Tapping Noise from Engine Compartment

[Cincinnatus]

Hope one of you folks here can point me in the right direction.

Quick backgrounder, I'm a low-mileage driver, on a seasonal basis. In the nearly 5 years I've owned the car since buying it at about 29K, I put only put only about 25k miles on the car, only about 2500 miles this past year.

Early in last season (approx. April of '21) I rolled my M6 in for an oil service, brake and coolant flush/fill and AC recharge at the 52K-ish mark. At that time, I was advised that there was a leak from the valve cover gasket that required a replacement which was performed.

Ever since then, I've been hearing a noise from the motor that ranges from a slight tapping (think: valve noise) to a slightly louder knock from the engine compartment. I rolled it back to the same service location shortly after hearing the noise for the first time, they acknowledged that there was a sound, and speculated it might be turbo bearings or wastegate rattle.

I doubt that it's a wastegate sound, can't speak to the turbo bearing possibility, but the shop said that a further diagnosis would require dropping the motor and stripping it down to identify the cause, a $20K-ish job. That sounded outrageous to me and I felt as though they were 'working me over', so I plan to get a second opinion from a different shop, just to be sure.

For the record, I have been sending my oil to Blackstone at every change (usually in the spring of each year) and it's come back with high marks each time, so there's no evidence of problematic wear indicated at present. If for example, elevated levels of copper were found, that would probably point to rod bearings. Although the S63 doesn't suffer the same reputation of the S85, such things are not out of the realm of possibility, but so far, so good where this engine is concerned.

Blackstone did say that there was a higher silica content in the oil. I asked if it might have something to do with the valve covrer gasket replacement, and they said 'yes', but did not elaborate on how or why. I'm wondering if that might suggest air filter failure, but I'm open to thoughts on that.

So the question gets down to this.

How might a valve cover gasket replacement cause such a noise in the motor? What could possibly have gone wrong in that procedure to cause that noise and what might be the long-term risk to the engine?

Thanks in advance for your input!

[TinCanSailor]

Sorry to hear about the trouble Cincinnatus

See if you can capture the sound and post it to youtube and share the link back here. I doubt it is the turbo and based on other folks experiences and along with mine Blackstone has not proven to be a very reliable source for predicting what seems to be a more frequent issue with these engines and that is rod bearings. Bent rod(s) may be the culprit or possibly a cracked piston, usually number 4 or number 8 due to the high temps experienced at the back of the engine. Some folks have had extortionary luck with their engine in terms of high miles and no issues with bearings etc whereas my car had bearings done at 50k by the dealer and then later spun a bearing at 86k. Possibly the vanos system but I have not read on here or on the M5 forum about issues/sounds from dirty vanos solenoids. Possibly the injectors as I have read they can be a bit chatty or the timing chain but at 50kish miles that would seem a little premature as I think that isn't due until 65k.

When mine at itself it was pretty hard to find information on independent engine builders so mine sat in the driveway for about 3 months while I researched the matter. I eventually found Raza who own Sales@RKautowerks out of Dallas, Tx area. They are very knowledgeable and extremely reliable as well as approachable. The reason I am name dropping before hearing the video and audio is that you may want to call and chat with Mike and/or Raza. Contact info is on the main page https://www.rkautowerks.com/

[Cincinnatus]

So you find nothing suspiciously coincidental that the noise appeared immediately after the valve cover gasket replacement? I mean, yeah. What you suggest could be a possibility, and I won't rule it out, but it just seems strange. Makes me wonder if the tech didn't knock something out of alignment or leave a pair of pliers in there when he was poking around.

[TinCanSailor]

The VANOS solenoids use oil to control valve timing. Inside the there is a screen on the VANOS to sort of debris in the oil so there is a chance that they introduced something that made it to the solenoid but the same cold be said about the metal that gets liberated from the rod bearings or shavings from a bent rod knocking around. They would have to remove the injectors as part of the procedure and may have replaced them in the wrong order. Each injector has a calibration code that is coded in the dme per cylinder. If you have bimmerlink try to pull some codes and grab a sound clip of the engine. You can also buy a Mechanic's Stethoscope to try to narrow down where the sound is emanating from.

[Cincinnatus]

Originally Posted by TinCanSailor

The VANOS solenoids use oil to control valve timing. Inside the there is a screen on the VANOS to sort of debris in the oil so there is a chance that they introduced something that made it to the solenoid but the same cold be said about the metal that gets liberated from the rod bearings or shavings from a bent rod knocking around. They would have to remove the injectors as part of the procedure and may have replaced them in the wrong order. Each injector has a calibration code that is coded in the dme per cylinder. If you have bimmerlink try to pull some codes and grab a sound clip of the engine. You can also buy a Mechanic's Stethoscope to try to narrow down where the sound is emanating from.

You've definitely given me some things to think about. I have a Carly dongle, would that do the trick to pull codes or is Bimmercode the better way to go?

[TinCanSailor]

I haven't used carly but have heard very positive reviews. Keep us posted.

[Qsilver7]

Originally Posted by Cincinnatus

You've definitely given me some things to think about. I have a Carly dongle, would that do the trick to pull codes or is Bimmercode the better way to go?

Bimmercode does not pull codes…it is specifically a coding app only. Their sister app…BIMMERLINK is their diagnostic app.

[Cincinnatus]

Originally Posted by TinCanSailor

I haven't used carly but have heard very positive reviews. Keep us posted.

Just used Carly to pull codes. Here's what I've got:
213601 (power management)
190302 (tank venting)
190303 (tank venting - purge air micro leak greater than 0.5mm)
INFO 1FB101 (power management upper threshold undershot)
INFO 118010 (mixture control / too lean)
INFO 11CF30 (Mixture ECU: group error)

I'm guessing most of these are because the car sat for some time without being started and I've only put 2200 miles on it this season since the noise started after the valve cover gasket repair.

Any insights are appreciated.

Thanks in advance!