I just bought my 07 Mini Cooper S. The car was is a Lemon Law buy back. I was bought back from BMW due to the timing chain/cold weather rattle issue.

The car was fixed by BMW and I bought it with 37.000 miles on it. What is the best way to prevent the timing belt to fail again? Since what causes the timing belt to stretch is the failure of the tensioneer has anybody been changing it to a new one once a year or after so many miles?

I love the car so far and I will do everything I can to keep it in good shape.

 

Don't drive it... Too many variables, some have had no issues and some do, who knows what's going on. Just enjoy the ride.

 

BAHAHAHAHAHA

 

Don't let your oil level get low. That won't really prevent it, but it seems a low oil level aggravates/accelerates any problems. Even that is not foolproof though as there are plenty of examples of failures despite efforts by owners to maintain the proper oil level.

 

Wear causes it to to lengthen. ...so don't drive it!! Now, if you want to drive it, keep the oil FULL....good oil from the mini recommended list. ...change it often...and listen tor rattle. ...chewper to fix BEFORE IT FAILS...it it goes....big $$$....think motor.

 

Proper oil level and regular oil changes.

 

First, it's a timing chain, not a belt.

Second, it's not the chain that fails, it was the tensioner. That allows the chain to flp about and cause havoc. The part has been updated by BMW/MINI at least twice. The newest version should prove the fix.

There is no need to proactively change the part. If you have the newest part, (Probably sometime in 2010), it should be fine.

As others have said, Check the oil often... Slightly too much is way better than too little...

 

The plastic guide rails are also potential problems, though it could be argued that they only break when a loose chain flops around too much.

 

Trade in the R56 and buy an R53, that will fix the problem. My timing chain jumped at 62k miles, traded in the car because it wasn't worth fixing.

 

'07 here.

- Some say the 0-40 Mobil 1 Euro blend helps.
- As my chain was stretching back before BMW/MINI knew what was happening, I could make my MINI rattle by letting it cool down (like washing it), then starting it and moving it into the garage. The next morning it would always rattle. I'd say NEVER run it for 30-60 seconds and then let it sit.
- ALWAYS let the car warm up to operating temps before bringing the revs up very high.
- Kissing the key fob before starting can't hurt either.

PS. It is my understanding that it is a cold engine (room temperature not necessarily cold weather) and the resulting lack lubrication that causes the problems. Not sure, but there might be a lack of hydraulic pressure in the tensioner too.

 

Yup, three fold issue.

Low oil pressure from poor quality oil... (Because of length of time left in engine).. It gets thick... Flows too slowly to the hydro tensioner. Chain slack smacks the brittle plastic guide.

The quality of the guide plastic... Which responds poorly to poor oil conditions.

The length of the oil change interval.. Too long.. Neglected..

IMHO.

 

I've been following trying to follow the myriad discussions of the timing chain, but I have one question for those more knowledgable:

Is there a reason why the guide rails NEED to be plastic? By which I mean, is the a reason why some vendor wouldn't create a complete timing replacement kit with an upgraded tensioner and metal guide rails? Would more robust guide rails improve the overall reliability of the system?

 

It's too long, a metal slide against a metal chain would last an hour, if that The friction and pressure is just too much.

Picture a bike chain being pressed against a two foot long chunk of material as it slid over it at a high rate of speed.

Modern plastics are pretty amazing. Modern timing chain guides (plastic) are used by many manufactures without issues.. But nothing lasts forever.

I really feel the issue is oil quality/pressure. Once the chain slacks, they beat the **** out of the plastic and it accelerates the wear.

That or it's just a quality of materials issue. (The guides)..

 

Another factor that may be contributing...

These engines have many accessories on the cam shafts. Fuel pump, vacuum pump, VANOS actuators and the valve lift mechanism.

While fatigue will stretch a metal part over time, excessive load will for sure do the damage we are seeing.

It has been noted on another thread that the N14 shares the same chain as the BMW inline 6 (if my memory serves me well) and that engine doesn't seem to share the same problems as the N14... A less loaded cam system or perhaps as mentioned, the guides, tensioner and oil quality are the only factors.

The N18 engine has a different part number for the chain, and the guides are different too - a redesign happened in there somewhere. I hope they sorted it out - time will tell!

My 2 bits...
E

 

Just a correction: The original N14 timing chain was unique to the MINI/Peugeot engine. That part number was superseded lately, after 2010 by an older part number used by BMW i6 engines. Although both should be geometrically identical, the BMW chain is twice as expensive than the original MINI one. That lead me to conclude that the chain must also be more robust. I am of the belief that if you change the chain to the common BMW PN you will no longer have problems.

