2010 Golf 1.6 TDI cambelt tensioner stud question

[gordik]

Hi,

looking for some help

Have my partner's 2010 Golf 1.6 TDI booked into a VW main dealer to do a cambelt/water pump replacement and have some questions about the tensioner stud, this will be the 2nd cambelt change and reading on here there seem to be failures if the stud isn't replaced.

1. is the tensioner stud replacement part of the normal cambelt change or do I need to request it ?

2. seems the best solution is to replace the M8 stud with the M10 -> M8 mm stud, is that something people have had done or is the M8 replacement good enough ?

3. Most of the tensioner stud threads on here are from a few years ago, has VW solved the issue and it's no longer a problem ?

Was considering doing it myself, but this tensioner stud issue just seems a nightmare and don't want the grief if it subsequently fails.

Thanks

[Crasher]

You have a CAYC code engine which uses the M10/M8 stud and the dealers will use kit 03L 198 119 F which from memory (I need to check the ETKA kit list at work) does contain the M10xM8x73 stud N 909 055 02 which retails at £1.48 on its own. I know some mechanics with VAG experience get a little nervous about fitting a new M10xM8 as it actually increases the rate of failure due to incorrect installation whereas with the M8xM8 stud this cannot happen. We always fit a new stud and ALL fasteners removed during this job which is also critical if you don’t want to literally have the engine fall out, which does happen... I would be worth asking if they intend to change the water pump which is widely considered essential. Also I would point out that we only fit genuine belt kits and water pumps even though we are independent specialists as the dealer backed two year parts and Labour warranty are a comforting feature when we buy from TPS but we have never needed to make use of it.

[gordik]

thanks for the info, much appreciated, shall have a chat with them

[gordik]

Checked with the dealer and 03L 198 119 F kit doesn't come with the tensioner stud and instructions say to replace the tensioner stud if damaged, will the original stud always be an M8 and require drilling out/tapping to fit the M10/M8 stud ?
Not sure what the dealer does and didn't speak to a tech.

[Crasher]

You have a CAYC code engine which uses the M10/M8 stud

It already has the M10 into the head for M8 on the tensioner, in almost all cases this comes out using a stud extractor and the new one is fitted by the old double nut method, it is just nipped down but the critical point is the transition radius between M10 and M8 MUST be below the face of the head or the tensioner will sit on the radius and the stud will snap, that's why mechanics don't like changing them. Occasionally when removing the stud it will pull the thread in the head, especially if it has been done a few times and in that situation we use Time Sert inserts; other people use Helicoils which are fine. If one snapped then it would have to be drilled out in situ with great care and accuracy, not an easy job but usually they only snap in service, not during renawall so the head would have to come off anyway. A few weeks ago we had one that was really tight in the head so we put the induction heater on it until it glowed, left it to cool and it wound straight out, snapping one during a belt change would be nasty. One of my grease monkeys did a CAYC belt yesterday. I have checked ETKA, no the kit does not include the stud.

[gordik]

thanks, missed the bit in your original reply about CAYC being M10.
If VW are not including the stud in the kit then wonder if they think it's no longer a problem or just don't want to admit it's an issue.
One last question, when you say use timeserts would that be an M10 timesert with an M8 stud or would you drill out the hole to allow the original M10 stud to be fitted ?
thanks again, maybe time to get rid before more CAYC issues appear.

[Crasher]

The OE thread being M10 the Time Sert and Helicoil method is to tap the bore to M12x1.5 and fit an insert, in certain cases I have fitted an insert inside an insert to save a casting and the job.

[gordik]

thanks for your help, would definitely be booking it in with you if I lived closer