Engine "rattle"?
#21
11-08-2010 | 07:31 AM
Junior Member
Joined: Dec 2009
Posts: 9
From: Montgomery, Alabama
I had a similar problem, however, mine was easily traceable. It was the resonator in the exhaust system. It was a vibration that sounded like a heat shield. Something came loose inside the resonator and was vibrating. I replaced it with a magnaflow resonator and problem solved. Based on the symptoms described I am certain mine was different. Based on your symptoms it sounds exactly like low octane gas or bad gas and you are getting the "valve ping." If that is the case, try running a couple tanks of good gas with a bottle of Techron added to each. See if that makes a difference. Just a thought.
#25
06-29-2011 | 07:42 AM
Junior Member
Joined: May 2011
Posts: 27
i have a similar issue. when i am going slow and let off gas i get a rattle as well from what sounds like the driver side or middle of the vehicle. i went underneath to see if i could see anything lose or hanging, didnt find anything. noise only happens at drive at about 20mph and down. happens while the car is slowing down. no noises while in park or driving. very annoying.
08 h3 3.7L
thedave8, i get the same rattle at cold startup as well. i think its a exhaust rattle inside the resonator, becuase when it gets hot it doesnt make the sound any longer when started. but this other noise is driving me insane.
08 h3 3.7L
thedave8, i get the same rattle at cold startup as well. i think its a exhaust rattle inside the resonator, becuase when it gets hot it doesnt make the sound any longer when started. but this other noise is driving me insane.
Last edited by jtracc; 06-29-2011 at 07:45 AM.
#26
06-29-2011 | 06:06 PM
Senior Member
Joined: Oct 2010
Posts: 113
i have a similar issue. when i am going slow and let off gas i get a rattle as well from what sounds like the driver side or middle of the vehicle. i went underneath to see if i could see anything lose or hanging, didnt find anything. noise only happens at drive at about 20mph and down. happens while the car is slowing down. no noises while in park or driving. very annoying.
08 h3 3.7L
thedave8, i get the same rattle at cold startup as well. i think its a exhaust rattle inside the resonator, becuase when it gets hot it doesnt make the sound any longer when started. but this other noise is driving me insane.
08 h3 3.7L
thedave8, i get the same rattle at cold startup as well. i think its a exhaust rattle inside the resonator, becuase when it gets hot it doesnt make the sound any longer when started. but this other noise is driving me insane.
#27
09-19-2011 | 02:07 AM
Junior Member
Joined: May 2011
Posts: 2
compressor
I wonder if i have the same issue with my 2008 H3 (3.7L)...
I get a vibrating sound that I thought originated behind the glove box...it only happens when the engine hits about 900 rpms and it sounds like a resonant frequency thing....goes away when rpms are above 1100 and is quiet as can be while driving. It decides to make noise when I take off from a dead stop.
I dropped the glove box and thought it was the antenna cable against the HVAC unit -- i put my hands all over the area behind the glove box while holding the engine at 800 to 900 rpms and the rattle/vibration persisted. I wrapped every wiring harness and cable with foam tape and it still vibrates at low rpms. When I turn the blower motor to 1 or 2, I still hear it. If I turn blower motor to 3 or 4 I think it goes away -- or I just cannot hear it.
Maybe I am looking in the wrong area. I cannot tell if it is really coming from behind the glove box or the engine compartment. I read in this post that someone had their heater hoses zip tied and their "loose marbles" noise went away --- where are the heater hoses that were zip-tied????
I even insulated the module that is behind the washer fluid reservior -- it was flopping in its plastic bracket....that wasn't it.
If anyone can point me in the direction of the heater hoses, i would appreciate it.
I have silenced EVERY squeek and rattle on this vehicle except this one. My lease is up in 1 more year and I am considering just buying out my vehicle. The residual value on my contract is about $20,500 and the dealer is knocking off $1500 for people who buy their lease. This stupid noise is driving me so nuts right now that I am having second thoughts. Leaning about 70% buying out lease and about 30% buying new GMT900 ext cab 4x4 or new Colorado Crew Cab 4x4 instead.
HELP
I get a vibrating sound that I thought originated behind the glove box...it only happens when the engine hits about 900 rpms and it sounds like a resonant frequency thing....goes away when rpms are above 1100 and is quiet as can be while driving. It decides to make noise when I take off from a dead stop.
I dropped the glove box and thought it was the antenna cable against the HVAC unit -- i put my hands all over the area behind the glove box while holding the engine at 800 to 900 rpms and the rattle/vibration persisted. I wrapped every wiring harness and cable with foam tape and it still vibrates at low rpms. When I turn the blower motor to 1 or 2, I still hear it. If I turn blower motor to 3 or 4 I think it goes away -- or I just cannot hear it.
Maybe I am looking in the wrong area. I cannot tell if it is really coming from behind the glove box or the engine compartment. I read in this post that someone had their heater hoses zip tied and their "loose marbles" noise went away --- where are the heater hoses that were zip-tied????
I even insulated the module that is behind the washer fluid reservior -- it was flopping in its plastic bracket....that wasn't it.
If anyone can point me in the direction of the heater hoses, i would appreciate it.
I have silenced EVERY squeek and rattle on this vehicle except this one. My lease is up in 1 more year and I am considering just buying out my vehicle. The residual value on my contract is about $20,500 and the dealer is knocking off $1500 for people who buy their lease. This stupid noise is driving me so nuts right now that I am having second thoughts. Leaning about 70% buying out lease and about 30% buying new GMT900 ext cab 4x4 or new Colorado Crew Cab 4x4 instead.
HELP
#29
09-19-2011 | 05:14 AM
Member
Joined: Aug 2011
Posts: 67
I wonder if i have the same issue with my 2008 H3 (3.7L)...
I get a vibrating sound that I thought originated behind the glove box...it only happens when the engine hits about 900 rpms and it sounds like a resonant frequency thing....goes away when rpms are above 1100 and is quiet as can be while driving. It decides to make noise when I take off from a dead stop.
I get a vibrating sound that I thought originated behind the glove box...it only happens when the engine hits about 900 rpms and it sounds like a resonant frequency thing....goes away when rpms are above 1100 and is quiet as can be while driving. It decides to make noise when I take off from a dead stop.
#30
09-29-2011 | 02:36 PM
Junior Member
Joined: May 2010
Posts: 2
Finally found out my problem after a $100 "diagnostic" fee at a gm dealer mechanic. Turns out the rattle noise was an exhaust heat shield under the passenger side that had a crack due to broken motor mounts. Could only really be seen on a lift for whatever reason. They had to pull a "senior" mechanic because the kids in the shop which are certified couldn't figure it out. Goes to show that sometimes experienced mechanics earn their pay sometimes. They replaced in 15 minutes go figure. So ill go ahead and replace the mounts, which are not sold by local shops only the dealer and a few internet sites.