I will try to explain this the best i can. A couple of weeks ago I changed my oil. When i was finished i started up my car and let it run. It started making a clicking noise and i shut off the engine. I started it again and it still made the clicking so I shut if off and left it for a day. Well when i went back to it and started it the next day it was fine. I drove it for about fifteen minutes and it started clicking again so it doesnt do it all of the time. It makes the noise up until about 1500 rpm and when i go higher then that it stops clicking. What could this be? I also notice that my exhaust is spitting out some water.