After working on these engines for years, I've noticed a few patterns worth sharing. While the 2016 RX engine is remarkably reliable, it's not without its quirks. The water pump is a weak point I've replaced more often than Toyota would like to admit - typically failing around 60-80K miles. You'll notice coolant leaks near the front of the engine or potentially an intermittent temperature gauge spike. Don't ignore these symptoms! A $600-800 water pump replacement is much cheaper than the $3500+ head gasket job that can result from overheating. Another issue I've encountered is carbon buildup on the intake valves. Despite the dual injection system, some carbon accumulation is inevitable, especially if you do lots of short trips. If you're experiencing rough idle or hesitation around 2000-3000 RPM, this might be your culprit. A good Italian tune-up (driving at higher RPMs occasionally) can help, but sometimes professional walnut shell blasting is needed to restore performance. As for maintenance, I strongly recommend changing the oil every 5,000 miles with full synthetic 0W-20 - forget that 10,000-mile interval nonsense in the manual. The timing chain is designed to last the life of the engine, but I've seen them stretch past 150K miles, especially if oil changes were neglected. Listen for a slight rattle on cold starts that disappears once warm - that's your early warning sign. One maintenance item people often overlook is the transmission fluid. Lexus claims it's 'lifetime,' but that's marketing talk. I suggest a drain and fill (not a flush) every 60,000 miles. Use only Toyota WS fluid - I've seen aftermarket fluids cause shift issues. And while you're at it, change the engine air filter every 15,000-20,000 miles - it's an easy DIY job that takes 5 minutes and helps maintain proper air/fuel ratios. Trust me, these small investments pay off in the long run with these engines.