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ron
12-18-1998, 02:20 PM
Just recently I've noticed my car seems to have a (very)slight vibration when stopped in gear (waiting for a light). Not a noise, just a steady dull vibration, almost like a rough idle. A friend suggested one of my motor mounts may have went bad. I'm leaning more toward maybe a tranny mount since the buzz drops right off when the car is running in park. What do i look for or check, and do any of you 5ers have suggestions/had similar problem? TIA<p>ron <br>89 525iA (yes, it's a slushbox)

GA
12-18-1998, 05:09 PM
I don't know how you drive your car, but I've been told that the condition you describe can be caused by the build-up of deposits in your engine if you never run it at high RPM's. This may or may not work, but try running your engine at 4k-5k+ rpm's for a few minutes on the highway (putting your slushbox in a lower gear will obviously help you accomplish this) to really heat your engine up and make it breathe. This may blow out some of those alleged deposits. If it works, your car's idle will be relatively smooth again. If not, it only cost you a few cents in gas.<p>-GA<br>'95 525iA<p><br><i>: Just recently I've noticed my car seems to have a (very)slight vibration when stopped in gear (waiting for a light). Not a noise, just a steady dull vibration, almost like a rough idle. A friend suggested one of my motor mounts may have went bad. I'm leaning more toward maybe a tranny mount since the buzz drops right off when the car is running in park. What do i look for or check, and do any of you 5ers have suggestions/had similar problem? TIA<p>: ron <br>: 89 525iA (yes, it's a slushbox)<p></i>

Vikram
12-18-1998, 10:21 PM
Ron,<p>I had noticed the same symptoms on my 93 525i. It stopped after I switched to synthetic fluids for the car - which may be purely co-incidental. The car has 81k miles on it.<p>Regards,<br>Vikram<br>93 525iA

Jose
12-19-1998, 10:50 AM
<p>: I don't know how you drive your car, but I've been told that the condition you describe can be caused by the build-up of deposits in your engine if you never run it at high RPM's. This may or may not work, but try running your engine at 4k-5k+ rpm's for a few minutes on the highway (putting your slushbox in a lower gear will obviously help you accomplish this) to really heat your engine up and make it breathe. This may blow out some of those alleged deposits. If it works, your car's idle will be relatively smooth again. If not, it only cost you a few cents in gas.<p>: -GA<br>: '95 525iA<p>: <br>: : Just recently I've noticed my car seems to have a (very)slight vibration when stopped in gear (waiting for a light). Not a noise, just a steady dull vibration, almost like a rough idle. A friend suggested one of my motor mounts may have went bad. I'm leaning more toward maybe a tranny mount since the buzz drops right off when the car is running in park. What do i look for or check, and do any of you 5ers have suggestions/had similar problem? TIA<p>: : ron <br>: : 89 525iA (yes, it's a slushbox)<p>Mine was having the same problem, If you can call this a problem, but anyways, I drove to Northen CA (5 hour drive) at high RPM and when I came back I told my wife that thats what the bimmer needed it, because it started to run smoother.<p>Jose<br>

