Rattling/growling noise

Tiny
BEN HUDSON
  • MEMBER
  • 2005 NISSAN ALTIMA
  • 2.5L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 152,271 MILES
This has been going on for almost a year now. I am just about all out of ideas. When my car is warmed up and been driving for twenty or more minutes, I start to hear a deep rattling/growling noise from under the hood kind of in the center. It only happens when warmed up, only when accelerating, its volume matches rpm and fluctuates at each gear shift. It does not happen when I am parked. If you let off the gas, it stops, but any gas and it starts up again. I have been told it is my exhaust heat shield, but I removed it and it still happens. Fingers crossed it is not my transmission. Here is a link to a video: https://www.dropbox.com/s/tz79ft06bempsfd/2017-02-06%2017.38.17.mp4?dl=0
Wednesday, February 15th, 2017 AT 5:45 PM

6 Replies

Tiny
STEVE W.
  • MECHANIC
  • 14,512 POSTS
Do you mean the screechy sound that sounds like chipmunks fighting? That sounds like timing chain wearing against the case. Probably a failing chain tensioner. Not something to put off.

Does it sound like this outside under the hood?
https://www.youtube.com/watch?v=S2TKYrem9uk
https://www.youtube.com/watch?v=S_4iMo5FUvc
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Wednesday, February 15th, 2017 AT 5:57 PM
Tiny
BEN HUDSON
  • MEMBER
  • 2 POSTS
It is possible. I had a new engine installed at 147xxx, however Nissan timing chains are plastic and are not known for their reliability. It is hard to describe. Here is an alternate link to the video I think my first one was broken. https://www.dropbox.com/s/tz79ft06bempsfd/2017-02-06%2017.38.17.mp4?dl=0
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Wednesday, February 15th, 2017 AT 6:13 PM
Tiny
STEVE W.
  • MECHANIC
  • 14,512 POSTS
I would try a simple check. Take a long screwdriver or other solid item, curl your finger over the top and put it tight against your ear, now with the engine running touch the other end to the timing chain cover.
like this-
https://www.youtube.com/watch?v=QvG9K95vFDY
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Wednesday, February 15th, 2017 AT 6:21 PM
Tiny
CARADIODOC
  • MECHANIC
  • 34,170 POSTS
There are two things to consider. Your engine uses a timing chain. If it is worn or the tension-er is not holding proper tension on it, the chain can rattle against the housing. An exhaust leak between the cylinder head and exhaust manifold can make a loud ticking sound that can sound like a rattle. That will only occur during acceleration or with a load on the engine.

There is a tool you might be able to borrow or rent from an auto parts store that borrows them called the "Chassis Ear". It is a set of six microphones, a switch box, and headphones. You clip the microphones to suspect points, then drive around while listening with the headphones. You can move the microphones around to zero in on the source of the noise. Be aware that many mechanics have never seen or even heard of this tool. Suspension and alignment mechanics use it to find rattles, squeaks, and other noises.
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Wednesday, February 15th, 2017 AT 7:13 PM
Tiny
CARADIODOC
  • MECHANIC
  • 34,170 POSTS
Sorry for butting in Steve. I went to dinner while thinking about this, then posted the reply without checking first for other replies.
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Wednesday, February 15th, 2017 AT 7:16 PM
Tiny
STEVE W.
  • MECHANIC
  • 14,512 POSTS
Not a problem DOC. More input is always a good thing.

I had my ears out the other day, hunting down a bad bearing on an Audi. It would only make a noise when turning right at "above average" speed.
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Wednesday, February 15th, 2017 AT 8:53 PM

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