Why would he do that

...I mean, what purpose could that possibly serve?

[/quote]Is this normal and OK to do this? [/quote]

No.

 

He did it so the smoke or steam wasn't coming out from under his truck and instead coming out the stack. I sort of thought that was obvious.

 

It is normal for a certain amount of crankcase gases (smoke, steam, whatever you want to call it) to come out of the breather tube. This problem is part of the '07 emissions for on-highway diesels, the '07 engines have a closed crankcase (no venting fumes).

If the gases are excessive... repair the problem. Actually, what he has done with the breather tube may actually compound the problem.

Under high exhaust flow, his crankcase will be under a high vaccuum

What SEEMS like a good repair... isn't always.

 

Hi, I have been reading through some of the history on the problems here and was wondering how things went in the end and if the problems were associated with the charge air cooler?
I work for a company that design and manufacture charge air coolers for large diesel engines called Vestas aircoil A/S in Denmark (www.vestas-aircoil.com), not so much truck engines but maybe they can advise if you have any problems.

They have a charge air cooler cleaning service facility in Denmark.

 

Have you done an oil sample on this engine?