My a/c belt broke. Is it necessary to replace the tensioner, too? thanks for feedback

 

Necessary? no. Wise? yes, unless you've replaced it recently.

 

thanks for the feedback. this would be the first replacements. i have 105k miles now

 

It would be a good idea to examine each component in the serpentine belt pathway to try and learn more.

Generally, unless the belt has a huge number of miles on it or has been exposed regularly to extreme cold (-40F) or extreme heat (+125F) ambient temperatures, they don't just break. There is usually a component (bad tensioner, bad pulley, water pump starting to seize up, etc.), mis-adjustment on the belt tension or mis-alignment of a pulley that takes out a belt.

Replacement of the tensioner and idler pulleys never hurts, but they may not be the root cause of the belt breaking.

 

at 105K, I would replace both belts, both tensioners.

your car likely was never upgraded to the hydraulic tensioner for the main belt. the mechanical tensioner is still available from online BMW parts vendors, is cheaper, and will do the job just as well as the updated part.

while you have the belts off, id inspect all accessories driven by those belts. the OP is absolutely correct; make sure you don't have something putting undue stress on the belts.

good luck with your project. I just did this, along with a few other things, on my '04 530i with 99K.

 

I would recommend replacing the tensioner and idler pulley as well. The parts are really inexpensive- like less then $140, including the belt and new bolts.

This DIY should be a good guideline- it is for the N52 engine, not the M54.

Replace N52 Serpentine Belt

Do yourself a favor and remove the cooling fan and shroud from the car. The extra 15 minutes required will save you from aches and pains and lots of swearing.

 

i'd replace the tensioner and idler wheels.

i was tracking down a noise, and found the pivot on my tensioner to be binding up and stiff. it also could be why your belt broke.