If the eng. was 'cold', it was condensation(water). If it was 'hot', then I believe it was fuel(too rich) maybe mixed with a little oil

Dan

 

There is no way it is oil if your truck isnt at least smoking from the (said oil) burning in your exhaust.The chances of this oil blowing past everything without any other noticeable difference in running condition is extremely rare.Its prbally wayet/carbon mix