M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => General Topics => Topic started by: max123 on August 04, 2009, 03:00:53 PM
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This has been driving me nuts for months now. When I'm in 4th or 5th gear and the engine is under load around 3000rpm I get a wicked rattle from the back. No idea what it is. No loose suspension parts, the spare tire is bolted down tight.
Any suggestions? Could it be a loose trunk lid - or something worse?
Cheers
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I know what kind of rattle you're talking about, because I have the same noise, but I don't know what is, so when you find out-could you let me know.
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I'd figure it isnt a heat shield, that'd rattle at a fixed rpm regardless of load. The CSB or Diff input bearings would growl dependent on RPM and load. What kind of rattle sound is it? Like a sheet metal rattle or a growling rubbing grinding?
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I've got it too-
I think it is the tailpipe hitting the valence...
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Nope, not the tailpipe - I just replaced the rear muffler and the noise was there before and after (although that can rattle like a bastard - I had to mount mine a second time to get rid of that noise). Also, not the differential - replaced it with an LSD, and the noise was there before and after. The only two possibilities I haven't ruled out are bad subframe mounts or a worn trunklid gasket. My bet is on the trunklid - I think I may try flipping the gasket around or replacing it to see if that tightens things up.
It could be a heat shield - but that is going to be hard to isolate.
Cheers,
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Not the trunk lid. The lid is easily tightened up with a 15mm wrench - there is an adjuster bolt on the latch which can tighten or loosen the trunk - I tightened mine right down and there was no difference.
I seem to notice the noise from the rear drivers side, so I'm going to get some heat resistant expanding foam or something and make sure the heat shied on the muffler isn't the source of my pain.
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I noticed a rattle on mine today. Seems to come from the rear underside or shock tower area. New mount on a Bilstien HD. I'll check it out when it cools down a bit. 106 degrees just now... :eek:
Tomorrow, I take the 540it to work... :cool:
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BlackBMWs-could you PM me when you find this issue out, because that noise bothers me to the point of embarrassment and pulling over to "punch infant's"(Dane Cook).
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Sure can. I do know I have broken exhaust hanger muffler straps on the 318ic. These are metal ones around the muffler that the PO had welded on this muffler when the broke. I have two sets of replacement straps. I'll replace the rubber hangers when I grind the metal straps off.
As far as the shock tower area, I'm thinking it could be the new shock mounts themselves, or perhaps worn rear sway bar links.
Perhaps Thursday I can get the car up and me underneath... :cool:
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Fine - be that way. The rattle remains a mystery - thought I had it when I found a few loose bolts on a heat shield - but no.
Everything else is new, has been re-torqued, shaken, lubed - scrutinized...
She'll be rattle'n off into the sunset.
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hey check in your trunk by the jack and all that stuff i had a rattle back there to around the same rpm and gears. It ended up being the jack was not tightened down enough and was flopping around hitting up against the wall of my trunk.
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It's not a cv joint is it?
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Update: No loose stuff in trunk. I haven't got underneath for the rattles, but I did notice my sway bar ends on all corners are shot. I'll be replacing those is the next couple of weeks.
I do have something that bumps when I hit one. metal to metal, thought it migh be the vert top as it only does it when the top is up.
Still listening...:cool:
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Well, let's put our minds to work. In 4th and 5th under load at 3k, the torque being applied to the drive train is being applied for a longer period of time just because the car is already doing 40. That means the twist applied to all of the components in the drive line will stay twisted longer.
Start with your universal at the diff, then work out. Diff mounts, axels. Get a pry bar and try to move the rear end, and put a pipe wrench on the axel shafts and see how much play you have. Think of the load your engine puts on those parts at 3k in 4th and 5th gear. You can probably be pretty rough
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I recently read somewhere that E30 rear shock upper mounts can come loose and cause that rattle too. I'm afraid to look...
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URSM's are famous, but any slight thing on exhaust hardware always makes weird sounds.
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my shock-mounts were replaced, still the noise remained.
