Zahnriemenwechselbedingungen: km vs Jahre | Posts 32+

Interesting, in T4s with 5-cylinder engines, whether gasoline or diesel, that are often driven for short distances and in city traffic, the water pump often fails, causing the timing belt to become misaligned. You can probably guess the consequences .
For long distances, whether driving at full throttle or normally, they easily last until the scheduled maintenance intervals! My acquaintance drives a T4 ACV with 880,000 km and changes the timing belt and water pump every 150,000 km! Driving profile: Almost exclusively on highways at night, mostly 140 km/h.
A disabled transportation service with 22 T4 vehicles, all from ACV, mostly operates in urban areas with frequent starts. Back then, hardly any of them lasted more than 90,000 km due to the water pump . The replacement interval was reduced to 75,000 km, and since then, all of them have easily exceeded that distance! Therefore, my opinion: Short routes, maximum 75,000 km, long routes, 120,000 km, and for mixed operation, 90,000 km.

Sprinter vans often last for over 500,000 km without needing a chain replacement. Some even reach a million! More commonly, the "rail pumps" or injectors fail.

Aha.

So, are you more inclined to believe that the (cold) starts are what wear out the starter motor or the water pump, rather than the years with low mileage?

Yes, it's more the frequent fluctuations in idle speed that cause the water pump bearing and tensioner roller to experience more stress than at higher speeds. The same applies during starting! Look at the tensioner roller without the timing belt cover while the engine is running; see what happens at idle speed and at 3000 RPM.
I'm sure you can understand why .
With very low mileage, I would recommend replacing the timing belt and water pump after a maximum of 10 years, or sooner if specified by the manufacturer.

Okay, I'll see, if I have to replace the timing belt on my AXC in the spring .