Quote:
Originally Posted by RyanGMW
I will chime in here. 13yr BMW master tech and indy BMW shop owner. Here's my past 6 months experiences with N55 engines.
Started a small car lot, bought a 2012 X5 N55 with "engine noise" at 82k. Assumed belt tensioner or something. Nope. Spun rod bearing cyl #2. Replaced engine with used motor ($4400 used engine) and installed all new rod bearings and bolts to be safe with updated S55 numbered bearings- car happy and sold.
Then 1 month later, a new customer brings in 2011 335i N55 E90 with 98k on clock, just bought at some random used car lot- has knock. Spun bearing. Dealer wont help him (less than 24 hours of his ownership).
Customer brings in 2011 X5 3.5i for PPI. Road tested, full load at 4500rpm I hear a knock. Rev up in neutral back at the shop, 2k rpm- rod knock. Pull out oil filter, full of metal shavings. Tell customer not to buy it. He brings me another X5 N55 today, pulled filter to see that one and it was full of shavings too but no noise (92k dealer maintained at 8-10k intervals).
Last week another shop towed in a 2011 X5 with N55 not running. They replaced a bunch of parts to no avail. Finally figured out DME had failed and wouldn't fire the injectors or coils. $2500 later it runs again and customer wants to dump it and run.
I Bought another N55 X5 with cyl #6 misfire and air plausibility codes. Removed valve cover after extensive time and testing to check valvetronics. Camshafts are rusted and lobes are worn to point of not opening valves at idle- replaced both camshafts, and then shortly after the valvetronics motor failed. back apart again....
In my recent experience, The N55 is a fragile and dangerous engine to own past 80k. I owned a 2012 X5 from 19k miles to 95k miles and it had its share of issues (57k OFHG failed, 59k valvetronics motor failed, 84k PCV/valve cover failed). I have a 2015 435i currently and it scares me to think of owning it long term... I know I only seen broken cars as thats what I fix for a living so maybe there are bunch of N55 success stories out there, but lately they seem to be failing left and right, maybe someone can encourage me that its only a temporary wave but my local dealers refer to the N55 as "Total Junk" and they see tons of rod bearing failures there and wont help most customers!
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The N55 is probably one of the most common BMW engines out there for F chassis vehicles.
I have 105,000 miles on mine and those include track miles. No major issues so far. I've had the OFHG and oil pan gasket replaced under the extended warranty.