Well, looks like I'm another victim to the diesel clatter...3500 miles here...

Started the car last week Thursday after it sitting for a few days, heard the clatter, thought something was seriously wrong. I opened up the bonnet and heard the g-d awful sound, something like what an engine with bad lifters would sound like...I listened as the car was idling high for a good 2-3 minutes until the noise just disappeared.

This morning I got in my car (after it sitting for a few days again) and heard the clatter again, but was in a little rush so I starting moving almost immediately. The clatter remained while driving for a minute or so and then just disappeared. Tonight I jumped into my car again (it was sitting for probably 10 hours w/o being driven) and I heard the clatter again, but only for about 30 seconds or so.

Granted the last few days have been colder than normal, and this is the first time my Mini has experienced these temps since I got it in June this year (40-50 degrees), but that noise is so wrong in so many ways. Not cool.

 

Aw crap ... 9 months and 3500 miles after receiving the "full monty" SIM-11-02-07 repair, my '07 MCS has started doing the cold start chain rattle again. So far, only two occasions, both first start of the day. 32,000 miles total.

Called the MINI SA and requested my comments be entered into the car's file. She said that they have not had any "come-backs" with the SIM repair - I'd be the first. Since it's not consistant or predicatable yet, I'm going to hold off bringing it in until there's a reasonable chance they can replicate the rattle.

Oregon lemon law requires 3 attempts to fix a problem. MINI has repaired the car twice, so guess I'm going to have to do the 200 mile pilgramage once again ...

 

Maybe it would be good to start a Cold Start Clatter Recurrence thread? It would be helpful to get an idea of how many people have the problem come back.

 

Well, you've described the classic timing chain tensioner failure to a "T". As has been aptly demonstrated now by hundreds (thousands ?) of MCS owners, when you're hearing the engine rattle, the timing chain is busy tearing up the guides, rails, and sprockets.

You've got a new car. I've got the latest tensioner repair (SIM-11-02-7), and both still have defective chain tensioners. How difficult can it be to design and install a chain tensioner that works at startup? Ever heard an American or Japanese engine with a defective tensioner? I haven't.

It appears that BMW's latest fix didn't work - again.

 

You didn't read my post on the previous page. Here is a tidbit from a web page on oil change intervals. Saturn is (or was) an American car.
Source: http://www.nordicgroup.us/oil.htm#Oi...ge%20Intervals

 

I just spend a while on a saturn site, http://www.saturnfans.com, and the consensus there is that problems with the S series engines has more to do with letting the level get too low during extended oil change intervals, not a glazing that builds up that is taken care of by more frequent oil change intervals. There are several posters who have half million mile cars with extended change intervals even using convetional oils.

For the scenario of the varnish to be accurate, then the oils would have to have significant degredation in detergent levels and additive break-down over the 3k to 5k mileage interval, and with the more modern engine oils, this doesn't seem to be the case.

I'm not saying the guy is wrong, but he's saying a very unique viewpoint I haven't seen referenced any where else.

Matt

 

From what little knowledge I have, it seems that this problem may not be well understood anywhere. MINI doesn't seem to have solved it, or people wouldn't be having the problem recur. The rumors have been: air in the system, insufficient oiling, varnish...

 

, Metroplex Minis, I think, some one who works in valvetrain desing seems to have it nailed down to too much range in the hydraulic lash adjusters. Fix would involve R/R any damanged parts, and new redesigned rocker arms. Best root cause analysis I've seen anywhere. I really can't believe that BMW/Mini hasn't read the work, as it's referenced several places. But instead they seem to keep chasing what looks to be at best improvements to the symptoms, as opposed to the root cause.

Anyway, the theory is that the poor lash adjusters let the rockers hit the cam too hard, this in turn gets translated into force impulses on the valve train and cam chain. This is what causes everything to break.

Matt

 

Yup. Most credible theory yet. the irony here is that the SAE engineer who came up with the Hydraulic Lash Adjuster aeration due-to-loss-of-oil theory as the culprit, his company supplied valve train parts to Chrysler/BMW for the beloved Tritec used in the first gen cars. And BMW continues to blow him off.

