545i low RPM rattle - VANOS??
07-06-2011, 09:50 PM
#1
So I have another thread opened about taking my car to the dealer for a diagnosis and the short of it is they didnt tell me anything. Perhaps someone else has this problem.
The car is an 04 545i 6sp with 75k miles. I purchased it about 3 months ago and noticed shortly after there is a rattle/tap when letting the clutch out or letting the RPMs go below idle (750). The rattle tap is coming from the front of the passenger side valve cover. I have the BMW DIS/Progman software and manipulated the RPMs and found that the rattle sound happens anywhere from 500 to 700rpms and is a consistant tapping/clattering. I have a feeling it has something to do with the VANOS or valvetronic system. There is not other tapping at eny RPM range except those low RPMs.
Oddly, the noise completely disapears when the AC is on so I'm suspecting the computer somehow changes the VANOS solenoid with AC or there is some computer related change.
Not sure how smooth these engines run, but you can feel a very slight shake in the shifter at idle and the tach is not perfectly still at either. Under the hood though, the engine appears as smooth as a sewing machine. Not sure if this is normal.
Any help would be greatly appreciated!
The car is an 04 545i 6sp with 75k miles. I purchased it about 3 months ago and noticed shortly after there is a rattle/tap when letting the clutch out or letting the RPMs go below idle (750). The rattle tap is coming from the front of the passenger side valve cover. I have the BMW DIS/Progman software and manipulated the RPMs and found that the rattle sound happens anywhere from 500 to 700rpms and is a consistant tapping/clattering. I have a feeling it has something to do with the VANOS or valvetronic system. There is not other tapping at eny RPM range except those low RPMs.
Oddly, the noise completely disapears when the AC is on so I'm suspecting the computer somehow changes the VANOS solenoid with AC or there is some computer related change.
Not sure how smooth these engines run, but you can feel a very slight shake in the shifter at idle and the tach is not perfectly still at either. Under the hood though, the engine appears as smooth as a sewing machine. Not sure if this is normal.
Any help would be greatly appreciated!
07-07-2011, 04:22 AM
#3
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My Ride: 2004 545i, 6-speed Manual, Silver Grey Metallic, Grey Dakota Leather, Cold Weather Pkg, Premium Sound Pkg, Sport Pkg, Lumbar Support
Mine with 47,000 miles behaves the same. Since it was associated with letting the clutch out, I suspected a clutch issue. Have not been concerned enough to investigate further...
07-07-2011, 05:36 AM
#4
Oh well it is not a clutch issue since that was my original thought and my clutch was slipping. I replaced the clutch, flywheel, pressure plate, and throwout bearing and the noise remained. The noise is definately from the front right head/valvecover area. I'll try and get a vid today.
07-07-2011, 01:37 PM
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My Ride: 05 545i
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Check all bolts,nuts fittings where the sound is coming from. I had a horrible rattle on my SRT8 after doing headers. Came to find that it was 1 lose bolt that only vibrated at really low RPM's.
07-09-2011, 10:28 PM
#7
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My Ride: Orient blue '05 545i, Sport/Premium Pkg, 6Speed MT, Xenon, Navi, Blue2th, PDC,
Before you start replacing too many parts - check the vacuum pump. When it is bad it will make tapping noise which sounds like bad VANOS.
http://realoem.com/bmw/showparts.do?...78&hg=11&fg=45
GL with repair.
Keep us updated.
http://realoem.com/bmw/showparts.do?...78&hg=11&fg=45
GL with repair.
Keep us updated.
07-10-2011, 05:51 AM
#8
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My Ride: 95 M3 CAI, chipped, pulleys, Xbrace, doesn't give headaches every time I start up!
04 545i all the goodies INCLUDING HEADACHES!
I have the same problem with an automatic. It's been doing it for a year now. It's sounds like the AC clutch or the vacuum pump. The noise stops when the AC is on and the rpm's are >500.
03-09-2012, 05:45 PM
#9
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hate to rehash an old thread.. I'm having the same problem - car makes a rattling sound around 750rpm but smooths out after it cycles down to 500rpm. My best guess is PCV Valves.. going to replace next week.. did the OP or others ever find a definitive resolution to this issue?