Background - bought 2011 z4 35i that was female owned, 66k mi. Had it checked out at independant BMW certified mechanics garage. All ok; minor stuff - weeping oil pump, new rear brakes needed. Scheduled. Work done with new rear brakes, rebuilt oil pump and replaced water pump while there (beginning to fail). $2500 and six miles later, it overheats. We leave on mountain road berm and mechanic comes to get it some 2 hrs later. Starts right up so he heads downhill to shop. BIG mistake. Seizes because his assistant mucked up the fan plug. so fans neve kick in. He admits error and says will replace engine. Now on second engine (first had diff transmission type - holes would not line up) from z4 with only 26k on odometer. Flood victim - scoped cylinders and dropped pan; no water ... replaced all (13 or 15?) sensors to be safe. Car runs even BETTER than before ... EXCEPT - I notice during mountain climb, turbos check out. He rebuild turbos and yes, one set of blades had a shaft housing that separated. I drive again and runs great. On flat terrain. I return home (maybe 15 mi later) and during climb, VANOS timing good on acceleration timing change, but clatter on soft deceleration for curve approaches. He changes oil and replaces VANOS valves to my protest claiming an oil pressure issue. Better, but not gone - I don't even drive it home but right back to shop. Still some clatter on soft deceleration. He finds brass n VANOS screens (think cam bearings). Now looking for 3rd motor after 6 MONTHS of back and forth. I have a date with an attorney. Me? Sure, I am a finnicky customer - I worked for decades in mgmt with specialty equipment in niche fields where my best skill was in diagnostics.
I think the key here is knowing 2 things: Former flood vehicle. Low miles/same year. Even with scoping, car and engine stopped where they were allowing time and sludge to do their thing. Vanos helical gears are sticking; enough pressure on advance - sticking on retard leading to valve clatter and ostensibly cam failure. Why sludge? My protest was in knowing that after maybe 25 miles total, the oil looked like it had break-in zinc additive = cloudy. Mechanic error was in not totally flushing both cooling and lubricating systems, possibly a couple times, even if original change didn't reveal anything. Small time and low cost better than finding engine 3.
ANYONE experience valve clatter issues?
Love/hate my BMW z4 35i - but likely mechanic; not car
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