2011 Base Coupe. As I mentioned, I literally just rolled over 100k today, on my way home from work. I am sitting at about 100,008 miles. I am second owner, first owner had records of all, on time services, always used full synthetic. I continued on properly - almost obsessively. It is my daily driver, but my commute is smooth highway, about 20 miles one way. I drive another vehicle around town and on the weekends. I only use full synthetic. I have also changed the oil every 6 months because 15k miles is just too much for me, though I am sure it is fine, just not a problem for me to do it every 6 months. I have always checked the oil level when I get gas..literally every single time I have gotten gas since I have owned it for the past 2 years. I would need to put in about 1/5 a quart every month to month and a half. No leaks, literally NO problems whatsoever with this car. (Not even the timing chain guide issue)

Then today...when I get off the highway, I get to the only stop light before my house and I heard it. I thought, surely it couldn't be. It was not doing this when I left work 20 minutes prior. I absolutely would have noticed it. When in the car, I only hear it at idle because it gets drowned out by the engine noise. It is running/driving fine by the way.

I pulled into the gas station to check it out, which is when I took the first video below. Then, I drove about 2 miles home which was in town. Then I took the second video which is where you can really hear it. I haven't pulled out the scope or done any actual diagnosing, but fairly certain that it is #1 cylinder. I do have a CEL P0597 for the thermostat being stuck open. I have the replacement stat but haven't replaced it yet because it has been cold/winter/rainy forever here and I don't have a garage. I also noticed about a month back that it was about 3/4 quart low on coolant. I noticed this because my heat wasn't working at idle. However, I clearly don't think this has anything to do with it.

I'm so pissed and have no freaking clue how this would happen considering I literally did everything to avoid this very problem. I am DIY till I die and have been working on cars since I was a mid-teen (read: basically broke and can't just take it to mechanic to get it fixed). Interestingly enough, I have done just about everything on a vehicle except ever had to deal with this issue. I have seen it done plenty, just never done it myself.

Any ideas here? I am guessing you will probably say I am correct in my assumption (barring actual diagnosis) but I sure wish it could possibly be something else I should check.

EDIT: So I have been looking around on the forums and YouTube and such and, maybe I am just wishful thinking here, but could this possibly be the friction pulley that engages the water pump? I have seen references to it sounding exactly like the rod bearing on that same side.

Grab the popcorn...

 

I do have new video with more detail that I will try to post this evening. However, as an update, I did a few things regarding diagnosing where this is coming from.

I revved it much higher, about 3000-3500 and it does seem to go away and them come back as the RPMs wind down. I pulled each plug, one at a time, as I would expect to hear the knock either go away or at least change/get quieter if it was rod knock (or anything in the cylinder really, wrist pin, piston slap, etc.). There is no difference in the knock whatsoever. (Hopefully a good sign).

I took the oil filter cap off to take a sample of oil and look at the filter to see if I saw any of the "death glitter" of metal shavings. It was totally clean, not a single fleck.

I used a mech. scope to listen. I could heard the knock at each of the cylinders, but it was definitely a referred sound, and fairly quiet. However, when I put the scope on one of the water pump bolts, it was absolutely louder. Tomorrow I plan on removing the tire and fender well cover to check out the pulleys and crankshaft, etc.

Also noticed it does sound a little higher up than where the crankshaft is. Also noticed it is not quite the sound of a spun bearing. The metal on metal isn't there like I have heard with other rod knock.

Waiting on a spark plug socket I had to special order that will be here tomorrow and I will test for piston movement. I am a little more hopeful that it isn't rod knock now. However, still not sure what it is. I suppose it could be timing, but it isn't rattle at all. That is a fairly classic sound and I am just not hearing it. I will post the other videos from yesterday this evening hopefully.

 

Have you ever replaced the timing chain tensioner? Particularly with 100k miles, it's entirely possible the tensioner, which is hydraulic, has collapsed and is no longer putting pressure on the timing chain guide (therefore loosening the chain). That would create noise at idle but the noise would dissipate at higher RPMs due to centrifugal force on the chain.

 

Brother, if that's all it is, I'd be a happy camper .It is certainly a possibility . As far as I know, it has never been changed .I never changed it and don't think the PO did either. I don't see it in the service records. Is there a good way to test the tensioner before I just throw a part at it?

 

You can find a Febi/Bilstein tensioner on partsgeek.com for $30. It's a PITA to get to but given the mileage of your car, it's a logical first step. If it doesn't eliminate the noise, you at least have a new tensioner (needs replacing anyway) and are further down the road to a solution without sinking a ton of money into it. You might also use your scope and place the tip on the timing chain cover to try and isolate the sound. Another thought is that you could have compromised (think broken) timing chain guide(s) in which case you would more than likely find pieces of it/them in your oil pan.

 

Ha, just saw you were in DFW - my oldest son is in the Air Force and he and his wife live in Fort Worth.

Anyway, so is the Febi-Bilstein as good as the MINI OEM? Also, which length should I get? Part of me is tempted..since I am already going to be working on it, should I just replace the chain and guides while I am at it and get the cam locking tool set. Maybe not. I am not sure that is needed. I have the Bentley, just got it today actually, but haven't dug in too much yet - is changing the timing chain a maintenance item? I suppose it is, don't want to wait till it breaks loose. If so, I may just bite the bullet and go ahead and do it all. I do have a base and a 2011, so the timing chain/guides issues aren't as big of an issue, but still may make sense.
Haven't decided for sure yet. I have just read around that a new tensioner could possible jack up the old chain and guides eventually if you don't change those as well.

 

Febi/Bilstein is a German OEM supplier for MINI -- my shocks are Bilstein B4s, for instance. You can certainly pay more but I'm not sure you're going to receive additional value for such an uncomplicated part. Your R56 tensioner is different than my R53 so you'll have to do a bit of research to ID the correct part. If it was me, I'd start with just replacing the tensioner, then move to the guides, chain, etc. if required - a little triage so to speak. I play the old Carswell AFB golf course from time to time -- fun course.