Engine oil is missing and it has no leaks undeneath it
I did an oil change cause I checked deep stick and found no oil so I put new oil and filter, I didn't think anything bad cause is not overheating, about 3 weeks later I checked again and there was no oil or signs of water, I looked for leaks couldn't find any it was completely dry, I checked the water reservoir and it look kind of brown and it felt like oily, that's any one know what might be the problem? is been like that for few months and it has never overheated at all.
2007 F-150 58000 miles
