Cambelt wear question

[mbelle]

As I'm not the mechanic, what is it that typically wears your cambelt?
I.e. is it the higher the revs or the more throttle?

I only ask because, if one was trying to 'limit' wear to his/her current belt, would one drive avoiding high revs, or avoid using full throttle?? Or is it just general engine running that wears it?

[dace]

High revs = full throttle? Change it every 40,000 miles, it's not worth the risk.

[bigandyw]

i've known 3 cam belts snap, 1 of mine on an old sierra snapped at 1200 revs on its way to the scrap yard!! lol

One mate had 1 go when he started it the morning after driving his 16v MK3 astra 85 miles the day before

And the last and funniest was a mk3 xr3 which he managed to change from 2nd to 1st instead of 3rd, the cam belt wasn't the only broken component of that miss hap! but that was pure accidental rather than over due!!

Think lower revs seem to put more strain on the belt as the valve train has no momentum unlike at say 4k when it has rotational momentum, similar to trying to turn a fly wheel say from stand still as opposed to when its all ready turning!


Definatly worth changing it on time BUT i'm sure you'd get at least 5% margin of error, manufacturures will test many untill they snap then probably reduce the findings by 30-50% so as not to incounter warranty claims if a belt snapped at 39999 miles of pure flat out abuse of a brand new car!

[mbelle]

Cheers both - it's not that I want to take the risk, it's just that it's booked in with Grizz end of September (earliest time I can due to funds), but only have 1300 miles left until my 40K threshold; typically, I do ~80-100 miles per day!

Running out of miles...

May have to hire a car...

[bigandyw]

so you'll only be less 1500 miles over when u can get it in? i'd ask Grizz if he's ever known of any go so close to the 40k mark!

Its only 3.5% over its interval, and i don't for a minute think any manufacturer would allow a belt interval to be that close, especially as yours isn't tracked or abused like some which will easily make the 40k!

Oh and leaving your engine running won't clock up the miles but it will still wear your belt, so they have to allow for that!

[mbelle]

Very true...
I'll see how I feel the more I get to the 40K mark - still may hire that car; last thing I want is my belt snapping!

Cheers Andy!

[SJS]

The belts could probably last 80k miles easily enough, although they may stretch a tiny amount. for a belt to fail in and around 40k would be hugely unlucky.

[p.binks]

Hi

Do Not Trust the mileage as a way to gauge how the belts condition is,change it ASAP as its over 5 years old and the recommendation is 40,000 miles or 5 years,I speak here from bitter experience of having one let go at high revs.

Cheers "Bingo"

[mbelle]

Hi

Do Not Trust the mileage as a way to gauge how the belts condition is,change it ASAP as its over 5 years old and the recommendation is 40,000 miles or 5 years,I speak here from bitter experience of having one let go at high revs.

Cheers "Bingo"

So are you saying change it before it gets to 5 years old (or 40K) and change it ASAP if it is 5 years old?

Out of curiousity, what did you experience when it went?

[biggingermuff]

Moderating your driving style is not the way to prolong belt life i agree with others don't take the risk............

[Rs4Fan]

Hi

..change it ASAP as its over 5 years old and the recommendation is 40,000 miles or 5 years,I speak here from bitter experience of having one let go at high revs.

I followed the 5 year rule as well and replaced it early. Just looked at the service booklet and there is no reference for the 5 year timing - just 40k miles. Is it simply a recommendation?

[kiwi_rs4]

I followed the 5 year rule as well and replaced it early. Just looked at the service booklet and there is no reference for the 5 year timing - just 40k miles. Is it simply a recommendation?

I think Audi amended the service interval. In NZ the interval is 5 years/60,000km (37,000mi). When I bought my RS4 last year I had the dealer change the cam belt as part of the deal, even though the car had only travelled 48,000km.