Not always the case. M62 4.4 with OE guides at over 175k miles here. I have the parts/tools for replacement ready to go in the garage. If they make it to 200k, I'm planning a total engine/heads/trans rebuild, the body/chassis/electricals/interior have worn like iron and look 1/10th their age.

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'03 X5 4.4 Sport, last of the M62s (8-03 build date)
I believe in deadication to craftmanship in a world of mediocrity!