise on deceleration. Do you think the power steering pump can make this noise when the A/C is off and not make the noise when the A/C is on?