2004 Dodge Durango Unusual noise (like a lawnmower) when en

Tiny
GEOVERJAM
  • MEMBER
  • 2004 DODGE DURANGO
  • V8
  • 4WD
  • AUTOMATIC
  • 78,300 MILES
I have a 4.7L engine in my 2004 Durango and since 6 mos ago, I noticed an unusual noise like the sound of a lawnmower from the right side of the engine when the engine is cold. Some said it might be a leaky exhaust system. I also noticed my mpg dropped from 15.6 to 13.6 mpg. I've replaced tires, spark plugs, oil, oil filter and air filter.
Saturday, March 6th, 2010 AT 1:23 PM

6 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Is it running different? Misfiring or anything? Check engine light on? This noise happen at idle? Or when driving?
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Saturday, March 6th, 2010 AT 5:08 PM
Tiny
GEOVERJAM
  • MEMBER
  • 4 POSTS
No, the engine is not misfiring. I had it checked with an OBD2 scanner and ASE mechanic friend at the military base autohobby shop can't find anything wrong. The noise is only when engine is cold, after it warms up even at idle. Noise goes away.

I listened to it again yesterday and the noise is more pronounced at the lower section of the right side of the engine (as heard from the right wheel well).
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Monday, March 8th, 2010 AT 8:12 AM
Tiny
GEOVERJAM
  • MEMBER
  • 4 POSTS
The vehicle is not running differently. And the noise persist even more when driving as the engine is running at higher rpm. The noise however, goes away after a few miles of driving or when the engine gets to a higher temperature.

There was a check engine light but went away after I restarted the engine. The check engine light showed up over 3 mos back and never occured again.
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Monday, March 8th, 2010 AT 8:18 AM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Check the exhaust for loose heat shield and broken welds on the shield where they are welded to the pipes and converter.
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Tuesday, March 9th, 2010 AT 3:17 PM
Tiny
GEOVERJAM
  • MEMBER
  • 4 POSTS
Thank you for pointing me to the heat shield. I finally got the problem fixed. The noise was from a leaking exhaust manifold due to busted two aft mounting bolts. It was a quick fix ($46 for replacement bolts and gasket and 2 hours of my time.)
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Sunday, March 14th, 2010 AT 4:58 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Good work!
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Sunday, March 14th, 2010 AT 7:09 PM

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