[MATT13113]

My 2006 Acura MDX just starting making this rattling sort of noise on the belt side of the engine. Very intermittent of when it occurs mostly after the car starts to warm up you will hear it. Started out only occurring at idle but now can be heard more by fluctuating throttle. This may be unrelated but eversince this noise started the car has only been averaging 12.9mpg when it usually averages 15-16 and I only ever use 93 octane from shell stations. The car has 125,000miles. As of 2015 the timing belt, serpentine belt, water pump, tensioners, and alternator were all done. Any help would be greatly appreciated!!! Thx. Here are two videos of the noise...https://youtu.be/UTDjhYwIO9A
https://youtu.be/53k0RK3ASsE

 

[Bluepill]

1. Using a mechanic's stethoscope may help you pinpoint the noise source.

2. Removing the serp. belt will tell you if it is related to any of the components driven by the belt.

 

[tigre_perdido]

if i was you first check alternator bottom bolt if is lose ... sometimes when you touch alternator the threads of motor block where that bolt ties get damage. is being a problem on acura blocks and ends up breaking alternator top bracket

I had same problem on my 2002 mdx after changing an alternatora few weeks later ratling started and after 2 broken brackets i found my problem my block treads for alternator bottom bolt were damage i had to do an helicoil and i got a bracket from an acura tl that is more solid :wink:

 

[MATT13113]

Thx for the information. Will definitely be looking into those suggestions.

 

[Jim_2021]

My 2006 Acura MDX just starting making this rattling sort of noise on the belt side of the engine. Very intermittent of when it occurs mostly after the car starts to warm up you will hear it. Started out only occurring at idle but now can be heard more by fluctuating throttle. This may be unrelated but eversince this noise started the car has only been averaging 12.9mpg when it usually averages 15-16 and I only ever use 93 octane from shell stations. The car has 125,000miles. As of 2015 the timing belt, serpentine belt, water pump, tensioners, and alternator were all done. Any help would be greatly appreciated!!! Thx. Here are two videos of the noise...

I wonder you figured out what caused your engine rattling or not? My 2020 MDX started making same noise. Appreciate any thoughts! Thanks! -Jim

 

[pelletman]

Hard to tell from the video but I had a bad AC clutch that rattled like that. If you turn off the AC it goes away (I think). Stethoscope is very helpful in these situations

 

[Jim_2021]

Hard to tell from the video but I had a bad AC clutch that rattled like that. If you turn off the AC it goes away (I think). Stethoscope is very helpful in these situations

Thanks for the helpful info. In my case, even AC is off, the rattling still there. I have Stephoscope, tried several times from the top, haven't found yet. I will try again from the bottom before bringing to the dealer.