A $3k E53 is going to cost half that a year to maintain on average. I spent probably more than that per year on average to get 120k miles out of a car I got with 65k. And that one had few options and a manual transmission--but was a Gen1.

Like others said, some years I just changed oil, but other years I had to rewire the engine, replace the accelerator and R&R all the half shafts.

Statistically speaking, you are better off spending the least amount of money to get the lowest mile E53 you can find. If that means putting 3k into an engine swap on a 120k mile chassis...then there it is. But remember, at 120k, your suspension is probably all approaching end of life if it has not been changed, and nearly every piece of the suspension outside the K member is a wear part.

As others also mentioned, the cooling system is garbage, and I keep spares of all the hoses and a spare expansion tank on hand constantly. The motor itself is awesome...BMW has been making inline 6 for literally 100 years.

But they cut costs in other places, relying on people getting a new car every 2-3 years as their prime buyer base. A part life of 65k is fine if you only own the thing for 3 years from zero miles and trade it in for a new model before warranty runs out.

As for German cars generally, they are over-engineered to emphasize performance/ride quality at the cost of part life and simplicity of repair/parts.

My E53 is not a daily driver anymore and is just a hobby. Otherwise, it would have been a money pit years ago.

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2001 E53 3.0 5pd