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"Friends, Romans, countrymen, other E39 M5 masochists, lend me your ears!" Rod Bearings? Chain Guides? (2 videos...)

4K views 30 replies 13 participants last post by  m5 deamon 
#1 · (Edited)
Long and short I bought a "project" M5 and was assured by the PO it was an exhaust leak. I took the car to a VERY reputable shop (Lambo, Ferrari, high end work and the owner has an E39 M5) for a PPI and SPECIFICALLY requested they check to make sure the noise wasn't Rod Knock or Chain Guides. They felt it was an exhaust leak and nothing too serious. Fine I trust them and could see how that makes sense

Trusting them and a few other mechanics I had listen to it I went through with the purchase (it was too cheap not to...).

Symptoms:
- Cold Startup - noise for a couple seconds then it subsides (tensioner pressuring my guess)
- Revving (cold or hot no difference) - Noise that goes up and down with RPM. It is consistent and doesn't seem to varying in tempo or "clatter." Audible from outside the car (i.e. embarrassing...)
- It is NO load dependent and is on accel and decel.
- Clutch engagement has NOT effect on noise (i.e. always there...)
- Sound originally appeared to be coming from the top but after videoing (below) seems more bottom rear?
- Occasionally a "rumble" from the flywheel area heard IN the car

To date I've done the following:

- O2 sensors (and welded bungs)
- Spark Plugs
- ALL CPS sensors
- Guibo, CSB, shift linkage
- A couple oil changes with 10w60 (some light non-ferous) pieces like a grain of sand not "shards" in the oil filter...
- Bank 1 exhaust manifold gaskets (one was clearly leaking)
- Exhaust 'donuts'
- Exhaust mounts
- VANOS board maintenance
- LOWER chain tensioner
- Belts

I'm (unfortunately) leaning towards rod bearings or chain guides. Or hell, maybe both...

https://www.youtube.com/watch?v=IA09RwL-dg4

https://www.youtube.com/watch?v=kmXLVOEQnzY
 
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#3 ·
That was my initial thought from the clatter on startup, some small aluminum particles (I assume from chain hitting the cover near the oil pump?), and how consistent it is with RPM. Even though it is a MUCH larger job, I'd much rather it be guides.

If rod bearings and it being run for who knows how long by the PO and admittedly a few thousand miles by myself (...thinking it was NOT rod or guide related according to the PPI) I'm sure the crank would be damaged and who knows what would happen to the rods, and other from lowered oil pressure...
 
#4 ·
Mileage?

That doesn't sound like rod bearings. Sounds more like lifters honestly.
 
#5 · (Edited)
148k

Ah, how could I forget theory #3! I thought that too. I followed the "rev" procedure to try to ensure it was pumped up, I've driven it at high revs to try to pop loose if one is collapsed, have done a few oil changes and even threw in some Rislone to help "clean" the motor a bit.

Nada. I do know the car sat for about a year and was hoping that might be it too but I know a collapsed lifter is incredibly rare. Still, better than rod bearings.
 
#6 · (Edited)
"Friends, Romans, countrymen, other E39 M5 masochists, lend me your ears!" Ro...

Model year and miles on car would be helpful information. Since you said this car sat for a year I'd be inclined to put a lighter oil (say 5W-30, 5W-40 or 0W-40) in it and give it an Italian tune-up before tearing into engine. Dropping the lower oil pan might be advisable to see if there's any pieces of chain guide there.
 
#9 ·
It sounds like your oil is low. Check your level. Or it sounds like oil is not staying up in your system. Dry start. I think these cars have a system that keeps your oil up in the vanos so u won't have that dry start sound in the mornings. That sound is also similar to broken chain guides I had in my 740i.

Just some thoughts...
 
#10 · (Edited)
So a bit of an update...

I pulled off the Bank 1 valve cover and noticed that the tensioned side of the chain (outer most Bank 1 side) was taunt, however the one that has the chain going down the V of the block (medial) was quite loose which seemed odd. No debris, broken bits and the guides actually looked quite good. I did however notice that the guide has slight play going side-to-side (front to back oriented to the engine).

Fast forward to the other night and I pull the Bank 2 valve cover. Pretty much speaks for itself. There are three quite well grooved "witness" marks on the inside of the cover. My thought is that the guide at the bottom of the V has broken but the upper parts still look "ok." I haven't dropped the pan yet but I anticipate seeing some plastic guides. This also proves why I found a slight bit of non-ferous metal in my oil filter.

