I'm gonna go ahead and step out there and ask. What is the main cause of blowby on a 12 valve? My rig has ALOT of miles, but still pulls hard and does'nt seem to be burning oil. But there is alot of blow by, especially after it idles for a minute or two. Just wondering. Go ahead and let me have it.

 

I'm thinking vacuum leak.

 

If it's not burning more than a quart of oil every 1000 miles don't worry about it.
What you are seeing could very well be steam from condensation in the engine burning off.

 

What's a LOT of miles 1 mil? I've got 300k and that's nothing really. This truck went well over a year and probably 30k or more without an oil change when my parents had it. I have a little vapor out of the breather tube at idle and it looks like a little grey smoke mixed with the black when I stomp on it and even some grey when I start it cold, but I now change the oil every 3k with Rotella and still never need to add between changes.

 

440,000 on my 94. I wouldn't even dream about blow by at anything less than 500,000 miles, unless the truck was hammered on a lot with out letting it warm up properly. Those 12 valves are TUFF. Just being a cummins engine alone it saying alot. One guy one here has almost 750,000 on his gen one, and his truck is heavily bombed. How are you determining that you have blow bye?

 

mine has 430,000, Hey Bill, after it's been running awhile could there still be condensation in the engine?

 

After up to operating temp, after .5hr, there shouldn't be.

I bet you are seeing oil vapor, as I do, but without oil consumption.

 

It depends.
If you do a lot of short trips moisture can build up in the crankcase and could take getting the engine good a warmed up for at least an hour before it's burned off.

 

i have seen several dodges over a million they just roll around and then u got a brand new truck again lol