Why is the cylinder head cracking

Why is the egr valve stuck?

Why is the water pump with a plastic body leaking?

I even changed the egr water pump for the second time and the parts are all original. I'm not counting other minor faults. For example, last year the winter was cold. We couldn't drive our vehicle because of the diesel freeze. About a month or two. But when the spring comes, the trouble is over. Fuel Shell Euro5. because the fuel pump is under the car and has a simple protection

I just changed the oil pump and they told me to replace the replacement part, but it was very expensive. and we were advised to put 10w60 oil instead of 5w30. because there is a gap. Is 250 000 km too much?

A friend of mine told me that German cars break down a lot. But I didn't believe it then. Now my perspective has changed.

this is erzurum turkey And Audi is not the only vehicle, even 30-year-old vehicles do not cause this much trouble.