Black dawg
Registered User
Have had many of these over the years that burned huge amounts of oil, but never really tried to fix one. Anybody tore down a major oil consumer, and what did you find?
6.9 7.3 oil consumption?
- Thread starter Black dawg
- Start date
Most have found oil consumption issues to be because of a malfunctioning CDR valve. Mine got stuck shut for a while, and you could really hear it trying to diesel on when decelerating. Also burnt through a gallon of oil.
Another large contributor could be a broken piston ring. Had an engine that had a broken #7, but ran and drove just fine. Drank a gallon of oil in 200 miles though. If you're trying to find the health of your engine, compression and leak down tests will tell you a lot.
Another large contributor could be a broken piston ring. Had an engine that had a broken #7, but ran and drove just fine. Drank a gallon of oil in 200 miles though. If you're trying to find the health of your engine, compression and leak down tests will tell you a lot.
Jesus Freak
Full Access Member
My turbo IDI had melted pistons making it drink oil. And my original 6.9 had a bad piston that made it drink oil. Those are both "unnatural", so I don't know what a typical oil consumption would look like. The na 6.9 in my tow truck doesn't appear to be radically consuming oil......... except the oil I run it on.
Kevin 007
Full-floater
Ya I have torn a couple down. I always check/replace/clean/re-route the CDR first. I have never actually remedied a consumption issues with any CDR valve work.
Usually see a broken ring or a few, melted ring lands from excessive EGT. The rings probably break from excess starting fluid use, etc. Valve seals are usually deteriorated which also contributes but I don't think they are the cause of the MAJOR consumption that some of these engines have.
Then I see some engines with extreme high mileage, and been worked hard, but never abused as in run with excessive egts for any length of time, no improper ether use, no 4000rpm gov springs, no turbo, etc, and they are not using much oil at all so the rings/pistons are probably in good shape still.
Also, I rarely see a turbo engine (factory turbo or otherwise) reach really high mileage without burning large amount of oil, or even still running at all. They just don't seem to last when turbo'd. Just sayin...
Im not a high hp guy, and just drive and work them lots. low speed, low expectation in performance, but high expectations in longevity and reliability. And running within their parameters, I achieve that.
Usually see a broken ring or a few, melted ring lands from excessive EGT. The rings probably break from excess starting fluid use, etc. Valve seals are usually deteriorated which also contributes but I don't think they are the cause of the MAJOR consumption that some of these engines have.
Then I see some engines with extreme high mileage, and been worked hard, but never abused as in run with excessive egts for any length of time, no improper ether use, no 4000rpm gov springs, no turbo, etc, and they are not using much oil at all so the rings/pistons are probably in good shape still.
Also, I rarely see a turbo engine (factory turbo or otherwise) reach really high mileage without burning large amount of oil, or even still running at all. They just don't seem to last when turbo'd. Just sayin...
Im not a high hp guy, and just drive and work them lots. low speed, low expectation in performance, but high expectations in longevity and reliability. And running within their parameters, I achieve that.
Black dawg
Registered User
I have seen the same as far as turboed engines almost always end up being major oil consumers. Have seen a few high mile ones that didnt, but fuel rate and boost was pretty much like factory turbo calibration.
The engine I am thinking about is in my personal pickup, been driving it for 20 years and about 250k. currently just short of 400k.......if the original owner was being honest about miles when I bought it.......
It has been inconsistent with oil consumption for a long time now. I can go 1000 miles towing and not need to add any, or 500 just driving around and need a quart....or a gallon???? It has been turboed and intercooled, and worked. Egt has never been a problem, but coolant temps have been for sure.
The engine I am thinking about is in my personal pickup, been driving it for 20 years and about 250k. currently just short of 400k.......if the original owner was being honest about miles when I bought it.......
It has been inconsistent with oil consumption for a long time now. I can go 1000 miles towing and not need to add any, or 500 just driving around and need a quart....or a gallon???? It has been turboed and intercooled, and worked. Egt has never been a problem, but coolant temps have been for sure.
Kevin 007
Full-floater
Inconsistency is interesting. Turbo seals maybe?
hacked89
Full Access Member
Did you notice oil in the cold side charge pipe? The pedestal drain is where the cdr was previously and I believe the turbo puts the air under light vacuum which pulls oil mist through the cold side. This doesn’t occur as significantly in an NA motor you will just see a light oil mist to none going into the intake via the cdr.
Non-intercooled you wouldn’t notice it besides oil consumption because it’s just shoving it back in the same place.
WrenchWhore
Full Access Member
I've had a similar situation. Drive it short distances like to and from the grocery store/grab beer (doesn't really get up to temp) seems to black/burn more oil. Almost 3-4 quarts in only a few hundred miles one time. Then i'll tow mild for a few hundred miles and no real change in oil usage. I'm wondering if it has something to do with an older high mileage motor needing more time/heat in the engine to fully expand and "seal up"?
ISPKI
Welding/metallurgical engineer/Metalsmith
That is especially common with turbo charged engines. I have the unfortunate situation of having 2 DDs that are both turbo charged and my commute is about 3 miles. Both vehicles contaminate their oil and start consuming some within 3k miles despite using top of the line amsoil oils. My volvo will hardly change on the dipstick until right around 3k, then it starts slowly consuming. Gets worse the longer it goes without changing the oil. I usually end up adding 1-2 full quarts by 5k, not alot by comparison to older trucks but that is significant for a 2012+ vehicle. Also has an intermittent CEL for the catalytic converter, probably getting painted with oil vapors and not burning it off during my short drives. My mazdaspeed does the same thing with the added bonus of venting through the turbo seals as well.
On the flip side, I will take the volvo on a 1000+ mile family vacation up through northern maine and the oil doesnt move at all on the dipstick.
Black dawg
Registered User
There is oil in the intercooler tubing and intercooler, but I do have crank vented to the tubing just before the turbo, and with lots of blowby I always blamed it on that.
I have noticed that very slight vacuum in the intake, I guess it could be pulling some oil in through the turbo at idle and decel?
I was thinking about that, or valve stem seals. This weekend it idled while I was working (probably and hour) and when I started to drive there was a pretty impressive trail of oil smoke that eventually cleared up.
hacked89
Full Access Member
Exactly so when I have mine idling or timing for extended periods I notice it, but it doesn’t mean the turbo seals are bad I’ll see this on a freshly rebuilt turbo.
Jesus Freak
Full Access Member
I thought that was from incomplete burn of the fuel because it's just idling.
hacked89
Full Access Member
I can take this one too, of course it doesn’t mean this is always the reason but most common reason. You can run an IDI to spec with no exhaust valve seals, except it will smoke initially. The plastic becomes very brittle. One set of heads I put together with no exhaust seals the current one in the truck I put exhaust seals but mostly for fun. The cool thing is I have clear exhaust at idle which is nice considering a 140+cc pump and 10.2 degees of timing. Not that the pump and degrees play much into it at idle but you get the idea. I’ve seen exhaust valves seals no where to be found except a fragment left behind, taken into the great beyond. Honestly not even sure how that happened so cleanly on 8 cylinders.
Jesus Freak
Full Access Member
Clear exhaust after idling an hour and still clear exhaust when you drive off after that much extended idling?
Black dawg
Registered User
yes, typically dont have issues with that even near zero degrees out. IDI diesels with good injectors and enough timing almost never will show any fuel related smoke.
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