93 with a lot of blowby

[Firefarm]

My 93 K3500 has 163000 miles and is starting to get guite a bit of blowby out of the vent in the valve cover. I should also add that it has been getting progressivly harder to start in the last couple of months. Have I finally succeeded in killing my engine? Once it does start, it runs like a champ, 40+ lbs of oil pressure, and only uses about a quart of oil in 3000 miles with some oil leaks...

[whatnot]

Vent in valve cover?
Is the CDR valve missing? The blowby is supposed to be routed through the CDR to the aircleaner box so you never see the smoke.

[Firefarm]

The previous owner had routed a hose from the CDR to the ground and bypassed running it back into the intake.

[john8662]

How much smoke are you seeing? There is supposed to be some, all engines have some blow-by. Its bad blow by when you can see the oil dipstick tube steaming with blow-by on a factory system (unvented). I know on my 6.5 once hot I can remove the tube going into the turbo boot while running and I get a steady stream of blow-by, not real dark, but its really coming out of there. My test for blow-by is always just open the oil filler tube while running, if just a little blow-by comes out, your generally dealing with a low blow-by engine. If it comes out in plumes, then its worn.

My advise, I would get all the necessary hardware to put the system back the way it was from factory. You won't hurt performance one bit, its actually better that the engine burn the blow-by rather than venting oily vapors into clean air. The oil usage you describe is normal for that many miles, or even a 6.5 being worked hard pulling or just in general. One quart in 3k miles is doing quite well. Its the 1 quart per 500 miles or every tank of fuel that gets excessive.

Check some of the other components of the engine, how are the glow plugs? How many miles are on the injection pump and injectors? Have you had your timing set, or is it still factory timing? How fast is your starter turning over the engine, slow starter won't start well at all. Good batteries, these engines need good batteries to turn over the starter well. Things to consider besides just compression or engine wear.