Our diesel is using oil

[june19003]

Diesel Mechanics please help:
We have a 2003 Monaco Knight with a Cummins 8.3 motor. It has only 57,000 miles on it. We went on a 500 mile trip then found it was low on oil. (My husband said he had checked it prior to leaving.) We put 2 gallons of oil in it and took it to the shop. They found that the oil bypass valve was stuck. They replace it, hopefully was fixed, went on another short trip and on checking it found that it was low on oil. Any ideas what could be wrong. Thank you

[june19003]

Thanks guys, ya'll are awesome. Will check each of these things. Again thanks so much.

[dons2346]

Have you calibrated the dipstick? Depending on the installation, the dipstick can say you are low on oil but still be fine.

Find out how much oil the engine is supposed to have. The 8.3 motor should have either 20 or 22 quarts max. Drain the oil, install a new filter and measure how much oil you put in the new filter before installation. Then put the rest of the oil in the motor to make either the 20 or 22 quarts. Look at the dipstick and see where the oil line comes to. That is your new full mark

[ScottG]

I would also check the air/oil separator (sometimes called a crankcase breather) for the draft tube and check the draft tube itself for obstruction. If either is clogged, it will create back pressure in the crankcase resulting in oil going past the rings.

[fj12ryder]

It's down a couple gallons and "No smoke"? That seems very unusual. I'd take it out with someone following me and run through a variety of conditions and see if there's any smoke.

[alaska_dennis]

Check for an air restriction

dennis

[june19003]

Thanks Scott and Mike, my husband says the shop checked the turbo seals and there was no residue on the turbo, and there hasn't been any smoke, no oil on the engine or dripping. He hasn't checked the antifreeze yet. Any other ideas. The shop tells my husband, that it just "needs to be drove". Thank you so much guys.

[Mike_LeClair]

Are there any external signs of an oil consumption problem such as exhaust smoke, oil staining the motor or dripping on the ground, oil entering the antifreeze and contaminating it and any unusual motor noises? Scott could be spot on already with his suggestion of turbo seals so be sure to check that out as well.

Cheers!

Mike

[ScottG]

Turbo seals. Look for residue on impeller.