1.6 tdi alternator belt tensioner bolt snapped

Recently the aircon pump and dryer was replaced on my sisters 09 1.6 tdi golf.While she was driving the car yesterday she lost her aircon and the charge light came on.I removed the covers underneath to find the pully which tensions the belt lying on the plastic tray along with the bolt that tensions it snapped in half.Its not spring loaded and is just tightened up via the bolt as far as I can tell.Im just wondering what could of caused this to happen because she has a long trip back to london and I dont want to just get a bolt and put the tensioner back on only for it to break again on the way home.Is this a common problem by any chance?

most vw bolts are a single use , you torque it to a certain level then give it another partial turn, it has a specific specification, . If the shop that replaced her ac compressor did not install a new bolt it could have been very weak. It appears that my 2.0 cjaa uses a different system, so I cant say for sure whats going on..

The other thought that comes to my mind is if the compressor stopped suddenly and violently it could have snapped the idler off its mount.

Id check to see the compressor turns freely, and replace the bolt.. Be sure you are turning the hub of the ac clutch and the compressor, not just the pulley.

If it is like the N/A TDI's the alternator pulley has a one way clutched pulley on the alternator that can fail and seize up putting extreme stress on the tensioner which can break the tensioner bracket or perhaps break a tensioner mounting bolt.

You could inquire at a local VW dealers parts department about the particulars of the cars alternator. If it does have a clutched pulley that has seized, then just replacing the bolt is a temporary fix.

On my 2006 BRM I replaced the tensioner 37K miles ago and reused the the tensioner bolts with no issues. For My BRM, IIRC, the tensioner bolts are not TTY(stretch) bolts.

Thanks for the replies lads.I got a spring loaded tensioner for it today in a motorfactors and a replacement belt.The clutch in the alternator seems to engage both ways when turned abruptly as the engine would make it do and it is sitting at a constant 13.8 volts with all lights on measured at the alternator.I havent checked the aircon yet but presume it as fine as it was replaced last week and was blowing out ice cold air.The aircon pumps seem to give trouble on them so it has to be changed along with the dryer condensor.

I found this on the net while browsing yesterday.


The original belt 03L 903 137 has been replaced by 03L 903 137 T and so you needtensioner*038*903*315*AH. It was changed under this Technical Product Information notice,Technical product information Transaction No.: 2021123/3*Engine: doesn't start, noises from ribbed vee belt drive, ribbed vee belt torn Release date: 05-May-2010*Customer statement / workshop findings• The engine does not start.• Noises from the ribbed vee belt drive.• The ribbed vee belt is torn.Technical backgroundThe attachment of the idler roller for ribbed vee belt has loosened.Production changeChange to spring-loaded ribbed vee belt tensioning system.Replacement of idler roller with tensioning roller