Morning all!

Newbie to the forum, I've had my Octavia 1.9Tdi estate for seven years.

Over the last 18 months it's developed a recurring problem - due to some vibration in the engine, the belt tensioner on the engine (ALH) keeps on snapping. It's the bracket which joins the engine block that keeps on shearing.

I've gone through about 4 of the things and I'm now getting fed up.

The latest issue (after recently replacing the tensioner, and various pulleys for £280) is a sticky EGR valve. I read somewhere that this can cause an engine knock - could this be making the problem?

The common cause is the freewheel pulley on the alternator not working properly.

The EGR valve is a plunger style assembly, so unlikely to sticky as such, imho. There is a butterfly style anti-shudder valve in the EGR assembly which is known to stick if the EGR assembly is dirty.

If the car is euro3 (which it should be in 2003) I'd just blank the EGR.

Brilliant, that sounds good. Do you know if Euro or GSF stock the pulleys?

I got my pulley from a VAG supplier in Bristol. Not sure if ECP or GSF and the like supply them - guess a quick phone call will reveal the answer. Note you will need a special tool to remove the old pulley / fit the new pulley which isn't cheap, unless you happen to have friendly local garage.

In my case I removed the alternator and got the parts supplier to change the pulleys over (mine had half snapped off) for a few quid.

Cheers thanks for your help - really appreciate it. It's been driving me mad (not to mention the Mrs) when the tensioner keeps on going. Last time before now was on the M6 on the way to Blackpool.

Luckily got a local garage to fix it, there was one part they couldn't get, and I bet it was the alternator pulley...

You can get the pulleys from GSF or ECP as well as a VW/Skoda dealer, TPS or even Ford. As mbames said you need the special tool to take the pulley off and the alternator has to come out to remove the pulley - there isn't enough space between the alternator and the side of the engine bay.

I would also look to change the tensioner (again) and the aux belt at the same time.

Oh the pulley is only £20-30, cheaper than the tensioner.

Thanks for your help, I'll keep you informed!

Spoke to my local GSF who have got the pulley in the post for £31. Managed to source a 2nd hand tensioner as well (don't want another £120 going out before I know the problem's fixed!).

The tensioner should only be £50-60 for a new one.