Just bought a 2003 3500 Silverado with LB7 Duramax. Noticed after several days the pick up smokes and has a lot of blow by. The pickup is making oil and losing water. I did the oil from dipstick to white towel test and it doesn't seem like there is any fuel in the oil, but the pick up loses oil pressure after you drive it. I did a compression test with results as follows:

1 - 410, 3 - 400, 5 - 350, 7 - 150, 2 - 410, 4 - 410, 6 - 410, 8 - 410

I feel safe to say it has a blown head gasket, but does anybody have an explanation as to why I would be losing oil pressure when I don't see water or diesel on the dipstick. The pick up does not run hot and starts right up. I'd appreciate any help. Thanks

 

how meany miles are on it?

 

It has 252000

 

hummm kinda sounds like injectors all but the blow by im not sure about that could be head gaskets or egged shaped bores and worn rings. the oil pressure dropping can happen from thin oil from fuel in the oil from injectors leaking into the crank case.

a few more things id like to ask what does the smoke smell like?
how fast does it make oil?
how fast is it losing water and is it leaking out or burning it?

 

The smoke smells like diesel, I drove it about 100 miles and the dip stick is almost 2 quarts over full. The water is dripping on the ground at the back of the motor on the drivers side. (same side as low compression)

 

sounds like injectors and a head gasket is the colent resavor discolored or black at the bottom? that is a sign of a blow head gasket. thats just my thoughts dont take what i say as a for sure answer

 

Yes, there is an oil film in the coolant. Thanks for all the information. I guess after turkey day is over with I will get started pulling the head to see what is going on.Thanks again

 

if i were you i would replace both head gaskets and the injectors while you have it down its a hard job i just got mine put back together i can not say it enough take plenty of pictures its soooo helpful

 

will do thanks

 

no problem i hope yours goes better then mines going