Today the serpentine belt broke on my MCS '04 (while driving to work). After that happened I heard a tapping sound on the engine so i turn it off and called for road assistant. I took it to the dealership for service and they told me that the harmonic balancer and belt tensioner were damaged and needed to be replaced because of the broken belt. They blamed the reduction pulley i have installed on the car and didn't wanted to give me warraty service for that.
Do you guys think this is possible (Harmonic Balancer and Belt tensioner damaged becaused of a broken belt)????

 

I can see the possibility of the tensioner being damaged but, it would be tuff to damage the harmonic balancer. How many miles since you installed the pulley and what brand pulley was it?

 

We just got a Customer's car back from Watkins Glen that did the same thing. This was his umpteenth track day this year, and his belt gave up--probably due to the faulty dampener (the little black shock absorber on the tensioner bracket).

I am seeing more and more of the dampener failures, and one of my MINI dealer tech buddies says that he's replacing alot of tensioners under warranty. You can tell if your dampener is really bad by running the motor at idle and looking at your tensioner pulley. That's the one that is just below the supercharger pulley, attached to the metal bracket with the spring on it. if it is dancing back and fourth under the spring tension, your dampener is faulty. This can heat up your belt and cause it to fail. Another common failure is the tensioner or idler pulley bearings which can also cause your belt to fail. If you need help identifying these, you can call me and I'll describe it.

These belt failure causes are happening on stock cars, and are not the fault of the smaller pulley. If you dealer refuses service, ask to see the broken parts and check for bad bearings in the pulleys, as well as that dampener. Again, I'd be happy to describe to you what to look for.

When the tensioner bracket breaks, the tensioner spring forces the broken piece of aluminum bracket into the crank pulley (harmonic balancer). both parts do a pretty good job of machining each other. So I think that your dealership is correct about needing a new crank pulley.

In my opinion, it is likely that your belt failure was the effect of one of three things: bad tensioner pulley, dampener, or idler pulley. Of course they will try to avoid the warranty work, but if you go armed with some information and a bad attitude, you have a good shot at prevailing.

 

Yeap i went to see the car today and is exactly what you said Helix13mini.... The tensioner bracket broke making the aluminum bracket rest into the crank pulley (harmonic balancer). I told them that it has nothing to do with the reduction pulley but they didnt hear me. I commented about the warranty again and they didn't wanted to do it under warranty service... So I bought the parts and took the car out of the dealer. i'm going to do the job next week...

Thanks for the info guys.. have a good day....

 

Gclass, Sorry for the problems and warranty denial- What parts did you buy and what was the cost? I'm wondering if i should do some PM and just purchase the tensioner, balancer, pulley.

 

Note that BBM offers a tougher tensioner as part of their pulley upgrade kit. Wonder if they'd sell just the tensioner?

The stock piece looks like a POS, and where one will fail, so will another.

Jeff

 

I wish BBM would supply more info on their tensioner....pictures...something.

 

i found a BBM that was only vw parts. can you tell me where to find the BBM you are refering to?

 

A P&D solution to this issue. < Helix13mini, you would be the only shop in the States offering a fix.
Bisch, BBR sells the idler pulley to DIYers for 195 pounds.
You know the first thing I did after reading this thread was go out and check mine!

 

Wouldn't a reduced size pulley, put less pressure on a tensioner? Sorry the dealer used a way out.

 

Less warranty pressure on the dealer, yes.

 

Is there a correlation between the issues noted here and the problem associated with the thread below (harmonic balancer issues leading to clattering noises under acceleration)??

https://www.northamericanmotoring.co...ad.php?t=18230


I've had my MCS to the dealer 4 times to look at this issue over the past 10K miles. I continue to receive the following response "we've never had to do any warranty work to resolve this type of issue on a MINI; it's pretty common, don't worry about it." Obviously, this is a brush off, any further help in leveraging attention on this issue is appreciated!

 

BBr sells an upgraded idler pulley assembly, and they are adamant that this is a weak point on the system. I raised this concern before on this board, but not a lot of response. It it interesting seeing the problem arise.

If we are starting to see more and more of these, is it because more and more miles are being put on cars with the pulleys? In the beginning (early to mid 2003) only a few cars had pulley and not a lot of miles were put on them. As more and more cars get them, and the cars are working harder (more people taking them to the track), and more miles are being put on the car, could this problem now be appearing. How many is this happening to with pulleys and without pulleys?

