Rattle Noise when Accelerating
09-26-2010, 11:33 AM
#1
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Hi Guys.
I cruised today with the radio muted, at noticed a rattle noise when accelerating. Its not related to speed. Its there at low and high speeds, during acceleration. When i let go of speeder the noise disappear. In idle there is no noise.
My car is a 2005 e61 530d..
What could cause this?
I cruised today with the radio muted, at noticed a rattle noise when accelerating. Its not related to speed. Its there at low and high speeds, during acceleration. When i let go of speeder the noise disappear. In idle there is no noise.
My car is a 2005 e61 530d..
What could cause this?
09-26-2010, 12:12 PM
#4
Not sure which car you have-if its a 530, specifically the N52 engine and even the m54 engine--I have had, and many reports of it, are the DISA valves in the intake manifold that control which air path is open depending on which RPM band you are in--can come loose and rattle around while accerlating (since that is when they open) but when you stop accelerating they close and produce no rattle.
This took 5 times toa dealer to finally diagnosis.
It was not so much a "rattle" but a "whurring" kinda sound that was subtle but if you heard it then you could not forget it.
The check is to remove the intake manifold and inspect
THe thing is if this is missed and parts come loose inside the manifold-they get sucked into the engine and its good bye engine.
The only reason they found mine is I asked to have my spark plugs changed and they inspected the manifold as part of the service and found one of the Disa valves literally laying in the manifold completely broken off--if sucked in that would have been goodbye to the engine.
Otherwise lots of benign things cause rattling but if its only during acceleration--this is one of the fewer things that can do that. Search the web for DISA valve failure and do some reading
This took 5 times toa dealer to finally diagnosis.
It was not so much a "rattle" but a "whurring" kinda sound that was subtle but if you heard it then you could not forget it.
The check is to remove the intake manifold and inspect
THe thing is if this is missed and parts come loose inside the manifold-they get sucked into the engine and its good bye engine.
The only reason they found mine is I asked to have my spark plugs changed and they inspected the manifold as part of the service and found one of the Disa valves literally laying in the manifold completely broken off--if sucked in that would have been goodbye to the engine.
Otherwise lots of benign things cause rattling but if its only during acceleration--this is one of the fewer things that can do that. Search the web for DISA valve failure and do some reading
09-26-2010, 12:40 PM
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09-26-2010, 12:53 PM
#7
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Not sure which car you have-if its a 530, specifically the N52 engine and even the m54 engine--I have had, and many reports of it, are the DISA valves in the intake manifold that control which air path is open depending on which RPM band you are in--can come loose and rattle around while accerlating (since that is when they open) but when you stop accelerating they close and produce no rattle.
This took 5 times toa dealer to finally diagnosis.
It was not so much a "rattle" but a "whurring" kinda sound that was subtle but if you heard it then you could not forget it.
The check is to remove the intake manifold and inspect
THe thing is if this is missed and parts come loose inside the manifold-they get sucked into the engine and its good bye engine.
The only reason they found mine is I asked to have my spark plugs changed and they inspected the manifold as part of the service and found one of the Disa valves literally laying in the manifold completely broken off--if sucked in that would have been goodbye to the engine.
Otherwise lots of benign things cause rattling but if its only during acceleration--this is one of the fewer things that can do that. Search the web for DISA valve failure and do some reading
This took 5 times toa dealer to finally diagnosis.
It was not so much a "rattle" but a "whurring" kinda sound that was subtle but if you heard it then you could not forget it.
The check is to remove the intake manifold and inspect
THe thing is if this is missed and parts come loose inside the manifold-they get sucked into the engine and its good bye engine.
The only reason they found mine is I asked to have my spark plugs changed and they inspected the manifold as part of the service and found one of the Disa valves literally laying in the manifold completely broken off--if sucked in that would have been goodbye to the engine.
Otherwise lots of benign things cause rattling but if its only during acceleration--this is one of the fewer things that can do that. Search the web for DISA valve failure and do some reading
DISA valve = the famous swirl flaps?
I had my intake manifold changed as part of preventive maintenance 10 weeks ago. If it was actually the DISA valve and its loose or broken or got abnormal rod/hole play, shouldn´t be hearable in idle?
09-26-2010, 03:25 PM
#9
Yes swirl flaps are very similar to DISA valves--the butterfly valve is the same setup and it opens and closes the same. DISA refers to the one on the 3 stage/2 stage intake manifold. N52 has 3 stage and m54 has 2. You have 6 Swirl flaps I believe. The problem is a bit different but the end result is the same which is parts of plastic being sucked into an engine. I would check that immediatly as other problems may be causing this but that specific problem would be destruction of the engine and you want to rule out the bad stuff first.
09-26-2010, 09:52 PM
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Thanks for your inputs.
But as i said in #7, i had the intake manifold replaced 4000km ago as part of preventive maintenance, so I guess that could be ruled out or?
Do you know at what rpm the swirl flaps should open?
A thorough sound test this morning reviled another thing. The rattle noise start out as soon as i touch the speeder pedal and demanding some kind of acceleration. The sound is hearable at slow lower acceleration RPM (approx 1400). Higher RPM increase the rattle noise. I dont notice any loss in power.
Regards
Rasmus
But as i said in #7, i had the intake manifold replaced 4000km ago as part of preventive maintenance, so I guess that could be ruled out or?
Do you know at what rpm the swirl flaps should open?
A thorough sound test this morning reviled another thing. The rattle noise start out as soon as i touch the speeder pedal and demanding some kind of acceleration. The sound is hearable at slow lower acceleration RPM (approx 1400). Higher RPM increase the rattle noise. I dont notice any loss in power.
Regards
Rasmus