I recently bought an xterra and I have a few concerns. It's a 2006 4wd. I bought the x from a local small dealer, it was as is with no warranty, and of course I got the "runs perfectly" speech. The day after I bought it it started to overheat and lost a lot of coolant, so I had it checked out, they said it was an air bubble in the heater core so they purged it. A few days later it began getting hot again, so I took it somewhere else and they changed the thermostat , so far it's working well however it still reads hotter than I noticed in my old car, it gets just above the temp icon. Is this a normal running temp. Also, I can hear what sounds like coolant moving through the system. It isn't boiling, I heard the bowling before I changed the thermostat, it sound more like gurgling when stopped and when I turn it off. It also sounds like the coolant is rushing through the system when I accelerate sometimes. Another thing I've noticed is that when I am going downhill or not actively using the accelerator the rpms go up, almost like its shifting. There is also a small leak of what I think is oil, it's a very small and slow drip. Lastly, ok not sure if this is even a real issue but the engine sounds "Whiney?" Almost like the sound that's made when the power steering is low, however it does r make the sound just when I'm turning, it also gets louder (maybe a little higher pitch) when accelerating. One more thing, sorry, when the slip control kicks in, there is an unsettling grinding noise. I don't know if any of this is related or if its even an issue. I'm just very paranoid, also I'm broke.