Discussion in '6.9L IH & 7.3L IDI Diesels' started by aofarrell2, Oct 7, 2019.
For my IDI, I used to run Conventional 15W-40 Delo and had to add 1/2 to 1 1/4 Quarts every other day. But then I decided to give the Full Synthetic 15W-40 T6 Rotella a chance on the last oil change and its been TWO months with only a Quart of Oil added and the color is practically Still clear!!!, per oil change $$$$ more, but definitely Worth it.
Man you all have some thirsty trucks. A gallon every few hundred miles is insane.
I'd guess some combination of valve stem seals and piston rings.
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I don’t mean to sound pessimistic. That’s just been my experience with my truck. You never know what the problem could be. Could be oil weight or the CDR. Or any combination of issues. To me, figuring out what’s wrong with it is part of the experience. I’ve tried everything under the sun with mine. I’m left with rebuilding it. It has a rebuild on it already but I don’t know what kind of workmanship went into the last rebuild. I could even have a N/A block in mine. They supposedly replaced the block when they did the rebuild. I wouldn’t put it past the mechanic who worked on it before I got it. Long story but my truck sat in a pasture for 6 years after it was last rebuilt because it had a bad turbo and my dad didn’t have the money to get it fixed.
I would run a compression test on it if changing the oil weight and cleaning or replacing the CDR doesn’t fix the issue. Correct me if I’m wrong but I believe we should have about 400 psi in these engines. I had under 200 in 5 cylinders. Even put a couple squirts of oil in them and checked it again. No change. My issue is probably valve stem seals. I plan to pull the heads off and do a check on the rings and cylinder walls before going any further.
How about injector seals I had my 7.3 go 8 quarts low then shut off under warranty they replaced the seals but damage was done lemon law! bought new truck
That would have been on a Powerstroke. Our IDI engines don't have oil going through the injectors.
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