MK5 GTI - Cambelt

[Teutonic_Tamer]

It seems to be a big issue this cambelt on modern 4-cyl engines! I know my brother had the same with his Fabia vRS

My last two cars (Z3 2.2 and Mondeo 2.5 V6) both had cam chains - never need changing. The only things I changed on the Z3 in 100k miles was the break pads and discs. Why can't they make cars like this anymore!?

But they do also have engines with cam chains too.  But these are not trouble-free.  The Yankie designed and sourced General Motors 2.2 petrol engine (with a cam chain) used in various Vauxhalls/Opels, including the VX220 had this engine - and it suffers from horrendous problems with chains failing due to inadequate lubrication.  And with the VAG engines, when the Audi B6 S4 came out, the 4.2 V8 was modified from belt to chains (four of them), and the Yanks (yet again!) managed to ruin the chains by using incorrect lubricants.  So just by ditching the rubber belt, and replacing it with a chain, doesn't mean your maintenance issues are over.

Like I said - the new VAG 2.0 TSI engine (developed by Audi) which is in the new Scirocco and will be in the new Mk6 GTI has a chain driven cam!

[smartypants]

Right so basically stay clear of VW and Vauxhall?

[Teutonic_Tamer]

They do , thats why the new TSI is a chain driven unit now.

Only 15 years behind the times

I suppose there must be some design reason to use a belt rather than a chain though

Engineering cost being one, modern day 6 pots tend to be chain driven, BMW & VW engineering the only thing they share is the 'W', chains also stretch over a period of time and need replacement,

But chains, just like belts, have automatic tensioners.  But when chains atually stretch over and above the tollerance of the tensioner, then is 99% of the time due to inadequate lubrication.

To expand on the engineering issue - comparing a 'cam belt' engine with a 'cam chain' engine - then with a belt, you generally need just one belt, a simple low-tech mechanical-spring tensioning roller, and one or maybe two simple low-tech idler rollers.  But on a cam chain engine - there will be at least two separate chains, working in a 'relay' principle (four separate chains on the VAG V8 and V10 engines) - therefore doubling (or quadrupling) the quantitiy of components.

Then there are the actual 'costs' of the individual components.  On a cam belt engine, all the associated components (the belt, tensioners, and idlers) are all relatively cheap to make.  But on a chain engine, the components much more costly, not only to make, but also to 'integrate' into the actual engine.  Cam chains need copious amounts of CLEAN engine oil.  Cam chain tensioners generally work on a hydraulic principle, therefore need oil under PRESSURE.  Cam chain idling guides need to be 'oil resistant'.

Finally, there is the 'Noise, Vibration, Harshness' (NVH) issues.  By their inherent nature, a rubber/kevlar timing belt is very quiet in its operation (when correctly tensioned  ) - so very little engineering effort is needed to design out any NVH issues.  But chains, and their associated ancillaries are generally much more noiser - so more engineering solutions are needed to counter the NVH. 

2 thing's people should never skimp on or overlook - cambelts & tyres, both have one thing in common rubber with a shelf/use life.

Yup, absolutely.  And it is the 'TIME/AGE' issue why tyres have a date code stamped into their sidewalls - and should never really be used when they are older than 6 years.  Rubber cam belts also suffer from this 'time-aging' - and I actually find it odd that VW make no 'timescale' recommendation for the cam belt! 

[Teutonic_Tamer]

At the end of the day, its down to you as the driver and owner to maintain you vehicle and make decisions. All we, as deales can do is ADVISE you on matters. Thats what VW ask us to do.

The after 4 years condition has only just been brough in, cant remember how many years now, but in a way im sure theyre just tying to cover their backs. Everyone knows what the outcome can be if it isnt changed, and with the material used for the belt, like anything, you just dont know when it could snap.. so why wait?

You are so right there Caz - and quite brainy for a lass (dons flack jacket and runs for cover!      ).       

