Does anyone with a non S getting this noise ?

 

I haven't pushed the idea of returning the car under the Lemon Law. I'm going to give them a go at it. Three weeks without your car, though? Uggghh! If they can figure out what's up and I can keep the loaner 'till they do, I'd be a happy camper. If they can't... well, maybe that 2008 BMW 135i I'm drooling over becomes more of a realistic possiblility.

On the up side, maybe them hanging onto your car suggests they are finally trying to put their collective heads together and get this issue sorted? If dealers are beginning to acknowledge there's an issue and recognize that the chain tensioner changes nothing... maybe its a positive sign that they are working towards a permenant solution.

They're coming to pick it up? Lucky dog. My dealer is 2-hours away! I have to drive it in to them!

Might be good to clarify with them about the service loaner, though. With my dealer, they know that if I'm MINI-less, it means I'm on the motorcycle. Not fun in January, so they pretty much have one for me whenever I've come in. Most of the time you have to request one, though.

Strangely... not that I've heard here or on MINI 2. So what system in the head/cam/valve train does the S have that the Cooper does not?

 

Ok, so I picked up the car today, tensioner replaced. drove off from cold start, and the noise is gone. Just a split second of it, right at crank-over. So we'll see how this plays out. Allegedly, this repair triggered the first NA PUMA on this issue.

Full disclosure: Apology offered on lack of loaner, in fact I didn't hear wrong when I first got the car, they do have a rental program, not a loaner, but I wasn't told that when I initiated this repair. Their bad, or more specifically, the person who told me to bring the car in but told me no loaner program available. Some sort of compensation is coming my way, but unclear what it is at this point.

That's it for now.

 

So is it gone? Or did you hear it for a spit second on your very-first start-up? Can't be both.

I sincerely hope thier NA PUMA doesn't suggest the fix is replacing the chain tensioner. I've heard of about a dozen others having this done (including myself)... and every one has reported the noise comes back.

IMO the cam chain tensioner problem is a symptom of a larger issue going on in the head.

 

Gone, as in it didn't linger beyond the split second just as I hit the start button. Sounds normal to me.

 

I'll cross my fingers for you. Post again if it comes back.

 

actually the N14 engine(R56 S) has the VANOS system only on the intake side, where the N12(R56) has it on both intake and exhaust. so it has less "stuff" on the valvetrain than the non-s.

Also the N12 has Valvetronic which the N14 does not have since it has the turbo/direct injection, used to make the extra power.

So besides engine replacement, has anybody found a definitive fix for this problem. i'm really interested since we have only had one car in the shop for this noise and we really want to be able to pinpoint the problem

 

If anyone is interested in seeing exactly what we're talking about... check out these vids from various owners:

http://www.youtube.com/watch?v=jOhtSoEe6Ww

http://www.youtube.com/watch?v=eYLCm8S0mW0&feature=related

http://www.youtube.com/watch?v=7KaR3aAlmBs&feature=related

http://video.google.nl/videoplay?docid=-6013036802814745276

http://video.google.nl/videoplay?docid=4854398762084900463

http://s161.photobucket.com/albums/t210/speed3985/?action=view&current=Bonnetup.flv

http://s161.photobucket.com/albums/t210/speed3985/?action=view&current=Coldstart.flv

http://s170.photobucket.com/albums/u262/daveycMCS/?action=view&current=MOV00057.flv

http://s161.photobucket.com/albums/t210/speed3985/?action=view&current=Outsidecar.flv

The biggest thing that stikes me is that clearly I'm not the only person experiencing this issue. Every major forum has owners discussing this cold-start rattle and new posts asking about it pop up weekly. The dealers however, don't seem to be communicating to MINI about this... or if they are, MINI doesn't seem to be disseminating the information to the other service departments on what potentially is causing the problem.

Based on owner's accounts, each dealer reports that they've never heard of anything like this and they're left to figure it out on their own. So far (in the US, at least) the same parts are getting replaced and the sound just seems to come back a few months later.

I just would have assumed that there was an international database availible to all licensed MINI Service Centers that would track and document all repairs. A searchable information network that would assist in the diagnosis and repair of such issues. Someplace where a search of "cold start rattle" would turn up results and access to service information, just as if you were searching an internet forum.

 

That's exactly the sound I experienced a little over a week ago. It was fairly cold for Dallas and the car had been sitting for about 4 days w/out being started. I started it up and it made that horrible sound. I was going to bring it in on Saturday, but it hasn't made the sound since and I didn't want to be driving a loaner over the holiday, especially if there was a chance the dealer wouldn't be able to reproduce it. However, from all those videos it is obvious there is something going on here.

 

Piston slap.

 

Mine went back today. They are letting it sit outside tonight since its pretty cold here. Hopefully they will hear the sound in all its horror tomorrow. They said they were going to contact Mini to see what they know of the issue. Sounds like Mini isnt out there telling dealers about the issue yet.

 

I've heard the same sound a few times too. It seems to get bad around 2k rpm.
I "fix" it by turning off the car then starting it up again. The noise instantly goes away.
I will be taking it in to the dealer if I hear it one more time. I was thinking it may have something to do with the oil pump getting stuck or something.

