Timing Belt Replacement: Mileage vs. Years

Hello,

In all lists and publications, you will find that our timing belt replacement recommendations depend on the mileage of the vehicle. For example, for Audi vehicles from model year 2002 onwards, the recommended interval is 120,000 km (later even 150,000 km, and previously 90,000 km).

"Now I'm currently researching the timing belt for my sister's Twingo and I'm finding that Renault specifies for the gasoline engines a maintenance interval of '120,000 km or 5 years,' which is an additional restriction on the maximum age of the belt."

It actually makes sense, because these things also age. Why isn't this the case with our TDI engines? Have I overlooked something, or did everyone simply assume that you could easily achieve the 150,000 km service interval within 5 years with a diesel engine?

I've only driven about 100,000 kilometers in just over 6 years, so based purely on mileage, the change could probably wait until the summer of 2009. However, you don't want to take any risks. The condition was excellent during the last check (at 95,000 kilometers), otherwise it would have definitely been replaced.

What do you think?

Best regards,

Jan.

That's exactly what surprised me when I disassembled the Corsa last weekend.
Opel also has this "km or hours, whichever comes first" requirement.

I strongly believe that a certain minimum usage was required for diesel vehicles.

m;

"In my case, the recommended service interval was also 120,000 km or 5 years."

I had it replaced as a precaution after 80,000 km / a little more than 6 years.

The latest belts last significantly longer.
From an internal communication, I understand that the new HNBR belts last longer.
If the manufacturer desired, a warranty of at least 100,000 km could be offered. During testing before production release, vehicles are often driven for 160,000 to 240,000 km!

The oval wheel technology reduces peak loads by approximately 40% (2-liter TFSI, AUDI).

The critical points are the roles of oil, foreign objects, and lateral movement.
And that's something that needs to be checked during maintenance!
However, belts are still an interesting topic, and when they work properly, they hold up well.

"Oil belts" are also being tested (for applications with a smaller footprint).

Hi,

Quote:

If the manufacturer desired, a warranty of at least 100,000 km could be offered.

Mine has already reached 120,000 km... but it's not exactly the newest model.

So, you mean that with the newer belts (but from when does something count as "newer"?), aging is no longer such a big issue?

Best regards,

jan

Hi,

At the AEL service intervals, it has always been 120,000 km, and mine has always managed to last that long. Tomorrow, I'm going in for the fourth replacement. The problem is usually more with the tensioner pulleys or the water pumps.

"However, the minimum shelf life is normal. It's just that the manufacturers' specifications are extremely conservative. In the past, Opel used to specify a 4-year interval for gasoline engines, while VW/Audi usually only provided mileage-based recommendations. Our old Passat 32B TD also had a 120,000 km (approximately 75,000 miles) interval without any age restrictions. However, the condition should be checked every 30,000 km (approximately 19,000 miles)."

If the mechanical condition of the belt is good (no signs of wear on the sides, no fabric tears inside, and the width is still relatively original), then you can probably drive it up to the mileage limit without too much concern. In my car, shortly before reaching the 'lifespan' limit, the belt didn't seem new at all. The tension was okay, but the fabric had small tears on the inside.

Best regards from your neighborhood.
Olli.

teileklaus wrote:

..., that the new HNBR belts last longer. If the manufacturer wished it, one could offer a warranty of at least 100,000 km...

After a picture, a belt with a red stripe.
Hydrogenated Nitrile Butadiene Rubber = Polychloroprene with glass fiber/aramid reinforcement.
The rollers are lubricated with "another heat-stabilized high-tech grease" (whatever that may be).
"As far as I know, the belt is not yet available for sale, but as I mentioned before, it's an OE part."
Until then, there's still my affordable SNR option - or does anyone believe such a belt would actually cost €25?

Hi,

Quote:

However, the condition of the component should also be checked every 30,000 km.

Certainly. Every time I change the oil, I remove the cover and inspect the clutch disc, measuring its width. Last time, it looked great and was still far from the wear limit.

Quote:

Until then, there's still my "günstigen SNR" option – or does anyone really believe such a belt could be available for €25?

Probably not. The goal is more likely to ensure that the material costs at least as much as the labor hours required for the belt replacement.

Best regards,

Jan.

Okay, here's a silly off-topic question on the side...

Why are timing belts still used today? Other manufacturers offer chains or toothed belts that are designed to last almost indefinitely.

Even though a BMW or Mercedes is more expensive, the extra cost is often offset over the lifespan of the car, but mainly due to the frequent and annoying need to replace those belts.

Does the belt-drive system have any technical advantages besides a possible weight reduction?

ObenbeiMutti wrote:

.......Why are timing belts still used today? Other manufacturers offer chains or toothed belts that last almost a lifetime... Even if a BMW or Mercedes is more expensive, ..

Not entirely black and white.
I know some Vitofahrer (drivers of Vitofahrer vehicles) who had to replace a chain with an engine problem while abroad.
Running noise, chain tensioner, and price are still issues to be addressed.
"I'm just saying, if we gave the supplier a little more money, the first planned maintenance interval with the first belt would be at 150,000 km, and then the replacement price would be acceptable after 5-7 years."
Didn't the Polo 1.2 three-cylinder engine also have chain problems?

