Engine Vibration?

[Kalevera]

The v8 harmonic balancers DO go bad, but the engine would likely stall or sputter at anything above ~ 2700 rpm.

Sure you don't have a collapsed engine or trans mount?

best, whit

[632 Regal]

Great reminder Whit! Bad mounts really can transmit some vibration.

[baileydog]

I did check both the transmission and the engine mounts, and they all seemed to check out.
I did replace the transmission output shaft bearing and the bearing halfway down the driveshaft, so it seems to me that there has been some problems in the past with the driveline.
Does it make any sense that the torque converter has a bad bearing or bushing, thereby creating a vibration. BMW did have a bulletin out mentioning a failure here.

,

[mattyb]

the centre bearing and flex disc are due at about 200k anyways. who did them and was the shaft put back on correctly? how did u check the tranny mounts and the engine mounts? if u dont lift em all the way up, especially the engine mounts u wont know. my money is on the engine mounts before heading into other complicated stuff. if the engine mounts havent been done for a while then its not going to hurt to do them. they are cheap and quick to do and then start looking for a vibration if there is still one.

[baileydog]

We checked the engine mounts at my local (they are pretty good, I get to be there at all work) the mounts were checked with a bar and prying.

I will however change the engine mounts, the tranny mounts were done when the flex bearing was done.

Thanks bud,

[mattyb]

u can drop the front plastic protective plate and under the front of the sump it is safe to put a block and then jack it right up from that point. its the only way to really see what the mounts are doing. i am just an amatuer and the first time i looked at the mounts i though they looked bloody brilliant. my father in law , whos a mechanic, then showed me much to my horror that when he jacked it up the mounts were completely separated. just a thought. good luck anyway

[Bill R.]

jack the motor up like that

u can drop the front plastic protective plate and under the front of the sump it is safe to put a block and then jack it right up from that point. its the only way to really see what the mounts are doing. i am just an amatuer and the first time i looked at the mounts i though they looked bloody brilliant. my father in law , whos a mechanic, then showed me much to my horror that when he jacked it up the mounts were completely separated. just a thought. good luck anyway

[mattyb]

maybe allow me to clarify because im not going to argue with that bill. i dont mean rip into the jacking and tear em apart, rather lift the engine to the point where its plainly obvious that they are good or stuffed. i found that it only took a small lift to see that they were separated, maybe 5-10 mm ,thats all

[Bill R.]

tell them and will attempt to pick up the car by the engine which will usually break the mounts.. The most common failure i see is not the mounts breaking but the mounts collapsing, since it is a hydraulic mount if it collapses you don't get any damping and vibration is transferred to the frame. And that can't be told by raising the motor with a jack.

maybe allow me to clarify because im not going to argue with that bill. i dont mean rip into the jacking and tear em apart, rather lift the engine to the point where its plainly obvious that they are good or stuffed. i found that it only took a small lift to see that they were separated, maybe 5-10 mm ,thats all

[stargazer_61]

I have a similar vibration in the same RPM range. Crawled underneath and checked the engine mounts. The looked fine. Then took it in for a wheel balance. Lo and behold! Left mount has completely separated, so guess what I am going to be doing?