Problem is, the TSB BMW issued for this particular issue still makes reference to the original timing chain PN. So a lot of cars serviced for this particular issue must have gotten the same problematic chain. The PNs I am talking about are 11317534784 for the MINI and 11317516088 for the BMW.

Some online part sites list both PNs, some only the latter.

Anyway, from my understanding, the problem child is the chain, not the tensioners, at least not directly. There is a common misconception that the MINI tensioner is oil-driven, but it is not. It is a mechanical tensioner with hydraulic dampening! It has a spring inside, and it is that spring that delivers the pressure. There are tensioners that are hydraulically-driven, but they are very different to the MINI's. That is exactly why, MINI says you need to bleed the tensioner if it is to be reused (remove all oil from inside). And you don't fill a new tensioner with oil, as you do on hydraulic-driven ones.

 

Interesting.

I wonder if there is some type of alloy-coating on the updated chain.. Or or does not stretch.. (or rather.. the link pins dont wear out..).

 

I went at the IWIS website and made some research in their automotive aftermarket catalogue. IWIS is the original manufacturer of the timing chain (JWIS) for the BMW/MINI.

I compared the two part numbers and this is what I found out:
-The two chains have the same number of elements (144) and similar pitch and width (8mm x 3/16'') dimensions.
-The difference is in the pin diameter: the MINI version is actually thicker (3,31mm vs. 3,15mm)
-Despite of that, they are both rated for the same exact load: 8500N.

Judging from these findings, I tend to believe that the BMW chain uses a more expensive material for the pins to achieve the same ratings with 10% less pin area. Perhaps at some point they figured out using more of the cheaper material was better, as the BMW chain is older than the MINI's.

 

my personal theory of timing chain failure ... i have no physical evidence, only my experience as a professional aviation/auto/motorcycle mechanic and my friends similar experience

i have a friend that owns an independant auto repair shop

he tells me that he can group his mini customers into 2 groups, those that have/will have timing chain problems and those who will not

he has done many (~100) timing chain replacements and says in every case he has found the oil galley that feeds the chain tensioner partially blocked with oil sludge

these same customers had done only the OBC directed oil/filter changes

the second group (no timing chain issues) do 3,000 - 5,000 mile oil/filter changes

my friend now INSISTS that all his customers with minis change the oil/filter at a maximum of 5,000 miles

secondary evidence is mini reducing the oil/filter change interval from 15K to 10K and now 8K miles

i do not want to be flooded with "i had my oil tested and it was fine" posts ... THERE IS NO TEST FOR SLUDGING, the oil tests are for the lubricating properties and contamination of the oil

i see this all the time in aviation, customers insist on oil testing and extended change intervals based on the results ... the end result is sludge buildup and when we show the customer, we go back to normal oil change intervals

scott

 

Oil can be a problem, but in the opposite way most people think. The tensioner itself cannot be controlled with oil-pressure as it only has a very small entrance/exit point at its tip. Whatever oil gets inside, looses pressure during entrance. Oil pressure in the tensioner builds up as the tensioner is compressed (irrespectrive of the main oil supply), as it tries to exit from the tiny hole on the tip.

What happens here, is that as the oil cools (engine not running) it also thickens. When you press the tensioner in this condition, it will feel harder. The problem begins when it needs to extend, as the thickened oil makes it slower effectively reducing tension in the chain. This behaviour correlates perfectly to the temperature observations: hot weather or engine no prob, cold weather more time for the rattle to stop. I don't think that oil pressure is the issue here. And because of the design, when changing oil, old oil will remain in the tensioner. The car would need to be driven hard to compress the tensioner and release the oil trapped within.

Perhaps it would be wise, to remove the tensioner at each oil change and drain it as per BMW instructions.

 

Wish it was that simple but I have always changed my oil every 4,000 miles using Mini oil and filter. My timing chain and associated parts had to be replaced at 24K miles.

 

Check this out...

http://www.motoringfile.com/2013/05/...er/#more-29526

 

I had mine changed to the latest one less than a week ago and the problem is back
Not just the timing chain was changed, but everything else - tensioner, rails, guides etc

 

Don't know if it's related, but my warranty is probably going to replace the whole assembly even though by specs, I only need the tensioner. The warranty agent said that it was because of a bulletin from mini, not sure if it was a new one. Waiting to find out for sure in the morning.

 

So much for the oil theory

 

What oil theory