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Discussion Starter #1
Hey everyone my m5 started making this ticking/knocking sound I cant seem to identify. Started after high rpm in 3rd gear car has 101k. I replaced the timing chain tensioner on the left side issues didnt change. No codes and it dosen't seem to have power loss. Car didnt go above 2k rpm in video noise loaduiest at 1.5k in video.

 

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Possibly could be timing chain or rod bearing. But it almost sounds like an exhaust manifold leak too. Check around there first before digging deeper.

Sent from Uranus with Love.
 

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This is where some sound analysis software would be helpful, and unfortunately I am not an expert in that. The two most likely causes are rod knock or lifter tick. Hard to tell from the video, but rod knock would be at the frequency of crank rotation and lifter tick at half of that frequency. If anyone can analyze the sound file then this may answer the question.
 

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IMO that is not what lifter tick sounds like. I would drain the oil, probably send a sample to Blackstone, drop the pan and see what you find.
 

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Pull the valve cover off that bank and don't start the car again. Might be a totally collapsed lifter, very rare on these cars. Could be the cam chain tensioner failed, or maybe the spring clip that holds the vanos pump in place is half off and smacking something? If you remove the cover it will probably be self evident. Running the car is just going to make things worse, so don't do that. It could also be the timing chain but they don't really sound like that, but that is videos, they change things. If you don't see anything up top drain the oil and pull the lower pan looking for plastic bits that were once the chain guides.
 

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You may want to run a compression check. Not to alarm you but I had an intake valve collision on my 01 about 2 years ago (appx the same mileage). An uncanny resemblance in terms of how I remember it sounding. Most of all, good luck. Hope it turns out to be simple.
 

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That does not sound good. Broken rocker arm?

I would NOT run the engine until you get some help on diagnosis. Right now it is still running, so damage is not excessive....YET.

Regards,
Jerry
 

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Discussion Starter #10 (Edited)
Well it looks like rod bearings, the chucks dissolve into a liquid graphite like substance when touched. Any other thoughts guys? Everything under the value cover looks normal, compression was good.
20200403_185748.jpg
 

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Sorry, I'm not tracking! :) What do you mean the chucks dissolve into liquid graphite-like substance? Trying to learn and understand! Good to see you are eliminating other areas.
 

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Discussion Starter #12
Well I tried to remove some of the chucks to inspect them. Once you start trying to touch them with a poker or screw driver they dissolve or break up and become a sparkly liquid in the surrounding oil.
 

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What is that a picture of? Can you zoom out?
 

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Discussion Starter #14
Its the bottom of the oil pan. Its merly to show the pieces in the oil. Dose anyone know if the rod bearings would be the only culprit?
 

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Have you pulled the pan and the valve covers yet?
 

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rod bearings forsure given those shavings. If you see any plastic bits that means your chain guides are gone as well. Check your camshaft for scoring once you remove the oil pan. Cross your fingers and hope for the best cause if the camshaft is damaged you need a complete bottom end rebuild or may as well get a new engine.
 

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Yah I am curious did you not drive this for awhile sitting for months. Did u check oil periodically change oil every 3500 as recommended Castrol preferably? Not good sign ticking time bomb? Not safe to drive for sure! Get it check by a Bravarian specialist.
 

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Discussion Starter #18
I guess I should have stated the obvious with the video, the car was only started to help diagnose the issue. Xrviz if you would read the thread before posting all of your questions would be answered. The car was stored for 4 months. However it did receive an oil change before being driven with Castrol. Before the car was stored it had less than 3000 miles put on it in about 12 mouths. The year before that was also about the same.
 

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Sort of strange, rod bearing don't have to give deposits you can spin a bearing and that is it. That said metal flakes are not going to dissolve when touched, nor is plastic. Did the car run fine before you stored it? When did the knock appear and how?
 

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Discussion Starter #20 (Edited)
In the first post I describe how it happen, when it happened was within a week of putting the car back on the road. The car ran flawlessly and drove home after the noise started with no noticeble difference but the new tick, it also still starts on the first click of the key. The material in the pan would best be described as lead or graphite from a pencil. Dose anyone know forsure if rod bearings produce metal shavings or are the bearings made from a softer material that could dissolve like this?
 
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