Ok so as most of you know I just purchase a 2002 F-250 7.3L with 105.500 miles on it. When I first test drove it it had no blow by. I drove for about 15min to warm it up and when I got back to the owners house I took the oil cap off and there was not blow by, no white smoke. I could also not feel any air going in or out but it was a little windy so I don't know how accurate that is. Today, after I changed my fuel filter back to the ford one(I had a leaky napa one) I drove it back to work parked it and out of curiosity I took the oil cap off and there was white blow by smoke. Not a lot but some. I changed the oil to 5-40 Rotella synthetic 3 days ago as well as the coolant, trans fluid and 4X4 diff. My questions are; can using a regular or synthetic oil effect how much blow by occurs and can parking it on an incline change how little or how much blow by occurs. When I first checked it at the owners house the truck was at an incline up, as most driveways do that. My work parking lot its flat. Also what causes blow by. I searched and could not find what I was looking for so if there is a thread that i missed I am sorry. Thanks again all for the support and the answers to my many endless questions!

 

I can answer a little bit of this for you. Blow by is caused by compression leaking by the rings or intake valves and guides and getting into the crankcase. Very unlikely to be the valves as the truck would run like crap if you had valves leaking that badly. A little bit of blow by is normal at 100k plus miles. You've not really said how much. Also, if you went from 15w40 to 5w40 that may explain a little bit of the reason for the blow by just showing up now. Do not think parking on an incline of any kind will affect blow by.

 

little bit of blowby normal. Moniter it. Here is a reference. This is normal blowby Courtesy of Dan. when it blows smoke rings up into the hood, that means you have a dead hole. Smooth like the vid is normal. click here= YouTube - Ford Powerstroke Blow By

Bad blow by= http://www.youtube.com/watch?v=aEwqp...eature=related. the chugging smoke is from the dead hole.

 

I don't think you have anything to worry about. Wind conditions and the time of day (angle of the sun) also play a role in how bad the smoke looks. I've been playing with a few different kinds of dino oil, and my truck smokes a different amount with each brand of oil.

Oddly enough, the oil that smoked the most came back with excellent results when I had a lab do an oil analysis (OA or UOA). A little smoke is nothing to worry about, but it sounds like you might need to plan on a rebuild in another 500,000 miles or so.

 

lol, I hope by then I would have put a new built engine in it.

Thanks for all the replies, now I know how its produced and the different kinds of oil thing is interesting too.

 

Thanks for posting the link.
And for the record, when I made that video the oil in the crankcase was dino based Mobil Delvac 1300 Super 15-40 with less than 1000 miles since the last oil change.

 

Was your engine hot when you made that vid?

 

I don't remember that one.
Most likely it was halfway warmed up.