Ok im down 1 qt. It's halfway between full and add. Took 1000 miles. We will see how long it takes to get to the add mark. I do run it pretty hard. 75mph is 3000 rpm and thats where I run it on the fwy.

Reading around on the net it's not uncommon for the 6.9 to use some oil especially if worked hard. Some people say that the valve stem seals are the cause. I'm thinking of putting in 2 qts of high milage oil when it gets 2 qts low and seeing if that improves it any.

I'm wondering if a higher-quality lube will resist and burn-off better, or if it cleans deposits and lets the rings seal better.

Are you checking the level at the same time and place? The diff between 5mins after shutting down and and checking in the morning after sitting could be up to 1/2 qt. Checking on uneven ground can do that too.

A quart in 800 is not great but here are some tips:

1) Check your CDR valve (Crankcase Depression Regulator), which functions as a crankcase ventilation device and when inoperative, will cause the engine to consume more oil. The CDR is designed to separate the liquid oil from the crankcase blowby gasses and returns the oil to the engine. The CDR mounts to the back of the intake manifold. If you see a lot of oil in the intake, it's probably a bad CDR, though sometimes it just gums up. Mine has just failed for the first time since new.

2) Don't top off with this engine. When it reaches the add mark, it takes two quarts to bring it up to the full mark. When it reaches that point, only add one quart. That upper quart will burn off quickly but the second one much more slowly. Been doing this with mine since I was given that tip by a fellow Ford tech back in the '80s.

Over the 25 years I've owned 6.9L, it has used oil... no matter what oil... in regular amounts. You can safely say they were designed to use some oil. I've used both Delo and Rotella, both 15W40 and 10W30 and there is no significant difference in the amount used. I even had some 15W40 Royal Purple in there for one OCI and it even slurped some of that. I think you will find the same with the Tection.


Here is something from an old Ford TSB:

ENGINE OIL LEVEL CHECKING PROCEDURE for LIGHT TRUCK 1983-86 E AND F SERIES TSB:

In order to measure engine oil levels consistently and accurately, it is useful to employ the following recommendations:

Park vehicle on level surface. Low oil level readings will be obtained if the vehicle is sloped away from the dipstick.

Have engine at normal operating temperature as oil expands at the rate of one percent per 25~F (14~C) change and the dipstick is calibrated to the engine at normal operating temperature. In addition, allow at least a fifteen (15) minute engine shutdown period to assure that oil contained in the upper parts of the engine has returned to the oil pan.

Have dipstick loop directed inboard as this eases installation and minimizes wiping action on oil level gauge.

Read oil level on both sides of gauge and use highest level (reading) for the actual engine oil level.