97 Cummins 5.9 12v heavy smoke under load

[Arvik]

Never smoked at all even on cold start, over last 1k miles started to notice small amount light blue smoke, now..
Parked and sat for a week, now when I put the rig under load there is lack of power and lots of light blue and white smoke. Only under load though. While at idle there is light blue smoke , but under load it's is like fog machine at the Disco.
While in neutral I can pull 2k rpm with only light smoke. If I put it in drive then the smoke show starts.
Only have 149k miles just did oil change and filters. Only other clue maybe would be the oil pressure gauge has been acting funky showing higher than usual pressure then suddenly falling back into normal range.
Thoughts?

[CHEESE_WAGON]

Blue is oil, white is coolant. Neither sounds good. Head gasket possible. Remote possibility of turbo seals, but that's usually blue smoke only. Oil pressure fluctation isn't good either, sign of a failing oil pump or possible bearing problems. Worst case scenario, you could be looking at engine replacement / overhaul.

Some older light duty automatics had a tendency to suck trans fluid through the modulator if so equipped, this would cause similar smoking to what you are experiencing. Not sure if your trans has one or not, as diesels do not generate vacuum for a typical vacuum modulator, but another possibility. It wouldn't have anything to do with oil pressure fluctuation though. Gauge is is a possible bad sending unit or wiring problem, but I doubt it, not that common.

Injector failures have been known to cause white smoke, but not blue that I'm aware. Might try some fuel additive to see if it helps?

[bus-bro]

Yes, light blue smoke is lube oil. White smoke can also be from a failed injector, or low compression, and the pumping out of unburned fuel. Regardless, unburned fuel can wash the lubricating oil off a cylinder liner's surface and cause liner failure and light blue smoke. Light blue smoke by itself might be from a broken oil ring. Black smoke is from an over-fueled situation. Not enough oxygen to burn it all the way down.

You can also get as sense of it by smelling the exhaust, which ain't
recommended. But if it smells like diesel, that's raw fuel. If it's like coolant, it's coolant.

[Arvik]

Thanks for the reply 👊 .
Can't wrap my head around why only smoke heavy when under load. Wastegate stuck? Would that cause same symptoms?
Best way to check turbo seals?

[Ronnie]

So under load meaning just sitting there in drive brakes set? What happens when you actually drive it? Does it clear up and stay that way or keep making smoke?

[Arvik]

I've moved it prolly 40-50ft up then down small hill in driveway. Haven't dared take it out further because didn't want to risk hurting engine further.

[banman]

Check for coolant in the oil!
Remove the oil fill cap and look for 'milkshake' like froth inside the valve cover and dipstick.

Check for oil in the coolant!
Is there an oily sheen on the coolant? Get an "exhaust sniffer" test kit. It detects CO in the coolant -- if present you have a headgasket failure (or wet-sleeve failure? I'm not familiar with wet-sleeve internals...)

[Brad_SwiftFur]

Originally Posted by banman

Check for coolant in the oil!
Remove the oil fill cap and look for 'milkshake' like froth inside the valve cover and dipstick.

Check for oil in the coolant!
Is there an oily sheen on the coolant? Get an "exhaust sniffer" test kit. It detects CO in the coolant -- if present you have a headgasket failure (or wet-sleeve failure? I'm not familiar with wet-sleeve internals...)

Correct me if I'm mistaken but the OP indicates a 5.9 Cummins which is not a sleeved engine.

[Ronnie]

Originally Posted by Brad_SwiftFur

Correct me if I'm mistaken but the OP indicates a 5.9 Cummins which is not a sleeved engine.

Correct not a wet sleeve engine.

[Arvik]

No oil in antifreeze or antifreeze in oil.
No it's not sleeved.
What does a fukd wastegate valve do for symptoms?