But seriously, you are spot on - servicing and routine maintenance is simply about preventing more expensive things from failing in the future.  Just like you would replace a brake shoe or pad BEFORE it wears out - this will then save on the cost of replacing a more expensive brake disc or drum (though with modern asbestos-free friction linings, which now have a high metalic content [except for my Audi Ceramic pads/discs    ] these do wear out discs anyway).  Routine brake fluid changes (BFC) are another - if you don't regularly change the brake fluid, then the water which the brake fluid absorbs will corrode the internals of all the brake hydraulic compontents.  Old-skool rear wheel cylinders in drum brakes were as cheap as chips, which is why there never used to be a recommeded BFC - but modern calipers, and especially ABS/ESP modules are frighteningly expensve to replace.

And just to be slightly pedantic on the actual failure issues on the cam belts - invariably, they do not actually snap, because the belt is actually reinforced with kevlar (which is what they make bullet-proof vests from).  It is usually the rubber-only teeth which simply shear off the remainder of the belt.  Unfortunately, in order to correctly inspect a timing belt (as per VWs recommendation at 60k miles), you actually need to remove the belt, and then 'reverse bend' the belt, to check where the teeth meet the main part of the belt.  OK, you can simply remove the outer plastic cover, and peek at the belt where it is reversed over the tensioner, but then you would need to manually hand-turn the crankshaft by at least full two revolutions, whilst inspecting the belt as it moves over the tensioner.  So given all that - you might just as well arrange for the belt to be changed, rather than faffing around inspecting it.

Finally, one CRUCIAL issue which no-one has raised.  Whilst it is generally agreed that rubber components, which include the cam belt are subjected to 'time' issues - we all seem to be simply basing the cam belt issue timescale from when the car was registered.  Now, with the GTI being the highly desireable and sought-after car that it is, then most were probably built to order, or were sold from dealer stock quite swiftly.  But what about all those infamous Motorpoint imports, and all those other excess stock of cars which can sit on disused airfields or port docks for maybe upto 18months or two years!  The 'rubber clock' starts counting down from when the left the factory gates (OK, technically from when the timing belt left the timing belt factory, but most major manufacturers use the 'just in time' method of supply), and NOT when the car was registered - so you may think you are being advised to change a timing belt at 4 or 5 years from when the car was registered - but in reality, that belt could actually be 6 or 7 years old! 

[ub7rm]

Who still quotes 120k miles/180k kilometers for a timing belt change?  What proof do you actually have? 

My service book, printed in 2004.  If you are that distrustful I will scan it tomorrow.

I do of course accept that things change as more real world information becomes available.

And as I've stated in most of my posts I think 60k / 5 years ish is a more appropriate timescale. 

I don't agree with VW's published 120k change as that is far too long IMO, but neither do I accept that 4 years is appropriate.

How does that make any sense anyway, who does 120k in 4 years?!  Hardly anyone, thats who!  

So you have never heard of some drivers doing 30k miles a year?! 

That was a little tounge in cheek, but most people don't choose GTI's as mile munchers.  I suspect that a very low proportion of GTI's do that sort of mileage 

[Teutonic_Tamer]

I agree with that.  But what is suspicious is why VW have suddenly changed it to 4 years in the UK but not worldwide?

I strongly disagree with your comment that it is only VW UK who have downwards revised to the 4 year mark!

Yes its part rubber, not strawberry lace!  Unless its been contaminated by oil the belts will last much longer than 4 years.

Disagree again.  OK, I accept that oil contamination on a rubber belt is going to cause issues, but then any 'oil leak' is way outside the scope of 'routine maintenance' or 'scheduled servicing'.  Oil leaks, and their co-related problems need repairing under a term such as 'unscheduled repairs'.

As has been repeatedly said, rubber naturally deteriorates over time due to the natural atmosphere.  Ozone is one of the worst causes of rubber deterioration, and then closely followed is oxygen.  Now if you want to kill off all human and animal life on this planet by removing the natural 20% of oxygen present in the earths atmosphere - then you are probably a better scientist than Steven Hawkins, and all the other boffins combined!  So, in the interests of preserving life, I would rather keep that oxygen in the atmosphere, and continue to bite the bullet and replace rubber components every 4-6 years! 