Jay
12-19-1998, 02:23 PM
<i>: Just recently I've noticed my car seems to have a (very)slight vibration when stopped in gear (waiting for a light). Not a noise, just a steady dull vibration, almost like a rough idle. A friend suggested one of my motor mounts may have went bad. I'm leaning more toward maybe a tranny mount since the buzz drops right off when the car is running in park. What do i look for or check, and do any of you 5ers have suggestions/had similar problem? TIA<p>: ron <br>: 89 525iA (yes, it's a slushbox)<p></i>I have had the same problem on my 90 535 auto for a while now. My car now has 65k miles but I remember noticing the vibration first way back in 93 after I had just purchased the car used (from a BMW dealer with maintenance records) with only about 20k miles. For some reason I didn’t observe the vibes during the test drive – I guess we didn’t stop at any lights long enough for me to notice the symptoms. Anyway just as you described, the vibration is noticeable at idle at a stoplight with the trans in drive. To that I add that the vibes I notice are actually a combo of driveline vibe and some noise from interior pieces buzzing in resonance - I've traced slight buzzing from the dashboard and center console (especially if you have change and other trinkets there). When the AC is on these symptoms are more pronounced. <p>When shifted to neutral or park the vibes and buzz go away. But the engine does idle with a certain sharp edge to it. Not exactly rough but a kind of brutish character, like a supressed snarl. Based on some informal census I’ve done it seems that this idle NVH (noise, vibes and harshness) level is normal for BMW 6 cyl SOHC engines of the same family (non-“eta” type, eg. 1985 528e). I’ve talked to a number of BMW owners with this engine type (325, 525, 535 and 735), and test-driven a number of their cars (with mileages ranging from 25k to 75k) and noted the same idle vibrations and buzz. In fact one time I was at my dealer and they allowed me to observe the idle character of the 88-90 5’s and 7’s in the service lot. I checked only the cars that recently had their Inspections (I or II) done. I checked about eight cars and noticed that all had the same idle character as mine – same sharp edge in neutral or park, same vibes and buzz for autos in drive. <p>It’s most likely that this idle character comes from the agressive cam timing of these engines. It also looks like the auto transmission is set for minimum torque converter slip, probably to eliminate driveline lash (which is virtually nonexistent). All of these design elements are consistent with the overall sport nature of the car. But when such an engine is hooked up to such an automatic and the engine is loaded at idle the transmission will not allow much slip and so the vibes result. <p>It may also benefit you to know that earlier I did not think this way, and sought measures to eliminate or reduce the “stoplight vibes”. Back then I thought there was something wrong with my engine. Here are the remedies I tried/considered: <br>1. Engine and trans oil change with an engine oil additive designed to reduce NVH – This was the first fix suggested by both my indep mechanic and dealer. Didn’t produce any noticeable improvement.<br>2. Valve adjustment – By dealer. Didn’t work either. Per dealer the valves were not out of adjustment.<br>3. Motor and trans mounts - Just like you I thought of replacing the motor or trans mounts. But according to both my indep mechanic and BMW dealer the mounts are fine, so we passed. Which was expected given the young age and low mileage of the car.<br>4. Switch to higher octane fuel – In the past I used regular unleaded, as allowed by the manual. I asked two indep mechanics and two dealers whether switching to premium would work, and was surprised to receive a split vote – one indep and one dealer said yes, while the other indep and dealer said no. The dealer who said no said that my engine would not behave any differently on premium. I decided to switch anyway out of curiosity. Produced a slight though noticeable reduction in “stoplight buzz”, no change in unloaded idle. <br>5. A friend suggested raising the idle level but I rejected the idea. I prefer to stay with factory specs as much as possible.<p>It’s interesting to note that the newer BMW DOHC sixes and V8s don’t have these same vibes. I’ve checked out a 94 525, a 98 328, and a 95 740 and noted that their engines have a level of NVH islolation not known to the SOHC sixes. The 98 328 especially, idled imperceptively with the trans in either neutral or drive at a stoplight. I could not detect any change in the NVH level at either settings. Very refined idle setting, totally different from mine. My indep mechanic and BMW dealer agree.<p>Overall, I like the agressive idle of my engine, and I can live with the “stoplight buzz” – I think it’s a good tradeoff for no driveline lash. In fact, the agressive idle was one of the elements that attracted me to this car back in 93 when I was shopping for a sports sedan and was looking at the BMW 5 series, Lexus GS 300, MB 300E, and Nissan Maxima. I liked all these cars but the 535 won me over when one time, after test driving it I stepped out of the car for a minute just to have a look and walk around. I had left the engine running and could hear it’s muted growl. It was then that I noticed that this car idled more like a hotrod than a sedan. I knew right then and there that this was the car for me.<p>Anyway, back to you Ron - I am curious about one thing – at what mileage did you first observe the stoplight vibration? If your driveline did not have this buzz before and now it has it then maybe it’s a failed part. In that case hope my experience helps you somewhat.<p>Good luck and let me know what happens.<p>Jay<br>90 535A<br>

