I have a 95 F350 with the 7.3L PS in it. I was making a 600mile round trip that day and at one point I had the CEL come on. I pulled off to check under the hood and when I opened the hood a white thin smoke was coming from around the base of the turbo and the oil dipstick tube. I shut down and restarted the truck and that cleared the CEL. I didn't have any more problems from the light that day but checked under the hood a few more times on the trip and there was always smoke coming out unless I had already shut down the engine. I was just wondering if this was something I should have a dealer check or if it was something I could do, and if so what should I check.