That said I guess there is an argument that frequent starts more typical of low mileage are harder on the belt than constant driving high mileage.

I do tend to agree with that.  But what about the 'boy racer' who thrashes his car.  Or the idiot who thinks it is cool to rev the engine over 3000rpm without any load, or the doddery old farts who never get the car warm enough to burn off any atmospheric contaminents away (and these not necessarily need to be 'frequent start' or 'short journey' - they can actually be long journeys, but are just too scared of exceeding 2,000 rpms, incase it uses more fuel or some other stupid reasons these slow cnuts seem to use).  Because all these scenarios will also have a negative effect on the longevitiy of the belt.

5-6 years, 60k is a sensible time to change.

Again, I don't mind agreeing with that - but providing you take into account my other concerns raised.

If they were nylon belts I could see the sense but ASFAIK they are not (on the 2.0T FSI anyway).

WTF are you on about?   Timing belts have NEVER used nylon - have you been wearing your grannies tights?    All timing belts use continuous strands of kevlar or aramid as a strengthening 'spine', and are simply encased in rubber.  But the teeth are generally devoid of any continuous reinforcement - which is why the teeth shear off.

Thanks to long life servicing VW are not seeing as much service related monies coming through the door and have changed the belt schedule to generate a bit more cashflow.

That is just a cynical, ill-informed POV.

If you carefully studied the detail of the LongLife regime, then there is only a small minority of petrol engined cars which are 'cheaper' to maintain on the LL regime (diesels are better in this respect).  However, for most cars, which will have been 'default' set to LL regime, but incorrectly set to LL, then the LL regime will actuall cost them MORE to maintain.

I appreciate some of you are taking the safe road without question, and in the words of our resident philosopher, ETTO, hail mary etc.  But if VW changed it to 3 years?  2 years?  would you still blindly follow this advice without question?  Maybe wonder why this change in schedule has not been implemented world wide?

You still have no proof that 'worldwide' VWs interval is still 120,000 miles!       

For the record, virtually ALL motor manufacturers recommend timing belt changes at an absolute maximum of 6 years.  Some also recommend upto around 80k miles, the vast majority recommend around 60k miles, and some will state 4 years.  As I have repeatedly stated, 40k miles is very much on the lower end of the spectrum, and I have freely recommened going upto 60k miles - but I have also qualified that 60k recommendation with some serious other scenarios to ponder over.

But you now seem to be verging on the rediculous - afterall, what evidence can you provide that either VW, or ANY manufacturer has ever recommended, or might even be considering altering the schedule to 3 years?  Absolutely none.

If it is the case that belts are now failing earlier than expected and there is a sound technical reason why VW have implemented this change then you still have to ask the question why are VW now churning out shyte belts?  Why are we taking a step backwards here?

First, Volkswagen do NOT make timing belts.  They use ContiTech, probably one THE most highly regarded timing belt manufacturer in the world! 

Next, VWs own 120,000 miles change interval was just pure 'pigs might fly' - simply to artificially create to the motoring press and fleet managers of how cheap their cars were to maintain.  Once the Mk5 Golf GTI, and all the associated TFSI engine users 'honeymoon period' was over with the press and fleet managers - then VW sensibly revised their cam belt change intervals to co-incide with the industry standard norms.

But you still completely miss the point.  A cam belt change is . . . .

'preventative maintenance' ! ! ! ! !

[Teutonic_Tamer]

Right so basically stay clear of VW and Vauxhall?

LOL, and dont forget to avoid French too, because the belt on the 1.9 TDCi are utter, UTTER barstewards.

Then you can avoid Jap and Asian cars too - becuase whilst they may be a tad more reliable (actually, only Toyota are proven to be more reliable - whereas Nissan and Honda both have rather poor reliability issues), they are utterly soul-less pieces of turds, and you will die of boredom at the wheel! 