That's their problem. all I know is this: despite knocking pretty hard on me twice in my car's first 3k miles, once I started to bump the engine to 3K or so, then shut off power (if the car was going to parked 6+hours or nose-down) the problem has not recurred since then (7 mos, 5K miles ago) even on the coldest of mornings. The thoery is that the rush of oil to the HLAs during rev up/shut off is keeping them from aereating, which produces the pnuematic-ish cold start noise upon restart of a dead-cold engine. I aint no SAE tech-head, but it seems obvious.

I encourage everyone with the knock to give it a try. Bump, hold for a sec, then shut down. Very simple.

 

Is there a graphic somewhere of this area? It has been decades, but the last dual-overhead cam engine I saw didn't have rocker arms. So, I can't quite visualize this.

 

Do you let it drop to idle before you hit the Start/Stop button? Or, hit the button while it is at 3K rpm?

 

#4 is the rocker arm. Not the same as on your normal OHV engine, but it fulcrums on a pivot with a roller that rides on the cam and the tip actuates the valve. Mini calles it a "roller drag link", FWIW....

If REALOEM blocks the graphic (sometimes they do that) here's the link. But I know what you're saying... My FIAT had cams that pushed straight onto a "lifter" that was just sitting on top of the valve tip. Solid lifter, no arm set-up. I think modern engines use stuff like this to get a roller to ride the cam and some mechanical amplification of the cam profile.

Matt

 

I believe the technique is to hit the stop button while the engine is turning at 3K.

I suggested to sequence almost a year ago that he trademark his rattle-mitigating R56 shut-down procedure.

 

Yes Gil and RC that is correct: rev to 3K, hold for a sec, hit the stop button. I asked my SA and he says there is no harm in doing so, and if it works, take it to the bank.

 

robin, no to the first ?, yes to the 2nd. As much as Gil is my champion, I admit I cant take credit for this, yet I cant remember where I read about it. I think it was someone that has an old V8 GM product with HLAs, and he has to do it every time he parks long enuf to let the engine go cold, or the big-time valve lash banging happens the next time he fires it up.

 

Thanks.

If I do something like this with my Acura, it wont start. Not sure why, but I'll have to adapt to different routines with the two cars.

 

Well I had the lastest SIM proceedure back in the spring and now that cold weather has rolled into Chicago... ta-dah the rattle is back... (yes I know it is cold engine and not cold weather)

What worries me the most is that it seems to be more frequent now and maybe even louder than it has been in the past. When it was in the for SIM my chain was within spec so only the tensioner was changed - maybe time to re-measure?

 

There's a number of posts on other forums by owners with the exact situation you're in. They took the car back in, and received the "full monty" SIM-11-02-07 after a repeat chain deflection test now measured beyond the limit. Seems to be 50/50 whether the techs are required to verify again they heard the rattle on a cold start. Some dealers are going with a "We heard it once, that's good enough" philosophy, others aren't.

 

I had the same problem recently and decided to take my MINI in yesterday. The dealer has been receiving a few MINIs with this same problem and told me that they know exactly what do do. Will pick up my car tomorrow! Will update for the fellow MINI drivers. You guys can find more info about this "Cold Start Issue" at the link below. I would recommend everyone has his problem check at local dealers. It's Free of Charge!

http://www.motoringfile.com/2009/05/...d-start-issue/

P.S. GOOD LUCK GUYS!

 

Had the tensioner replaced on my 07 MCSa last week (the chain was within spec). My S.A. did not have to verify the chatter... so far no chatter on start-up. Also had a rattle in my center dash area and a buzz in my tach fixed.

 

Do you know what they did to cure the tach rattle? I've got two '07 MCSs and they both have an annoying dash rattle centered on the tach area when driving on rough asphalt

 

I brought my 07 s in to the dealer in 5/'08 and 5/'09 to try to fix the cold start rattle. 1st attempt was to bleed oil from engine oil. 2nd attempt was replacing the timing chain tensioner per SIB #11-02-07. The noise is now louder than ever so now I am wondering what else can be done to fix.

 

I suspect they will replace the entire timing tensioner assembly and install a new timing chain...

Just a guess...

 

I'll let everyone know what happens after the service but Mini said just now that there is an additional fix for cars like mine.

 

They removed the dash and insulated all the contact points as per SIM 51-08-07. They also removed the alarm light cover from the tach housing and insulated the area. Rattles are now gone. The shop manager was aware of the problems and knew exactly what to do.