The only other thing I could think of would be that timing is really thrown by the VANOS plate on Bank 1 (rotated a few degrees clockwise?) that has tensioned the outer part of the chain and allowed for slack on the medial side. Honestly I don't even know if that is possible but that is the only other thing beside the guides I can think of...

Looks like chain guides at in my future. Not exactly something I'm thrilled about...

https://www.youtube.com/watch?v=jV0pQnaRqio








 
#18 ·
The only other thing I could think of would be that timing is really thrown by the VANOS plate on Bank 1 (rotated a few degrees clockwise?) that has tensioned the outer part of the chain and allowed for slack on the medial side. Honestly I don't even know if that is possible but that is the only other thing beside the guides I can think of...
FYI the people currently installing a second hand motor for me have replaced the timing chain and reported the old one appears to be significantly stretched, to the extent that the tensioner couldn't take up all the slack - apparently they've taken a photo of the difference between the old and new chain, but I've not got it yet to post up.
 
#12 · (Edited)
Yep. I have a 27mm wrench coming, a nice new mirror on a stick and a 32mm to better help turn the crank.

The only thing I need now is time! It likely will be a few hours here, a few there but eventually it'll get done! Maybe I'll suggest the wife and kids go to her parents for the weekend while I do yard work; aka hire a few locals while I get greasy!
 
#14 · (Edited)
When you say you replaced the lower tensioner you mean the one on the pass side accessible from the outside? Did it make an appreciable change?

That start is still loud, did you use a compressor when you blew out the noids or just those dumb cans? Can you turn your compressor up to say 150PSI?

I would do the board maintenance again and soak the noids in kerosene and during some periods of soaking spend 5 mins on each noid activating it rapidly. Repeat this a few times in the soak 24 hrs min a week would be better and activation once a day.

If there was a change when you installed the tensioner then you could have a bit of damage to the guides but not destroyed the oil tensioner and chain is also worth a look, my vote pull the pan.

It is not rod knock as that gets much loader as the RPM come up, very annoying by 2500.
 
#15 · (Edited)
Sailor, thanks for the reply. I was hoping to get the likes of you, vantaam, 68FB, etc. in on this.

Yes that is the tensioner I replaced. It made a small but insignificant difference to the sound.

When I cleaned the noids I did not have a high PSI air supply like I do now. I haven't received ANY VANOS related codes however since the cleaning and the motor has run very, very well. I'm curious why you believe it may be the VANOS units. Do you believe they aren't supplying enough pressure to properly control the timing of the cams? Wouldn't that throw a code? I did just place an order for guides and VANOS rebuilds including the spring plates so I might as well let the noids soak for a while.

I'll be pulling the pan soon. I need to run by Autozone and dump my cans to make room for emptying the oil and likely coolant too. I'm assuming I'll find guide pieces, but I'm hopeful the oil pump and filters will be ok.

Also the noise IS very annoying off idle up to 2500-3500 where it is drowned out by other motor noise. In the vidoes I posted some revs are up to 3000. It can be heard from both inside and outside the car but appears to be tightly tied to RPM and is consistent. I had another shop foreman at a reputable BMW shop listen to it and he thought lifters...
 
#17 · (Edited)
I will give you two usual's because I did not really hear it in the motor, but I suck at videos. Rear exhaust mounts under the back seat. If orange likely noise maker for the cab if black then they are updated. Oil filter mounts same make more noise in the cab as the rpm rises. Rod bearings are fairly obvious they are loud outside and you get the sudden urge to shut the motor off now.

As far as the vanos noise goes at startup, it is very simple and the accum makes up for this fault but the fault is still the same. When you shut the motor off the noids close this should trap pressure around the Vanos piston. The noise is the vanos piston slapping the cover plate. If the noids leak then the oil leaks out allowing the slapping. I am not talking about holding a lot of pressure just keeping oil in around the piston.
You can tell how leaky by starting the engine warm in timed intervals after shutdown. 5 min no noise 20 min noisy 30 min very noisy. The closer to 5 min you get noise the worse they leak. They should not make noise except for a little rattle after sitting a day or so. If my car sits 3 days I get rattle on startup and it is a 2000.

Some noids just leak from wear but if they are still pretty good then you live with it.
 
#20 · (Edited)
Rear exhaust mounts are brand new. I replaced them about a month ago when I had the exhaust down to do Bank 1 manifold gaskets and driveshaft rebuild. Oil filter mounts are new as well and the sound doesn't emanate from either. The sound is quite loud anywhere above 1000rpms but most who hear it lean towards lifter. I'm curious if how the chain is slapping it is 'echoing' all around is mimicking something else.

