Startup Thud.
12-30-2011, 05:30 AM
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Startup Thud.
I returned home after a week yesterday and need to move the Jeep. I went to start it up and the second after it began to turn over I heard a hard thud as the engine started. It is a 2011 sport fresh oil change with 5-30 (first time, I was using 5-20 with consumption issues). Any thoughts, I am pretty sure that the dealer could not reproduce and I am not leaving it with them for a week.
12-30-2011, 11:16 AM
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Interesting, as my sons new 2012 Dodge Durango with the same engine 3.6 just started doing this also. His thud has gotten more pronounced as the temps dip and it is only upon initial start up in the morning, after that all is well. Of course the dealer had the car for 2 days and couldn't reproduce the noise,, although it has warmed up lately here. Do post if you find out any more on this as I will also.
12-30-2011, 11:38 AM
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Interesting, as my sons new 2012 Dodge Durango with the same engine 3.6 just started doing this also. His thud has gotten more pronounced as the temps dip and it is only upon initial start up in the morning, after that all is well. Of course the dealer had the car for 2 days and couldn't reproduce the noise,, although it has warmed up lately here. Do post if you find out any more on this as I will also.
12-30-2011, 12:51 PM
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Is it a rattle, or more of a single clunk? The torque converter on my old '83 Mercedes sometimes gives a clunk/thump at cold startup due to the transmission fluid being cold (mechanic said not to worry about it); is yours an auto? Also, the venerable GM 3.8L V6 (now superceeded) will often make a booming thump when it catches on initial start-up (no idea why, they just all do it) so it may just be a feature of the 60 degree large-capacity V6 design in general (though I've never noticed this sound myself on my '09 JK 6-speed).
A bad engine mount/s can also cause this thudding sound at startup when the motor catches and when under accelleration/decelleration, though I'd say your Jeep is too new to have worn or broken engine mounts (unless there was a manufacturing/assembly fault or you've banged the sump hard down on an obstacle offroad, damaging one of the mounts or brackets).
A bad engine mount/s can also cause this thudding sound at startup when the motor catches and when under accelleration/decelleration, though I'd say your Jeep is too new to have worn or broken engine mounts (unless there was a manufacturing/assembly fault or you've banged the sump hard down on an obstacle offroad, damaging one of the mounts or brackets).
Last edited by JKlad; 12-30-2011 at 02:04 PM.
12-30-2011, 05:22 PM
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Originally Posted by JKlad
Is it a rattle, or more of a single clunk? The torque converter on my old '83 Mercedes sometimes gives a clunk/thump at cold startup due to the transmission fluid being cold (mechanic said not to worry about it); is yours an auto? Also, the venerable GM 3.8L V6 (now superceeded) will often make a booming thump when it catches on initial start-up (no idea why, they just all do it) so it may just be a feature of the 60 degree large-capacity V6 design in general (though I've never noticed this sound myself on my '09 JK 6-speed).
A bad engine mount/s can also cause this thudding sound at startup when the motor catches and when under accelleration/decelleration, though I'd say your Jeep is too new to have worn or broken engine mounts (unless there was a manufacturing/assembly fault or you've banged the sump hard down on an obstacle offroad, damaging one of the mounts or brackets).
A bad engine mount/s can also cause this thudding sound at startup when the motor catches and when under accelleration/decelleration, though I'd say your Jeep is too new to have worn or broken engine mounts (unless there was a manufacturing/assembly fault or you've banged the sump hard down on an obstacle offroad, damaging one of the mounts or brackets).
12-30-2011, 05:24 PM
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Originally Posted by teh215
Where does the "thud" sound like it is coming from?
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12-31-2011, 02:55 AM
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Mine did it right after a fresh oil change but oddly enough not on a cold start. I left the dealership drove 30 miles home stopped by a store and when I came out to start it, it did it. Hasn't happened again.
2011 sport manual.
2011 sport manual.