 

I'm no longer saying "100% no-way" anymore on the piston slap theory... but I will say it's about 3-4 times louder than the three cases of confimed piston slap cases that I've heard in person (Chevy, GMC and a Subie)... it's also out of time, or at least inconsistant with the timing of the engine. The three other cases I've heard in person were perfectly timed to the firing/movement of that particular piston.

Also, it would seem to me that piston slap would be an easy answer from MINI. Especially if several reports that it's a "normal" condition. Maybe its because they know people like me wouldn't want to keep any car that sounded like that, even one-out-of-100 cold starts.

We'll see.

 

I just noticed the same thing, but thought it might have been a fluke. Honestly, it's so infrequent at this point that if starting the car again makes it go away, I'm not too concerned (well, not nearly as concerned as I was, at any rate).

 

The 3rd link that shows the cold/warm comparison is what has pretty much convinced me. This link at MotoringFile has a picture of the piston, which has a shallow skirt, and rings situated high on the piston... which is a design more prone to slap (MIT did a study on the issue, I'll see if I can find a link). Wife's new RAV4 (5k miles) slaps when cold, just like her previous one did.

--edit--

MIT Paper

 

Would piston slap cause loss of power ?

 

I think its solely an issue with the S...I have a non-S and last night and this morning it was in the 30s (florida haha) and and both starts no irregular noise

 

Maybe without the valvetronic the turbo is bringing such cold air that the computer reacts different to it? Idk im just making guesses but it doesnt really sound right because who makes an engine with a turbo that cannot function in the cold?

 

anyone mechanically inclined enough who has the horrible sound to try this?

One way to check for piston slap: Remove three spark plugs, leaving number one in place. Crank the engine over until you feel the resistance of number one piston coming up on compression. Crank against compression until the piston is about half way up the cylinder. Now using the fan, rock the crankshaft back and forth and listen for a metallic knocking sound. If you hear a knock, you have piston slap and the only way out is to rebuild the engine.
reference:

http://www.forengines.com/enginetips.html

 

Rebuilding or replacing the engine isn't necessary, nor will it automatically solve the problem. Toyota, for example, went through a spell of replacing short blocks because of piston slap complaints, but it rarely solved the issue completley because of the way they build the engines in the first place.

Used to be that bores and pistons were hand matched, because of wide variation in manufacturing. Better manufacturing tolerances means that they don't do that anymore. As long as the pistons and bores are within spec, which is assumed, then there's theoretically no problem. The "problem" is when the bore is at one (large) end of the tolerance range, and the piston is at the other. Exacerbating the issue is the use of forged aluminum pistons in iron sleeves. They expand and contract at different rates dependent on temperature, which is why we're seeing more complaints now that winter is here.

If you bothered with the diagnostic method forengines.com describes, and discovered you had one offending piston, you could mic the cylinder bore and replace the piston with a better fitting one. That's a lot of labor that I don't see any dealer doing for you.

The way engines are made today, piston slap is going to be with us for a long time. It's not isolated to any particular marque.

 

No. The rings are still sealing the combustion chamber.

 

This happened to me a few mornings ago when I had not driven the car for a couple of days. My car is garage kept and the temp stays around 45-50 in there even on very cold nights (teens here in GA the last few nights). Another MINI owner posted this in reply to my questioning this noise:

"Do you have a turbo? The heat shield rattles when it's cold.

Remember 6th grade science class? Cold metal shrinks. The metalurgy of your engine is superior to the sheet metal of other parts --- they take longer to heat up. Some parts sound like a bucket of bolts until they get warm."

It hasn't happened to me again and went away once I shifted to third gear and got the car warmed up the morning it did happen.

 

Sounds like the dealer checked each piston individually today. Good news and bad news. No knocks heard in any of 'em. The root cause therefore, still remains a mystery.

Several UK dealers seem to be blaming the issue on oil not entering the head and valve train and not properly operating the hydralic lifters and chain tensioner. Somthing about temps causing "frothing" in the oil circut. No reports on trying different oil, though. Wouldn't it be nice it MINI could narrow it down to somthing that simple, like the specific type of oil used? A switch to another brand, weight, or type. Somthing with a little better viscosity that warmed up a little quicker and wasn't prone to "frothing" (if that's what's really going on). One can dream.

 

Well I got my MCS back on Friday. I have not heard the sound since its return though its been unseasonably warm here (40's) for January. Its supposed to get back down in the 20's by the end of the week so I'll know for sure then.

What the dealer told me they did is first checked the manufacturing date of my chain tensioner to make sure it was "the new design", which it did. My car has a production date of 1/20/07. Then they said there was air in the timing chain tensioner which keeps the tensioner from pushing against the guide rail all the way and thus causing the noise. They simply bled the air out, and it supposed to be good to go.

Once the car warms up, the oil expands and pushes the tensioner against the rail. That's why they told me the sound goes away once the car warms up.

 

Could you clarify with your service dept:

-Did they replace your cam chain tensioner? Or just bleed out the air in the piston?

-If they just bled it out, what's to suggest it won't come back?

-So there's been a design change to the cam chain tesioner at some point? When? Do January builds already have the updated design?