the serpentine belt snapped off while i was casually driving to the corner store last night, luckily i was only a block away so i drove back home right away and turned off the car rolling.

i looked under the hood and bam! not only my belt was missing but the hydraulic tensioner snapped in half, the little arm that is attached to the hydraulic tensioner apperead to be grinding on the crankshaft pulley from all the metal shavings as well which is also freaking me out.

but my question is why did it snap off and cause the hydraulic tensioner to break? i recently changed out the serpentine belt but little did i know that the stock oem belt was to be used with the upgraded 15% pulley from ALTA, instead of the actual 15% designed aftermarket belt. could this have been the problem? did i install the belt wrong and have the belt grind outside of the ribs???!!

 

Not sure about upgraded pulley and different sized belts but is it possible it happened the other way around and your tensioner broke taking your belt with it? You didn't mention you found the belt.

I think it might help others to know the size/specs of the belt and when you had installed it.

 

Not sure about upgraded pulley and different sized belts but is it possible it happened the other way around and your tensioner broke taking your belt with it? You didn't mention you found the belt.

I think it might help others to know the size/specs of the belt and when you had installed it.

 

Crazyworld is right. The tensioner broke, it wasn't the belt's fault. They are prone to that. If you retrace your steps and find the belt, more likely than not it will be in one piece if it didn't get shredded when the tensioner went.

 

A loose or worn belt....especially with a weak tensioner can jump....destroying the tensioner and hitting the crank damper....destroying it....
That is why MANY folks use a tensioner stop of some type on a gen1 car....so if the belt brakes...it SHOULD stop the carnage.....
A new belt YEARLY WITH A 17%...or every 2 with a 15% IMO us a good idea.... And a properly sized one too!! Early on folks did use OEM or JCW belts with pullies...but better options are around now....

 

Tensioner stops, don't get me started. Bottom line is they aren't worth your money.

 

What problems do you see with tensioner stops?

 

The tensioner stop will fall off, or fail, well before the tensioner, basically making it a worthless part. Replace your belts routinely on schedule, and check the tensioner. Don't rely on the tensioner stop to "save the day." It won't. Routine maintenance will.

 

A stop is kinda like an EXTRA step... Not perfect...heck...there are some cheap knockoffs out there using aluminum electrical eyelets on the end of a cable.... Those WILL FAIL...the early ones from DT TUNED is still on my car...has not worn/failed...Using the stop is kinda like wearing a belt AND suspenders....nothing beats regular belt changes..but if the belt jumps...a $20 part MIGHT save you $600+. Not 100% in all cases as folks have found...but if it works...cheap insurance!!
Heck the most likely time for a belt to fail for many is RIGHT AFTER A MOD...like above...if the tensioner had been installed....and let's say it worked for 3 months...would have save the op 600+$ (plus install and downtime)....
Getting the belt size and alignment right is an issue for some...the tensioner can be a big $$ saver!! But it is NO SUBUSTUTE FOR REGULAR MX!!

 

It's only going to help if everything, including the tabs, break. It wouldn't have helped the original poster one bit.

And just because the tensioner goes doesn't mean impending doom, as long as you use common sense. It's literally a dollar part to manufacture. If the tensioner stop was so critical, at so cheap a price, BMW would have put it there in the first place, or at some point during the R53 refreshes. They didn't.

Bottom line still holds. You're tensioner stop will go before you tensioner.

Call Helix, ask them why they don't sell them.

But to each their own; there are far more expensive things to waste your money on a MINI, and I've been guilty of that myself.