Anyway, some interesting stuff. Gclass, who installed your pulley? If you bought it from Randy, I know that he will offer some assistance in working with the dealer. Also, how can the dealer refuse the warranty work. Was the pulley installed incorrectly? If not, did they explain, what did the pulley specifically do to cause the failure. The responsibility on them is to prove the aftermarket part caused the problem, not on you. The JCW kit that they sell contains a reduction pulley as well.

 

Well I'm using an Alta 15% reduction pulley, and I got it installed by one the mini technician here in Puerto Rico. Apparently the belt we used (JCW belt) was not the correct one when using 15% reduction making the belt tensioner to fail, so I order the belt from Minimania and the Harmonic Balancer, tensioner and idler pulley from Classic Auto Campus. Right now we are waiting to get the parts and install them this week.

 

I just installed a 15% yesterday and I have been watching the pulley area closely (I never really looked in the area before). I have noticed that the tensioner pulley does dance a little bit. Not a substantial amount, but some.

Would it be wise to go ahead and replace the damper now?

BTW - I only have 3300 miles on my '04.

 

If the tensioner pulley is moving three millimeters or less, don't worry about it. If it's more than that I'd say get it done. With that milage, though, you should be fine.

Whoever installed your pulley should have checked it before delivering your car.

 

I had an issue because my idler was bad, is was making a rattliing noise from the little tab that is used when changing the belt. I then had to replace the crank pulley (harmonic balencer) because my dealer bent it..... though they did not fess up until I had a large argument with them. Eric was there when I noticed the pulley. Was not a good thing... the belt was starting to shread to pieces.

 

I installed the pulley. I did not notice how much it moved in stock form. It may have been the same as now.

The tensioner moves just a tiny bit - I'll inspect again and check a stocker tonight at our club meeting. It doesn't look like anything to worry about - but if I can prevent future damage, I will.

Thank you.

 

Norm - Funny, I was thinking about the same thing the other day after Eric's client suffered the tensioner failure.

Time for some more jlm design genius.

 

I think that the tensioner failures are not necessarily indicative of the tensioner being the weak point, but rather that it breaks when one of several other weak points fail. Specifically, as I said, the tensioner dampener, the idler pulley, or the tensioner pulley. My guess is that the tensioner arms snaps when the belt breaks, (the belt) having been heated up due to one of the above failures.

The idea of a heartier tensioner assembly does sound tasty, but if the above is right, it would be a clumsy engineering solution: a bigger band aid does not prevent the wound.

The problem is identifying these trouble spots before you are calling roadside assistance. The best you can do right now is to observe tensioner movement, and also the relative shinyness of the back of the belt. If it is unusually shiny--I mean really shiny and smooth, it may be rubbing on a reluctant idler pulley, and it's time to go to your dealership, or better yet roll into Helix.

Pilo: the idler pulley is the one next to the AC compressor, not the one with the tab. That's the tensioner pulley: you may remember how it was arranged from when I installed your pulley for you, and pointed out your damaged harmonic balancer.

 

Sounds like you are suffering the failure that some of us have been able to avoid, so far, by having Mini replace the Harmonic Dampner. It's a long thread but check this out:

https://www.northamericanmotoring.co...ad.php?t=18230

 

ok so i just dropped my car off today with the same problem. What was the price you guys paid for this to fix?

 

You've got THAT RIGHT!!!! I've just been noticing tonight that there was a 'new sound' at idle. I LOVE the performance/sound of my car and I LISTEN to it. Anyway, I popped the bonnet and looked for the source of the rattle. Sure enough, the Tensioner is litterally dancing and bouncing on the belt. I'm going to park it and get a new tensioner assembly. Can I just say, this site and my fellow MINI drivers absolutely ROCK. Thanks!! ~jon

 

Make sure you order the tensioner stop cable also. Detroit tuned hooked me up with both for a good price.
-J

p.s. check your the rubber in your harmonic balancer while your in there. If there is any cracking get a new one or alta one piece crank pulley like i did.

 

I was thinking the same thing. About a month ago, I had the M7 +2% and -16% pulleys installed. I had debated on the +2% until my mechanic inspected the stock crank pulley/harmonic balancer and observed the same rubber degradation. I'd hate to ruin the new JCW belt and Pulley at the same time . Right now, I'm scared to drive the thing around the block BUT, Hurricane Gustav is breathing down my neck and I don't have off-street parking...in other words, even though I KNOW the tensioner is going out, I NEED to move the car to a safe location, ie. a carport/garage. I'm sort of in a bind...wish me luck.