C15 issues? Please help!
 

Hey everybody I'm not sure if this is where I should be posting this if not please let me know...ok so I'm new to the site ..also kind of new to the trucking industry I have a excavating logging and demo biz...so trucks kinda come with the territory...I baught an 06 western star with a C15 a year ago seems to run great ..."to a guy that doesn't drive truck much haaa"but ever since i got it it has had excessive Blow by... it also seems to make coolant disappear "seems to be out exhaust?"it has 240,000 miles on it now.. I took it to cat and the first thing he said was okay it's turned up to a 5:50 and you need a new motor for 30-some thousand bucks!? As I drove away sick..yelling out the window that rebuild better come with multiple ..easy on the eyes mail order brides that will s*** and f*** me the whole life expectancy of the rebuild!..... that was about 10,000 miles ago and it still plugs along it does what it's supposed to with no major issues it seems as though Im able to pass everything but a fuel station again I got used to it now but I feel like I need more power and I feel like the fuel mileage is horrible... I know I'm a little all over the place but #1can anybody tell me if I could turn this thing up over 550 ... and #2does anybody know what my problem could be with the blow by? I feel like It can't be the motor is smoked with 240k and cuz it just runs great all the time?

The blow by is your engines compression (think horse power) leaking past the piston rings into the crankcase because they are worn or stuck. Your MPG and power is suffering because of the blow by. Turning the truck up more would just give you worse MPG. Short of an in frame (cyl. liners rings ectra) changing the oil to a thicker viscosity might help. Your probably already using 15w40 so toss in a gallon or two of straight 30w.

You also mentioned the coolant, that could be because of a head gasket or cracked head. On second thought a head problem could also cause the blow by if it cracked in the right place, try the 30w oil and see if it improves any, if so its wear and tear if not its a crack either way plan on a rebuild.