I think I am going to stop doing oil changes in my truck.

It is burning almost a quart of oil every 100 miles, so in 3000 miles, I'm pouring enough oil in it to do 3 complete oil changes. I think I'm going to stop changing oil and just keep changing the oil filter every 3000 miles.

Anybody see any reason why I should even bother draining and replacing the oil? I'm sure it stays plenty stirred up enough to avoid anything settling in the bottom of the pan, and as long as I change the filter, it should keep the oil clean (or at least as clean as diesel oil gets anyway)...

 

30 qts between oil changes? If it was mine, I'd be investigating where the oil is going and fixing it. Does it burn off the first quart and tend to sit at that level, or will the level keep dropping?

I'm just about a quart low at the 3K mile mark. Most of that is going out of the drooling valve cover and front seal.

With that much oil going through it, it probably doesn't have much time to get dirty. But, there is the chance that the contaminants suspended in the oil aren't making it to the filter or out of the exhaust.

Jason

 

Cheeper, didn't you just replace the valve stem seals? This doesn't sound good.

 

how much do you drive the truck? At a quart every 100 miles it would be cheaper to buy a new truck.

 

I have been having a similar issue although not as severe with keeping oil in my truck ever since I had the valve stem seals replaced. I usually have to add 1-2 quarts in between oil changes at 3000 miles.

As far as investigating where it is going, the blue smoke on take off after the truck has been sitting idling for a minute or two is proof enough that it is being burned.

I have concluded the shop that did the replacement didn't have a clue what they were doing. Does anyone even know if these require a special tool? That was the only thing that kept me from doing it myself. I figure I will have to just go back in and do it myself like I should have in the first place anyway though...

-Dave

 

All you need is a valve spring compressor ($10-$20) and to bring the piston to TDC before removing the keepers on the cylinder you are working on. Its time consuming but not a difficult task.

 

I burn about a quart or two every 2000 miles, but since thats about all I put on my truck in a year I can live with that... With a quart every 100 miles thats a lot of oil. The fact that it's burning oil points to the valve seals or a leaky valve cover, rear seal.. Is it dripping onto the pavement?

When you don't burn oil with a worn diesel then its time to worry.... I remember a call into "Car Talk" where a grandfather, father, and son were driving a diesel truck... Grandfather was burning about 2 quarts per tankful, father was about even, and son was actually adding 2 quarts... Of course what was happening was diesel fuel was getting pushed past the rings and going into the oil... Actual oil consumption was highest (and probably accurate) with the grandfather because he was easy on the truck... Son on the other end was lead footing it and adding diesel oil into the crankcase which is not a great lubricant...

Then again, your engine could be so worn that you are actually pushing diesel oil into the crankase and also burning it... So, the longer you go, the crappier your oil is, even though you add new... But, is it worth an engine swap or rebuild....? A compression test might be a good idea... If the compression is high then it is probably the valve seals.

I have an old Allis Chalmers Bulldozer that burns about a quart an hour, some up the stack and some on the ground... But I only use it about 10 hours a year so it's not worth an engine rebuild... I do change it every 2 years because I don't want to throw a rod due to an oil failure.

David85, did you actually change the valve seals without removing the head?

 

mine burns maybe .5 quarts every 4000miles.
I'd say crankcase ventilation is THE most important part of oil consumption.

 

if it was me and it wasnt leaking real bad from anywere then i would pull the heads and check the cylinderwalls,

mine uses about a quart every 150-200 miles, but if i leave it a quart low then it dont use it as fast from then on

 

RCrawler - I have been trying to figure out where its going. I put an oil trap in and it is catching most of the blow-by vapor - very little oil appears to be going through the CDR and into the intake. CDR is nearly new and seems to work fine, valve stem seals are new, and it doesn't leak more than a few drops sitting in the driveway. The oil pressure is good - when warmed up its just under 20 psi at idle and 37 psi at highway speed. It starts just fine after a 7-10 second shot on the glowplugs. The compression isn't stellar, but it isn't too bad. Last time I measured it I got 320-360 psi with the engine dead cold. Unless it is pouring the oil out the exhaust side of the turbo bearing into the housing and out the exhaust pipe, I don't know where it could be going (though you'd think at lease SOME of it would make it back to the tailpipe if that was the case).

Dave 7.3 - you are correct - it does puff some blue smoke - especially after start up until it gets warmed up, after sitting idling, or when chugging around town at lower RPMs. Though you'd think it would be blowing clouds of smoke all the time with that kind of consumption. It seems to burn most of it pretty cleanly once its warmed up and running at decent RPMs.

David85 - yes I did just replace the valve stem seals - it made little or no difference in the oil consumption. It was a relatively easy job and only took me about 3 or 4 hours - so I didn't loose much by trying it.

serottak - buying Delo by the gallon its about $3 a quart - so the oil is costing me about 3 cents a mile. How far do you think that would go towards a new truck payment? I don't drive it more than 5k-10k a year so oil costs me $150-$300 a year. But even if I were driving it 20k a year that would only be $600 for oil. Not going to pay for a truck very fast at that rate.

redbug - There is no sign of fuel in the oil. It isn't thin and doesn't have a strong diesel odor. You can bet if there were I would notice as often as I'm checking it.

DeepRoots - there doesn't seem to be a crankcase venting issue. The hose from the filler neck, to the oil trap, and the hose from the oil trap to the CDR both seem to be venting a steady stream of crankcase vapor. CDR is almost new.

deyoung14 - leaving it a quart low seems to slow down the consumption a little bit - but not very much as far as I can tell. I haven't been filling it past the quart-low mark, and after 200 miles of driving the oil will be low enough that only the last 1/4"-1/2" of the dipstick actually dips into the oil. 2 quarts brings it back up to about 1 quart low, and its good to go for another couple of hundred miles.

Anybody out there with a 6.9 want to give me a measurement of the length of the dipstick in their motor? If so I'd like to know how long it is from the tip to the bottom of the yellow steel ring that caps the dipstick tube. Unless I have the wrong dipstick - and it is about an inch shorter than it should be - I'm pretty much out of ideas here...

 

29 9/16 thank you for that post, i was about 2 low...

 

If it was "2 quarts low" and dead cold, I hope you only added 1. When the engine is at operating temp the oil will expand enough to read almost a quart higher on the dipstick. If you added 2 quarts you probably overfilled it by nearly a quart.

You probably already knew that, but it is info that needs to be repeated frequently...

 

If you are dripping a few drops in the driveway, what are you dripping when the engine is running and pumping oil through the system? I remember a 6 cylinder chevy my friend had, it dripped oil about once ever second from the main seal while running at an idle.... boy did that go through some oil.


CheeperJeaper, good thought on the oil level. Oil does expand when warm, thats when you never see snowflakes on a heating oil truck, they like to keep the oil heated in a garage.... Didn't think about that in my 6.9, I will start checking my oil when warm.

 

i have been told my while life by the mechanics in the fam to check the oil when it is dead cold and not yet been cranked that day. that it gives you the truest reading on oil level...

 

True...
IF the dipstick is calibrated to read the oil when cold. From what I've read, the owners manual for these trucks says to get the engine up to full operating temp, shut it off, let it sit and drain for 10 minutes, THEN check the oil level...
Most engines don't have 10+ quarts of oil in them so expansion of the fluid as it gets hot isn't as big of a factor. In an engine that holds 5 quarts the expansion would only be about a half a quart.