2006 Mazda5 intermittent rattling noise in engine

[korey99]

Hello all-

I'm trying to figure out the source of this intermittent engine noise. It's a 2006 Mazda 5 with the 2.3L, coming up on 90k miles.

http://youtu.be/6Xevw74pTRQ

I can't determine by location what's causing the noise. It is most noticeable at idle. When I remove the main belt, it still occurs (so it's not the alternator, idler pulley, or water pump). I have not removed the AC belt yet because it's a stretch belt.

Does anyone recognize this issue? Timing chain? Harmonic balancer? Engine mounts? AC compressor?

Thanks,
Korey

 

[njaremka]

heat shield?

 

[mazdadude]

My first guess is the A/C compressor... LOL ... It sounds nasty!

 

[Davebert]

It sounds like the problem I had when the AC clutch was bad. It was not a constant knocking noise and it took a few visits to the shop for them to locate the source of the noise. The mechanic use a long screwdriver and place it to different part of the car and put his ear to the handle to find the source of the knocking which turned out to be a bad AC clutch.

 

[korey99]

It sounds like the problem I had when the AC clutch was bad. It was not a constant knocking noise and it took a few visits to the shop for them to locate the source of the noise. The mechanic use a long screwdriver and place it to different part of the car and put his ear to the handle to find the source of the knocking which turned out to be a bad AC clutch.

Davebert-

That's my leading theory so far. I'll test it out with the fake stethoscope trick soon. Did yours make this sound when the AC was off?

 

[Davebert]

Had the knocking sound with the AC on or off.