[smartypants]

Right so basically stay clear of VW and Vauxhall?

they are utterly soul-less pieces of turds, and you will die of boredom at the wheel! 

 

[Caz]

At the end of the day, its down to you as the driver and owner to maintain you vehicle and make decisions. All we, as deales can do is ADVISE you on matters. Thats what VW ask us to do.

The after 4 years condition has only just been brough in, cant remember how many years now, but in a way im sure theyre just tying to cover their backs. Everyone knows what the outcome can be if it isnt changed, and with the material used for the belt, like anything, you just dont know when it could snap.. so why wait?

You are so right there Caz - and quite brainy for a lass (dons flack jacket and runs for cover!      ).       

haha, thanks  nice to know VW have trianed me well.. and that i actually retain all the information.lol

finding your knowledge interesting though too.. 

[Teutonic_Tamer]

Who still quotes 120k miles/180k kilometers for a timing belt change?  What proof do you actually have? 

My service book, printed in 2004.  If you are that distrustful I will scan it tomorrow.

Sorry, I'm not doubting you on what the service book states.  But I was doubting on where you think that for the rest of the world, the entire Volkswagen Group (VW, Audi, Seat, Å koda) are still using 120,000 miles.

And just to clarify, my service book was printed March 2006 for May 2006 vehicle production - and it still states 120k miles for the timing belt.  But also on the 'stupid VW intervals', it also states 6years/60k miles for changing the air filter element and the spark plugs too!    Both worn out plugs and a partially clogged air filter will have noticeable effects on emissions and fuel economy (not to mention any loss in performance) - so that really isn't being very 'green', which VW are claiming to be.  

I do of course accept that things change as more real world information becomes available.

OK, cool.  

And as I've stated in most of my posts I think 60k / 5 years ish is a more appropriate timescale.

Me too.  But at 5years/60k miles, there really is no scope to 'put it off'.  It really would need to be done then, rather than an owner/driver whinging that they can't afford it (OK, again, like I said, you may also be lucky with the belt lasting six years, but that really is pushing it).

However, at least with the 4 year recommendation, it can all be tied into the 'biggie' 4 year/40k mile service - and if the customer genuinely has reason to delay, and the discipline to actually get the job done later, then that is not a problem.  I personally think the 4 year recommendation is just a good 'safety net' - afterall, with us all being 'dub-lovers', we wont want our dub reputation being tarnished by bad press from snapping timing belts!    

I don't agree with VW's published 120k change as that is far too long IMO, but neither do I accept that 4 years is appropriate.

I have always strongly disagreed with any motor manufacturer over such stupidly long and unreasonable timing belt intervals.  Vauxhall were also guilty of this too, a while back.

But I also disagree with having no scheduled replacement interval for a petrol fuel filter.  And I disagree with 'filled for life' transmissions (OK, it doesn't affect the DSG) which affects all front wheel drive manual and auto transaxles, and all rear wheel drive manual/auto transaxles and rear final drives..

But from purely an 'engineering' point of view - is a 4 year timing belt change interval appropriate?  I would say no.  But for the 'average Joe public', then 4 is fairly reasonable - maybe a tad early - but better to be safe than sorry, especially in this day and age when an aweful lot of cars seem to sit on disuesed airfields for very long periods of time.

How does that make any sense anyway, who does 120k in 4 years?!  Hardly anyone, thats who!  

So you have never heard of some drivers doing 30k miles a year?! 

That was a little tounge in cheek, but most people don't choose GTI's as mile munchers.  I suspect that a very low proportion of GTI's do that sort of mileage 

OK, I do agree that not many GTIs may be mile munchers - but the 2.0 TFSI was fitted in many, many other VAG cars, including the Å koda Octavia vRS - and many of these are used by Police forces and taxi drivers - who are all known to rack up the miles.  Anyway, we are splitting hairs a little on this particular issue.