Main Bearing, Vanos, or Something Worse?

[DrFerry]

Originally Posted by bm99

Honestly this is very similar to the noise I was hearing in my car, only to discover that my exhaust was cut clean through on one side: https://www.bimmerpost.com/forums/sh...php?p=31834091

If you haven't yet, check to make sure everything is looking good with the exhaust.

Thanks for your interest. No cuts or clips like in your post linked above and in your photo I've embedded below. In fact for mine almost the entire exhaust has been replaced i.e. removed my M3World.com.au X-Pipe and replaced it with prior OEM X-Pipe. Your location says ATL. It looks like in your photo (below) someone might've tried to steal your cats? Or was that a joy the previous owner experienced.
.

[bm99]

Originally Posted by DrFerry

Thanks for your interest. No cuts or clips like in your post linked above. In fact almost the entire exhaust has been replaced i.e. removed M3World.com.au X-Pipe and replaced with prior OEM X-Pipe. Your location says ATL. It looks like in your photo (below) someone might've tried to steal your cats? Or was that a joy the previous owner experienced.
.

Lol the previous owner said his 19 year old kid was driving this car, but he suddenly wanted to get rid of it after only a year... I have a strong feeling that buddy got his BMW privileges taken away for chopping the exhaust off, so dad made him slap it back on and sold the car.

[DrFerry]

Originally Posted by bm99

Lol the previous owner said his 19 year old kid was driving this car, but he suddenly wanted to get rid of it after only a year... I have a strong feeling that buddy got his BMW privileges taken away for chopping the exhaust off, so dad made him slap it back on and sold the car.

Truth can sometimes be stranger than fiction.

[DrFerry]

Good news. It was indeed the engine mounts! Thank you to all the knowledgeable people who weighed in on this issue especially Redd, Brandoch, drwankel and spammysammich. The rattling and knocking is totally gone now. In fact, the car feels much smoother and far better isolated (NVH). Upon removal and inspection the Vibra-Technics engine mounts failure mode appears to be not just heat related, but also engine oil related...

My valve covers are still original OEM stock, and even though the valve cover gaskets have been replaced at least twice, if not three times, in 145K miles, they leak - more like seep. Over time, oil seeps down on to the header heat shields and then onto the engine mounts. Come to think of it,this failure mode could also be why the life of the OEM mounts is short lived i.e. because the oil degrades the synthetic rubber compound strain properties of the Vibra-Technics mount insert.

Below is a photo of one of the mounts. As I understand the design, the Vibra-Technics mount damps in both compression and rebound by acting like a bellows. As the rubber insert degrades from heat and chemical attack, the rubber separates and tears. It's possible the rubber compound being used by Vibra-Technics for the mount insert is excessively porous to engine oil.

Anyway, all is well again and no more nasty engine rattling or knocking giving me anxiety, sleepless nights, and emptying my bank account. Along the way to solving this noise issue; the DME tune was flashed back to stock, the exhaust X-Pipe was returned to stock, both timing chain tensioners were replaced, all four vanos solenoids were replaced, and both engine mounts were replaced. $$$

So the moral of the story is A) If you hear odd S65 rattling / knocking it could be your engine mounts B) If your valve cover gaskets leak then your engine mounts will probably wear out prematurely, C) Vibra-Technics engine mounts are crap for the S65 M3 application.
PS:
I could try to dismantle the mounts and analyze further but I think the photo says it all. Thanks again folks.

[Brandoch]

Originally Posted by DrFerry

Good news. It was indeed the engine mounts! Thank you to all the knowledgeable people who weighed in on this issue especially Redd, Brandoch, drwankel and spammysammich. The rattling and knocking is totally gone now. In fact, the car feels much smoother and far better isolated (NVH). Upon removal and inspection the Vibra-Technics engine mounts failure mode appears to be not just heat related, but also engine oil related...

My valve covers are still original OEM stock, and even though the valve cover gaskets have been replaced at least twice, if not three times, in 145K miles, they leak - more like seep. Over time, oil seeps down on to the header heat shields and then onto the engine mounts. Come to think of it,this failure mode could also be why the life of the OEM mounts is short lived i.e. because the oil degrades the synthetic rubber compound strain properties of the Vibra-Technics mount insert.

Below is a photo of one of the mounts. As I understand the design, the Vibra-Technics mount damps in both compression and rebound by acting like a bellows. As the rubber insert degrades from heat and chemical attack, the rubber separates and tears. It's possible the rubber compound being used by Vibra-Technics for the mount insert is excessively porous to engine oil.

Anyway, all is well again and no more nasty engine rattling or knocking giving me anxiety, sleepless nights, and emptying my bank account. Along the way to solving this noise issue; the DME tune was flashed back to [...]

Fck yes!!!

[Redd]

Great that you finally solved this mystery! VT mounts are just rubbish. Mine weren't even exposed to oil and they died.

[Andreweatstacos]

Awesome news! I've been sticking to the information you sent me a couple years ago for warm up and daily driving habbits so good thing that wasn't related. Glad you got it fixe. Any plans to re-tune it?

[DrFerry]

Andreweatstacos Thanks. No plans at the moment to re tune it.

