Mysterious case of increasing oil capacity 🤨

[Ford F834]

I’ve been changing oil in Ford truck straight six engines since the days of cardboard oil cans and church key can openers… always took 6 quarts with a new filter.

Today I changed the oil in my 81. Before I drained it I checked and the dip stick showed 1/2 qt low. I drained it, changed the filter and added 6 qts as usual. I started the engine, saw 50 psi on the mechanical oil gauge and it ran smooth and quiet. I went to confirm the level and nothing on the dip stick. Zip nada. I pulled the dipstick with it running and it was oily. Shut it off and checked again and it was bone dry. I added a 7th qt and it registered at “add”. I put in an 8th quart and it now reads “safe” but not completely full.

I see no leaks under the truck, coolant is full and has no sign of oil contamination. What gives? The drained oil fit into a 5 qt jug (typical). This one really has me baffled. I drove to Kingman and checked it again. Nice clean oil and just a bit below full level. Dipstick tube is secure and does not seem to have moved, dipstick fully seats in the tube. Mind blown. 🤯

[mat in tn]

this would cause me to question drainback. either in the rocker area or even the lifter area. but this would require a tremendous amount of crud .

[Gary Lewis]

Any chance that the dipstick has slid up into the handle?  Or that you got oil in liters?  (That's not enough to 'splain the difference, however.)

Or that you can't count?

STRANGE!

[grumpin]

My first thought was, as Gary said, wrong or bad dipstick.

[Ifitaintbroke]

I know a mechanic who worked on a 302 that happened to. It was run regularly but not allowed to warm up, and sludge clogged the drain back holes. Engine started knocking. When he pulled the valve covers, they were full to the top. Nothing in the pan.

[Gary Lewis]

The drainback idea is about the only thing I can think of that would do that.  But I'd think that overnight the oil held in the valve cover might make its way back to the pan, so I'd check the level in the morning to see.

And remember the problem that David/1986F150Six had when the crud let go in his truck.  It plugged the oil pickup and was starving the system of oil.

[Ford F834]

Drain back from the valve cover can’t be too bad… as I added the additional quarts I could hear the oil drizzling into the sump and the level change was more or less immediate on the dip stick. I do wonder if the same is true for the side gallery for the lifters?

I drove the truck almost 200 miles yesterday. I am picking up my flat bed trailer and truck parts stored at my dad’s place. It sounds normal, and the oil level hasn’t changed. I checked it again this morning. I was so puzzled yesterday that I almost drained it to measure the volume and check my sanity.

Garry, I question my counting and memory all the time…. I usually buy oil in 5 qt jugs and I thought shrink-flation might have reduced them to gallons, but they still say 5 qts. The first full jug should have at least registered on the dipstick.

That is a good thought that maybe the blade receded into the handle but it feels tight. I can’t intentionally move it. The oil is still honey colored. Hopefully my drive back to Golden Valley won’t be too much of an “adventure” 😬.

[mat in tn]

I think of this as I just recently took down a 300. the lifter area was so full of flaky layers of old cooked oil that I practically had to follow the pushrods to where they went into the crud. about as clogged as I have seen. when I dropped it off at the machine shop it went straight into the tank. it was no surprise that the cam was spalled and all lifters starting to mushroom. I tapped them out the bottom to avoid damage and put them right in the recycle bin.

[ArdWrknTrk]

Might you have bought a gallon jug, instead of 5 Qt?

I know that I like 5L, because every little bit helps.  😁

[viven44]

I always hope for the simplest issues. How does the dipstick tube attach to the oil pan on a 300 ? Threaded flare fit ? Or is it like a press fit ? Wondering if it’s popped out any

[1986F150Six]

Jonathan, when you checked the oil level just prior to the oil change, was the engine cold and had the truck been sitting overnight?

You had to add additional oil to obtain a "safe" level. Although not likely, perhaps the new oil jug  [5 quarts?] was not full and was not noticed. I would be tempted to drain all the oil into a clean container and measure the volume. Most likely, about 1 quart will remain in the filter.

Once filled with the correct amount and you feel comfortable with the dipstick reading, you might consider doing the following to calibrate the dipstick to your engine:

https://www.garysgaragemahal.com/#nabble-td37680

[Ford F834]

Thanks David, when I checked the oil before draining it the engine was cold and it had been sitting overnight. I do top off the oil from time to time as the engine is old and leaky so my only point of reference is the 5 qts that went from my drain pan back into the empty jug.

If I had a clean enough way to drain it and measure it I would have done that before leaving, but I didn’t. This is also the time of year for wind in the desert, making oil pours a messy and approximate process.

I guess I will probably just wait until my next change to see what my volume looks like. The oil level hasn’t changed and still looks clean.

The engine got quite a workout on the 200 miles home. It pulled the heavy trailer of truck parts up the mountain to Flagstaff at 7,000’ then back down to Golden valley. I drove in 2nd gear (27mph) and 3rd gear (45mph) pretty much the entire time. That load was a big ask for a F150/straight six. It was fine, just s-l-o-w…

[1986F150Six]

And the big six banger just smiled and asked, "is that all you have?"

[85pig]

This was mine before the hot tank:

[Gary Lewis]

Jonathan - That is REALLY a WORKOUT!  But I'll bet the 300 shrugged it off.

Chris - That is UGLY!  You can see why when it comes loose things get plugged up.  Right, David?

[Ford F834]

Yikes Chris, that’s gross! I don’t think mine has any of that, as I did replace the gaskets on the valve cover and lifter gallery when I bought it and they were decently clean… and I’ve driven it regularly and kept up with oil changes since…

Gary, David, the big six had no issues pulling the load it was just slow and happy. My only cause for sweaty palms was going downhill. The trailer brakes were barely doing anything and the F150 brakes get hot FAST with a load like that. Also the steering on that truck is pretty loose now, and rear weight does not help. Luckily I am able to just gear down… much appreciation for those close ratio gears of the diesel T19 🙂

[1986F150Six]

Gary Lewis wrote

Chris - That is UGLY!  You can see why when it comes loose things get plugged up.  Right, David?

Mine was no where near to that condition, but did cause a problem, so I am glad the engine in the photo was thoroughly cleaned.

[1986F150Six]

Ford F834 wrote

Gary, David, the big six had no issues pulling the load it was just slow and happy. 🙂

Ever wonder why the 302/5.0L was never offered in anything larger than the F250, but the 300/4.9L was offered as the base engine all the way up to the F600?

[ArdWrknTrk]

I don't question success.

We should all be mature enough to know why.

I had a '65 Powerwagon Mason dump with the venerable Dodge slant six.
That thing never needed to stop and rest, just like this here Burro.

Try that with some high strung througbred!

[viven44]

Just changed the oil on my 460 truck today. I have the opposite problem. Dipstick reads full at 5.5 quarts.