ObenbeiMutti wrote:

Just a silly off-topic question on the side... Why are timing belts still used today? Other manufacturers offer chains or toothed belts that are designed to last almost indefinitely.

Hi,

"However, I've also read about replacement intervals for timing chains, although that was quite some time ago. Nowadays, there are also car manufacturers that specify replacement intervals of 240,000 km and 10 years for the timing belt."
The reasons lie in the costs; for a timing belt, you often only need a certain number of shaft seals to ensure everything is sealed properly, whereas a chain requires more elaborate sealing systems. Furthermore, maintenance would become more expensive.

But again, changing the subject.

Regarding a timing belt, it's possible to observe its condition over the winter. After a period of inactivity, the belt takes on the shape of the timing drive system. Over a longer period, plastic deformation may occur within the belt, which is certainly not beneficial for its lifespan when it's put back into operation.

Hi,

Quote:

If you can wait "a little bit" longer, there are engines that don't require a timing belt, chain, or any other mechanical connection to the camshaft.

Why not just eliminate the camshaft altogether? If you use electric actuators for the valves, you wouldn't need a camshaft anymore... although a camshaft driven by a stepper motor would be a nice intermediate solution.

I don't think the world will be better then; it will just break, and then we'll have the finest kind of valve failure.

Best regards,

Jan.

"Yes... the engine manufacturers will be thrilled... completely freely adjustable valve timing... one more degree of freedom... I'm really curious to see when the first manufacturer will dare to implement it in a production vehicle, but I don't expect to see it in the next two model generations."

Okay, so the bus has front wheel drive. When you start it cold with the hood open, it rattles quite a bit. However, due to the seemingly good insulation, very little is audible inside, and maybe I'm just used to diesel engines... but it doesn't bother me. Where there's wood being planed, there are shavings, and in my world, a diesel engine should sound like a diesel engine. I grew up with a 190D, so I'm used to the sound of diesel engines.

Unfortunately, the timing chain is not always a maintenance-free component, as the tensioners can sometimes fail prematurely. If the tensioner fails and you have a chance to repair it before the timing chain breaks, the repair is neither cost-effective nor user-friendly compared to a timing belt solution.

Timing belts, in my opinion, are a necessary evil. The replacement itself is quite simple, but disassembling everything around it is incredibly frustrating. The designers really need to rethink the layout.
But even in that case, there are good and bad solutions...

No, thank you, Jochen. I'm a pessimist based on experience.
For me, anything new is initially worse than what I already know.
You don't always have to reinvent the wheel.
A well-designed invention is always better than a cheaper and less reliable one.
"In my apprenticeship in 1975, Ford OHC engines with a single overhead camshaft and without a water pump drive already had a timing chain. And it was quick to replace."
Of course, I support the flexible early warning system (VÖZ).
But if valve failure only happens once, I don't want to be the one who has to deal with it in a real-world field test.
I don't quite understand the policy. As soon as the system is mature and practical for use in the workshops, they come up with something new!
See: PD/CR, oils, rear brake pads, turbocharger, timing chain - perhaps Mercedes, with its more cautious approach, is actually better for these reasons (and can still afford to be more expensive).
Ford once advertised that the Fiesa could be serviced by any reputable mechanic in 1.5 hours upon its release, and it became a huge success, just like the Beetle. There's a lesson to be learned from that.
Progress through technology? No, thank you - especially when it's tested at the customer's expense.
My motto:
Less is more

ObenbeiMutti wrote:

... Other manufacturers offer chains or sprockets that are designed to last almost indefinitely. ...

I hope you are aware that even for reputable German manufacturers, there is a replacement schedule for chains and sprockets, which is around 200,000 km! Such a replacement costs significantly more, often two to three times the price of a timing belt replacement.

Even a chain won't last forever!

Why not just eliminate the camshaft altogether? If you use electric actuators for the valves, you wouldn't need a camshaft anymore... although a camshaft driven by a stepper motor would be a nice intermediate solution.


Yes, I've 'heard a little bird chirp' in that direction and in another direction as well.

So, even without a camshaft, you can still come up with something.

Yes...then the engine manufacturers will be happy...completely freely adjustable valve timing...one more degree of freedom...
Here lies one reason for this research:
Torque at low RPMs, overlap at high RPMs, and during starting.
'All the things you can do with it, and all the things you can leave out.'
If one is completely independent of a fixed valve lift, one can imagine even more 'tricks' that support downsizing.
I'm really curious to see when the first one goes into mass production, but I don't expect that to happen for the next two model generations.

So, the next one definitely won't do, as it's good to have variable valve timing.


I don't believe that the world will be better then; instead, the thing will just break down, and then we'll have the finest kind of valve problems.

Certainly, because open-cycle engines are not known for high compression ratios, which makes it difficult to achieve high performance and efficiency.

But we are going off-topic...

Best regards, Jochen.