I'll definitely soak and rebuild what I can in the VANOS when I pull it soon. It very well could be that but the "grooves" left by the chain on the Bank 2 cover show the chain is definitely making solid contact; and from the looks of it quite severe.

FYI the people currently installing a second hand motor for me have replaced the timing chain and reported the old one appears to be significantly stretched, to the extent that the tensioner couldn't take up all the slack - apparently they've taken a photo of the difference between the old and new chain, but I've not got it yet to post up.
Ouch that is no good but glad they caught it! I'm replacing the main, 2 cam chains and oil pump chain tool Might as well while I'm in there.

Better guides than crankshaft, no?

Guides are just time (and timing) - if you take a week and do some every day it's not too bad, I would imagine. I take that approach now on anything with my E60 M5. It just seems to make it easier to work through the unexpected roadblocks that keep coming up in a DIY on that car.
Yes definitely better guides than crankshaft! AI'm throwing around the idea of doing the rod bearings too since the car is at 148k. I kind of might as well since I'm in there and will be pulling the lower pan and oil pump already. I'd rather be safe than sorry and ensure I'm pulling any contaminants I can.

I wish I had the ability to do it all in one go but it likely will be an hour here, and hour there. I do agree sometimes that is a good way to do it and just break it out in chunks. I can prepare and research individual steps and hopefully not hit too many snags...
 
#21 · (Edited)
Finally got a 32mm to be able to turn the crank and noticed at certain points in the cycle the main chain AND bank 1 chain between the cams that was previously loose tightens up. As I kept rotating the crank I found it would tighten and loosen at certain points. The lower tensioner/rail on bank 1 appeared tight the whole time. Is this normal? Maybe because of hydraulic pressure going up and down? Still a bit odd as the tensioner railed felt taunt.

I'd assume it would have uniform tension and not REALLY loosen to the point of hitting the inside of the front cover of Bank2 as shown above. Possible the chain stretched at certain points? I'm kind of at a loss unless there is some odd play with the VANOS Sailor as you mentioned.

One good thing though is of the chain did tighten as it has I believe the tensioners are good along with the rails possibly. Still going to drop the pan and check next though.
 
#24 ·
Yet another update. I was able to drop the pan the other evening and a couple notes:

1) NO chain guide pieces, metal pieces, etc. in the pan itself
2) Unfortunately my excitement was short lived once I pulled off the oil pump filter. While not bad, there were some small pieces of guide I assume are from where the U shaped one "clipped" to the metal structure. The other metal is NON-ferrous and I couldn't see where it separated from.
3) The oil was pretty clean with no flakes or other material. I did find some small pieces of alum in the filter (VERY few) which is explained by the front cover above AND the oil pump cover shown below
4) The oil pump chain was INCREDIBLY loose and the tensioner didn't seem like it was doing much at all. I'm not sure if the tensioner is bad, or if the chain is stretched. I could easily klack it against the metail around it quite loudly.
5) The oil pump chain cover was REALLY dug into by the chain. I'm going to assume this is where all of the noise has been coming from. It makes sense as it if low and sounded like it was bouncing around the bottom.
6) I took two samples: 1 for blackstone and one for myself. The one for myself I dropped a strong magnet in and swirled it around for a while, removed it to inspect and didn't see anything on the magnet indicating rod bearing flakes, etc. I then wiped it clean with a lint-free wipe and found NOTHING there either.

While I think overall I dodged a bullet, I'm still a bit wounded. While I don't think the guides have explosively failed, it does seem they're close and the oil pump chain was my warning 'heads up' before they REALLY let go.

Can anyone ID the metal specifically?




 
#25 ·
The wear on the oil pump cover seems normal because the chain has stretched and the spring in the tensioner is a stupid design. But the plastic bits are your guides. I would pull the vanos units and upper timing covers leave the lower oil pan off and have a good look. My bet is the guides the rubber is old silicone from someone doing valve cover gaskets.
 
#26 ·
Yeah the silicone I believe is from where someone did valve cover gaskets as you mentioned. When I pulled off Bank 1 there was similar silicon just inside of the cover.

The oil pump REALLY surprised me though. I hadn't expected it to stretch that much and the tensioner is about useless. I wish the chain wasn't apt to stretch unlike the duplex chain so I'm just going to replace everything. The plastic pieces I'm 99% sure are the tabs for the u-piece and if they're broken I'm sure the rest of the rail isn't too far behind anyway. I believe there are 10 "tabs" total and I'm down at least 3...
 
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