ron
12-29-1998, 12:34 PM
<i>: : Just recently I've noticed my car seems to have a (very)slight vibration when stopped in gear (waiting for a light). Not a noise, just a steady dull vibration, almost like a rough idle. A friend suggested one of my motor mounts may have went bad. I'm leaning more toward maybe a tranny mount since the buzz drops right off when the car is running in park. What do i look for or check, and do any of you 5ers have suggestions/had similar problem? TIA<p>: : ron <br>: : 89 525iA (yes, it's a slushbox)<p>: I have had the same problem on my 90 535 auto for a while now. My car now has 65k miles but I remember noticing the vibration first way back in 93 after I had just purchased the car used (from a BMW dealer with maintenance records) with only about 20k miles. For some reason I didn’t observe the vibes during the test drive – I guess we didn’t stop at any lights long enough for me to notice the symptoms. Anyway just as you described, the vibration is noticeable at idle at a stoplight with the trans in drive. To that I add that the vibes I notice are actually a combo of driveline vibe and some noise from interior pieces buzzing in resonance - I've traced slight buzzing from the dashboard and center console (especially if you have change and other trinkets there). When the AC is on these symptoms are more pronounced. <p>: When shifted to neutral or park the vibes and buzz go away. But the engine does idle with a certain sharp edge to it. Not exactly rough but a kind of brutish character, like a supressed snarl. Based on some informal census I’ve done it seems that this idle NVH (noise, vibes and harshness) level is normal for BMW 6 cyl SOHC engines of the same family (non-“eta” type, eg. 1985 528e). I’ve talked to a number of BMW owners with this engine type (325, 525, 535 and 735), and test-driven a number of their cars (with mileages ranging from 25k to 75k) and noted the same idle vibrations and buzz. In fact one time I was at my dealer and they allowed me to observe the idle character of the 88-90 5’s and 7’s in the service lot. I checked only the cars that recently had their Inspections (I or II) done. I checked about eight cars and noticed that all had the same idle character as mine – same sharp edge in neutral or park, same vibes and buzz for autos in drive. <p>: It’s most likely that this idle character comes from the agressive cam timing of these engines. It also looks like the auto transmission is set for minimum torque converter slip, probably to eliminate driveline lash (which is virtually nonexistent). All of these design elements are consistent with the overall sport nature of the car. But when such an engine is hooked up to such an automatic and the engine is loaded at idle the transmission will not allow much slip and so the vibes result. <p>: It may also benefit you to know that earlier I did not think this way, and sought measures to eliminate or reduce the “stoplight vibes”. Back then I thought there was something wrong with my engine. Here are the remedies I tried/considered: <br>: 1. Engine and trans oil change with an engine oil additive designed to reduce NVH – This was the first fix suggested by both my indep mechanic and dealer. Didn’t produce any noticeable improvement.<br>: 2. Valve adjustment – By dealer. Didn’t work either. Per dealer the valves were not out of adjustment.<br>: 3. Motor and trans mounts - Just like you I thought of replacing the motor or trans mounts. But according to both my indep mechanic and BMW dealer the mounts are fine, so we passed. Which was expected given the young age and low mileage of the car.<br>: 4. Switch to higher octane fuel – In the past I used regular unleaded, as allowed by the manual. I asked two indep mechanics and two dealers whether switching to premium would work, and was surprised to receive a split vote – one indep and one dealer said yes, while the other indep and dealer said no. The dealer who said no said that my engine would not behave any differently on premium. I decided to switch anyway out of curiosity. Produced a slight though noticeable reduction in “stoplight buzz”, no change in unloaded idle. <br>: 5. A friend suggested raising the idle level but I rejected the idea. I prefer to stay with factory specs as much as possible.<p>: It’s interesting to note that the newer BMW DOHC sixes and V8s don’t have these same vibes. I’ve checked out a 94 525, a 98 328, and a 95 740 and noted that their engines have a level of NVH islolation not known to the SOHC sixes. The 98 328 especially, idled imperceptively with the trans in either neutral or drive at a stoplight. I could not detect any change in the NVH level at either settings. Very refined idle setting, totally different from mine. My indep mechanic and BMW dealer agree.<p>: Overall, I like the agressive idle of my engine, and I can live with the “stoplight buzz” – I think it’s a good tradeoff for no driveline lash. In fact, the agressive idle was one of the elements that attracted me to this car back in 93 when I was shopping for a sports sedan and was looking at the BMW 5 series, Lexus GS 300, MB 300E, and Nissan Maxima. I liked all these cars but the 535 won me over when one time, after test driving it I stepped out of the car for a minute just to have a look and walk around. I had left the engine running and could hear it’s muted growl. It was then that I noticed that this car idled more like a hotrod than a sedan. I knew right then and there that this was the car for me.<p>: Anyway, back to you Ron - I am curious about one thing – at what mileage did you first observe the stoplight vibration? If your driveline did not have this buzz before and now it has it then maybe it’s a failed part. In that case hope my experience helps you somewhat.<p>: Good luck and let me know what happens.<p>: Jay<br>: 90 535A<p></i>All very good answers that's why i love this site... I plan to first try the FUN advice, gas it up and drive it fast! I haven't really done any sustained highway driving with it lately. Hopefully that'll clear it out...i plan to print out a few of the answers here if i get pulled over...btw, my car's got 105k, but just had it serviced and everything checked out fine, so i too am leaning toward the deposit buid-up idea for now anyway. <br>Any of you guys wanna recommend an injector, or should i stay away from them? thanks again, and happy new year.<br>ron


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