Strange rattling/fluttering noise when accelerating

[thecolonel]

My car seems to be running fine, but I'm getting a disturbing noise when I accelerate. It's hard to describe, but it's like an airy rattling(fluttering?) if that makes sense. It only happens from about 2000 to 3500rpms. I had a friend look at it and he thinks the turbo is bad. Does that sound right and if so what exactly will I need?

 

[Nc MSP]

mine is doing the same thing. it sounds like its coming from the left side of the motor by the cam gears?..... i dont think its the turbo. i think it might just be a vaccum leak or just a compression issue. let me know if you figure out what it is, ill do the same

 

[thecolonel]

figured it out

as it turns out the guy who looked at my car isn't the most reliable mechanic(imagine that!!). the bolts connecting the intake manifold to the turbo have come loose and are causing the rattle and exhaust leak. i would check that if you are having the same problem. thanks for the response!!

 

[Nc MSP]

dude if that is the problem i will drive to texas and take you out to dinner....and you mean the exhaust mani to turbo or the intake mani to head?

 

[thecolonel]

On mine it was two of the four(i think) bolts where the turbo connects to the manifold. Right there where the O2 sensor is under the heat shield. Check it out and let me know.

 

[StealthWyvern]

On mine it was two of the four(i think) bolts where the turbo connects to the manifold. Right there where the O2 sensor is under the heat shield. Check it out and let me know.

So your exhaust to manifold bolts... If thats the case thsi will cause a huge exhaust leak as well... im surprised it didnt soudn like crap on first start up in the mornings as well

 

[Jo060]

I get a weird hoot noise around the same RPM. Almost sounds like a fart or...someone running their finger across a filled balloon. After doing research it may be the BPV, i guess they also call them "hooter valves".

 

[YlwMSP]

Was it kind of a sputtering sound when you accelerated a little harder than normal? Because mine makes a weird sound like that and it kinda sounds like an exhaust leak is starting (which may be a good justification to buy an exhaust)

 

[patricktrefry]

Well, its been some years since this thread was started... Hope someones still around. I am experiencing the same issue, however mine sounds like a chunk of metal is being chewed up by the garbage disposal. I am currently dealing with shot susp., bad front pass wheel bearing and rotors/pads which are all being taken care of this weekend. I have attempted to check the ecu to spy on sensor data that might not be up to par, unfortunately my torque app is no longer able to make a connection to the ecu - not sure if this is a new issue or just a software glitch with the app. Overall the engines performance sounds and seems to run smoothly. I will check the mani bolts to ensure they are secure... has anyone else got any suggestions?

 

[hornsfan10609]

The sound you describe is not a good one, that is for sure. I worked as a Mazda tech for a couple years and the turbo CX7s were among the worst cars they ever built. If properly maintained they will be fine but most people didn't. The VVT may be failing, that's usually the rattling sound the motor makes. I would take it to a dealer, even on the service drive they will be able to tell you immediately if it's the VVT or not. Mazda extended the warranty on them but if it has over ~100k miles I believe it won't be covered.