I am looking at used trucks and am asking what should I be looking for as far as clues to tell me the condition of the 12 valve 6 cyl 1994-1999. With out a compression test, could I look for oil blow-by?
Thanks

 

the 12 valves ran up as far as 98, half way through the year the head was redesigned for 24 valves, all for emissions reasons.

anyway, for a 12 valve, as long as the idle is smooth(for the most part) no excessive white or black smoke, and oil not leaking from the valve covers(easy fix but could be signs of a larger problem), you should be good.