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So, I did order swaw bar links and new bushings today. I suspect that will address some of the rattling, however I still something loose around the rear passenger side folding top.
Ramblin man: I hear the ratteling in neutral coasting, no load on the drivetrain and still hear the ratteling if I his rough roads or a bump/pothole.
I'll check out the rear shock mounts before I head out to work tomorrow... :cool:
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Well I'm interested. I haven't even got to drive my car yet and if I hear noises when I do I want to know where to look first, so keep us updated.
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O.K. Replaced front and rear swaybar links and sway bar bushings. At 140k the bushings were cracked and soft and the link bushings were all cracked and soft.
After replacement, most of the mystery sounds have disappeared. What's left is what I suspect to be a Rear Shock mount failure on the real passenger side, a few sweeks in the front passenger side suspension and perhaps a loose heat shield.
I also had the exhaust mounts rewelded and a Magnaflow muffler installed. No more exhaust noises except the one I wanted with the Magnaflow...
I have a pair of Meyle RSMs coming in from UUC and will check the other sounds next weekend.
However, compared to how it was sounding over bumps, it is vastly improved. I had to listen hard to hear these last sounds.
The nice thing is that it handles much more solid after the sway bar renewal. Definately worth the time and few $.
Control arm replacements are coming up... :cool:
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Don't overlook the shock bushings.
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Don't overlook the shock bushings.
Shock bushings? as in the lower mount in the shock itself? They are about 3 months old, mounted in a pair of new Bilstien HDs. :>) I did preload the shocks before tightening the bolts on the bushings.
The RSMs were listed as OEM, but made in India from the packaging. I don't know BMW OEM part manufacturing had a location there.
Or do you mean the bushings for the upper control arms? If so, yes, I remember those as well. Is there an HD bushing available like the Meyle HDs for the 540i's?
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I was talking the lower bushing on the shock itself. A lot of times shocks will still be functionally fine but the bushings are shot. But as you pointed out you shouldn't have that problem.
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Yeah, I'm thinking the prominent sound now on bumps and right handed turns is a broken passenger rear shock mount. I have a pair of HD Meyles coming in probably Monday, so either after work or next Saturday I will swap them in.
I figure it may have punched through on a spirited right turn and hitting a pothole or bump. It is a 3 month old OEM mount with both washers in place properly. I recognize the sound from when I did this on my 533i after lowering it and swapping in Bilstien sports... I've read a number of posts after I put the mount and HDs in place how some folks have had issues. Count me in.
Thanks! :cool:
FYI - New Meyle pair of HD RSM replacements. $66 shipped to Cali from ATL with new gaskets, locking nuts and SS reinforcing plates.
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New Meyle RSMs are in and rear noises are now gone. The new drivers side MTC\Ronak RSM had broken after 4 months on new Billy HDs.
Worth the $66 bucks to fix and enjoy the absence of clunks and rattles. :cool:
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Any pics? or has it been documented to death elsewhere?
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any confirmation from others that this was the problem? I just picked up a '91 318i and it has this same problem. embarrassing yes. I thought it was the heatsheild/busted exhaust hangers as I used to have this problem in college with my '84 VW GTI. The heatshield would come loose and rattle like crazy and the exhaust hangers would snap every six months (I kept spares in my glove box). My 318 is sounding just like that now, but you all are making me thing twice, as I was already sure my shocks are shot and needing replacement.
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Are those rear shock mounts hard to put in? I think there is some discussion of this on amother board somewhere, but not lots. I have two e30s exhibiting this same issue. Where did you get the Meyle RSMs?
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check ur rear cv's almost guarentee that the problem and well ur at it change the boot kits while ur at it
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I have a few rattles too. I know the RSMs are bad, I think the 'vert or e36 mounts are firmer than the stockers.
The other thing is a loose e-brake caliper. I know it's that because it goes away when I pull the e-brake lever up a bit. I also have a shot boot, have to swap that half shaft when the weather gets better.