[drwankel]

Originally Posted by DrFerry

Good news. It was indeed the engine mounts! Thank you to all the knowledgeable people who weighed in on this issue especially Redd, Brandoch, drwankel and spammysammich. The rattling and knocking is totally gone now. In fact, the car feels much smoother and far better isolated (NVH). Upon removal and inspection the Vibra-Technics engine mounts failure mode appears to be not just heat related, but also engine oil related...

My valve covers are still original OEM stock, and even though the valve cover gaskets have been replaced at least twice, if not three times, in 145K miles, they leak - more like seep. Over time, oil seeps down on to the header heat shields and then onto the engine mounts. Come to think of it,this failure mode could also be why the life of the OEM mounts is short lived i.e. because the oil degrades the synthetic rubber compound strain properties of the Vibra-Technics mount insert.

Below is a photo of one of the mounts. As I understand the design, the Vibra-Technics mount damps in both compression and rebound by acting like a bellows. As the rubber insert degrades from heat and chemical attack, the rubber separates and tears. It's possible the rubber compound being used by Vibra-Technics for the mount insert is excessively porous to engine oil.

Anyway, all is well again and no more nasty engine rattling or knocking giving me anxiety, sleepless nights, and emptying my bank account. Along the way to solving this noise issue; the DME tune was flashed back to stock, the exhaust X-Pipe was returned to stock, both timing chain tensioners were replaced, all four vanos solenoids were replaced, and both engine mounts were replaced. $$$

So the moral of the story is A) If you hear odd S65 rattling / knocking it could be your engine mounts B) If your valve cover gaskets leak then your engine mounts will probably wear out prematurely, C) Vibra-Technics engine mounts are crap for the S65 M3 application.
PS:
I could try to dismantle the mounts and analyze further but I think the photo says it all. Thanks again folks.

Regarding the repeated valve cover gasket leaks.... time to bite the bullet and get some new valve covers.

Almost every shop I talked to refuses to do valve cover gaskets only because they always end up leaking again.

I replaced my valve covers about 13,000 miles ago, and they are bone dry.

Glad you got the noise sorted out!

[DrFerry]

Originally Posted by drwankel

Regarding the repeated valve cover gasket leaks.... time to bite the bullet and get some new valve covers. Almost every shop I talked to refuses to do valve cover gaskets only because they always end up leaking again. I replaced my valve covers about 13,000 miles ago, and they are bone dry. Glad you got the noise sorted out!

Thanks. I agree about replacing the valve covers. It's a job that's way overdue. What brand of valve cover did you choose to go with? NRW or something else.? It seems the valve cover grommets on the cover bolts also have an issue i.e. they soften up over time.

[drwankel]

Originally Posted by DrFerry

Thanks. I agree about replacing the valve covers. It's a job that's way overdue. What brand of valve cover did you choose to go with? NRW or something else.? It seems the valve cover grommets on the cover bolts also have an issue i.e. they soften up over time.

I went OEM. Comes with all bolts, grommets and gaskets in a single unit and includes new oil separators.

These newer aluminum replacement options have only really been on the market for the last 1-2 years, so it wasn't really available when I did mine.

It also brings concerns on long term reliability of these new units. There is simply no data yet.

If I had to do this job today, I would probably still go OEM. 4 years from now I might have a different answer.

[GORDON.M3]

I haven't been on the forums as much as I use to be but I'm glad I saw this post and was going to mention if it wasn't motor mounts it could be the donut gasket/flange to the xpipe. In the past I have something similar when the car was completely stock without the rod bearings done. I was initially worried it was the engine bearings or something more serious. I ended up changing out the donut gasket and the sound was completely gone solving that problem. But then the following week I did my rod bearings and long behold the motor mounts literally fell off/separated as we were removing them.

Regardless of engine oil getting on to the motor mounts, the VT motor mounts aren't known to hold up well. I have spoke with a few members in the past that had them in their other cars and also mention that they have seen per-mature failures from those VT motor mounts in general. That being said, they just recommend using OEM mounts and regularly servicing them every 40k miles.

[DrFerry]

Originally Posted by GORDON.M3

I haven't been on the forums as much as I use to be but I'm glad I saw this post and was going to mention if it wasn't motor mounts it could be the donut gasket/flange to the xpipe. In the past I have something similar when the car was completely stock without the rod bearings done. I was initially worried it was the engine bearings or something more serious. I ended up changing out the donut gasket and the sound was completely gone solving that problem. But then the following week I did my rod bearings and long behold the motor mounts literally fell off/separated as we were removing them.

Regardless of engine oil getting on to the motor mounts, the VT motor mounts aren't known to hold up well. I have spoke with a few members in the past that had them in their other cars and also mention that they have seen per-mature failures from those VT motor mounts in general. That being said, they just recommend using OEM mounts and regularly servicing them every 40k miles.

Thanks for taking the time to reply and share your thoughts. I can see how a loose exhaust do-nut flange (in between the header flange and down pipe) could rattle and knock in a very similar way to a failed vibra-technics engine mount. The vibra-technics engine mount uses a solid metal case for the rubber mount, as well as a metal disc as part of the mounting bolt. In hindsight, the VT design is an awful design and far too complex for the task at hand. Not to mention the metal case of the mount acts like an oven for the rubber insert since it's located smack bang next to the headers! Yes, case closed and thank The Lord the NVH is now back to OEM level.