Polo GTI 9N3 - Timing Belt Change Guide

[qbosaur]

Hi everyone,

I drive a 2006 Polo GTI and recently did the major 90,000km service which involves changing the timing belt. I also changed the tensioner pulley, water pump, thermostat and accessory belt as preventative maintenance.

It was difficult finding the necessary information on the web (and there is also a lot of misinformation and poor workshop practice too!), so I decided to chronicle the experience on my blog : Engineering Mayhem: VW Polo 9N3 GTI, 1.8T BJX Engine - Timing Belt Replacement Guide

Hopefully this is useful to others DIY'ers who want to do the same service.

Cheers.

[hardy_bm]

This is great. Thank you.

[h100vw]

Good write up and kudos for taking pictures on the way. I have done a few in recent times with the engine/belt failures on the Squib and a couple of other peoples projects that have come my way. I went to a manual tensioner on my Polo, from Integrated Engineering.

Just curious, you reused the hyd damper and tensioner pulley? Of the parts in there, the damper is the one bit that would be most likely to cause a drama if it failed. Just saying. Noteworthy point is that the Polo damper is different to all the others, making it more expensive too.

Turning the heater to hot makes no difference to the flow of coolant in the heater core. Coolant flows through it all the time. Only mk1s have an actual tap in the line.

Gavin

[qbosaur]

Hi Gavin

Good write up and kudos for taking pictures on the way. I have done a few in recent times with the engine/belt failures on the Squib and a couple of other peoples projects that have come my way. I went to a manual tensioner on my Polo, from Integrated Engineering.

Thanks

This "manual tensioner" sounds interesting. Is it spring loaded such that it can respond to belt stretch over time or engine load variations (similar to the accessory belt tensioner)? Or is in a fixed position?

The workshop manual outlines a procedure for setting the clearance between the hydraulic tensioner body, and the plate on the tensioner pulley, to be 4mm. It also mentions that this clearance may be reduced to 1mm when the engine is warm and running - which suggests to me that the tensioner acts to maintain a constant tensioning force on the belt as opposed to locking down its position. Your comment about hydraulic dampening makes sense as well.

Just curious, you reused the hyd damper and tensioner pulley? Of the parts in there, the damper is the one bit that would be most likely to cause a drama if it failed. Just saying. Noteworthy point is that the Polo damper is different to all the others, making it more expensive too.

I reused the hydraulic damper / tensioner, but replaced the tensioner pulley. In retrospect, it would have made sense to replace it as well, but I balked at the price (quote was around $260). It seemed to be in good condition when I pulled it out (as did everything else!), so hopefully that decision doesn't bite me in the future. (At the rate I'm going, it will only be another 4 years before I reach the 180,000km mark and need to do this service again!)

Turning the heater to hot makes no difference to the flow of coolant in the heater core. Coolant flows through it all the time. Only mk1s have an actual tap in the line.

Hmm, that makes sense now that I think about it.

I recall reading in a generic coolant flush procedure that turning on the heater causes coolant to flow through the heater core. However, this makes no sense, as you would have really poor temperature control that way - it would either be cold, or very hot. It also doesn't explain why the air temperature can change from cold to hot, and then back to cold again in a few seconds.

Am I correct in saying then that the temperature setting controls the amount of air that travels through the heater core on the way to the cabin?

Cheers,
-Wilson

[PoloGIT]

Thanks for this, Wilson. Had a read of your guide and think I'm confident/crazy enough to have a crack at this myself soon. Guess I'll be adding some more tools to the collection in the process

[Bullet Fast]

Anyone know if there's compulsory bolt changes during the belt change? Engine mounts or harmonic balancer screws?

[Hilton_K]

Unsure if there is a mandatory change but I would check them all for stretching prior to reinstal. If any are torque turned during tightening sequence I would change these as well.

[h100vw]

Anyone know if there's compulsory bolt changes during the belt change? Engine mounts or harmonic balancer screws?

Mine have been well re-used. Not saying it's correct, but no failures thus far.

[Bullet Fast]

Same!

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[Umai Naa!!]

You usually get the necessary new hardware when you buy a decent European timing belt kit, anyway. Mainly new nuts and washers for the tensioner and idler pulleys.