My friend just had to replace the oil cooler in his A8, he spent close to $2000. It had symptoms of a bad head gasket(oil in coolant), and the dealer diagnosed bad headgaskets. A mutual friend called the oil cooler and we pressure tested it, sure enough it was breached internaly.

IMHO, a six cylinder BMW 5 series is a pretty diy friendly car and it's reliable except for the auto transmissions, which like to eat the reverse drum in 1999-2004 models. Though they could be had with a manual trans.

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"I was a dirty bird, Carol's not grungey - she's *****in" John Milner....American Graffiti