2003 Ford Expedition Making a bonk sound underneath car

96,000 MILES • V8 • 2WD • AUTOMATIC
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TRINABARNES
  • MEMBER
  • 1 POST
Hi,
I have a 2003 ford expedition with about 96000 miles. I have been noticing this bonk sound coming from underneath the car. I only hear this noise when I turn off the car for short intervals of time. When I re start I hear this noise. It is quite loud. Sounds like a metal can that you fill with air and release and you get a crinkling sound. I have taken it to the Ford Doctors and they have been able to hear the noise but unable to detect the cause of the problem. I do not have any driving/performance issues or the check engine light isn't on. Any suggestions? No one can seem to pin point anything!
Jul 22, 2010 at 3:55 PM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,246 POSTS
Honesly, if there are no driveability issues and they see nothing wrong, my guess is you are hearing the exhaust system expanding and contracting. Try this. Take a rubber mallot and tap on the exhaust system to see if there is anything loose in the resinator or the catalytic converter that may make the noise you hear.

let me know what you find.
Joe
Jul 23, 2010 at 5:37 PM
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