Oil Disappeared then Reappeared?

We just bought a Ford F-150 from a dealer about a week ago and they “inspected” it before selling. However, when my husband checked the oil it was empty. He bought oil and filled it then came home and when he looked again, the oil was overfilled. Yes, he made sure the dipstick was cool and tilted at an angle, he also let the car cool and checked it again. What is going on??

Some oil.today is so clear it is difficult to read the oil level on the dipstick. That’s my only thought.

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Or checking level too quickly after shutting engine down, so it did not have a chance to drain properly.

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You don’t mention the year/mileage.

But one thing that can cause this is the oil drain-back holes in the heads are partially restricted with sludge.

You could remove the valve covers to see if this is the case.


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If sludging is the case, it may be quite brutal and would likely be visible even through oil-fill hole.

So often it is a matter of eliminating the “impossible” to see what remains. So if no one snuck in and messed with the oil level, consider operator error, sludged up engine, or contamination from other fluids. I’m not sure if a dealer checking it out would have included checking the engine for sludge, previous owner’s maintenance schedule, or even oil consumption rate. Might want to investigate further.

This scenario does not surprise me one bit. Been there, done that (years ago)…

I guess it was a used vehicle of some model-year with some kind of engine in it, as these details have been overlooked.

Is this your first Ford F-150?

Assuming, as I did with the year and engine, that the vehicle was on level ground each time the oil level was checked, was the vehicle warm or at operating temperature when it was checked both times (before and after)?

Although Owner Manuals usually state that oil should be checked while engine is warm, as at a gas fill-up, I have owned vehicles (not sludge laden, clean as a whistle inside) where totally inaccurate readings would result by heeding that admonition.

Owner Manual or expert advice to the contrary, I always check all my vehicles’ engine oil level on flat ground when the engine is cold, as it is after sitting overnight (except on a twice per year 1,500 road dash to and from Florida where I read it at service station stops just to verify it’s still there).

Speaking strictly for myself (and I can and do verify the accuracy because I do all of my own oil changes, numbering in the hundreds and check drain volume by reusing oil jugs to facilitate recycling) always works and never delivers false readings. Just saying…

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If the truck has the 2.7 ecoboost engine, then the problem is not waiting long enough (at least 15 minutes) after shutting off the engine before checking the oill level. It does say this in the owners manual somewhere, but the manual is about 500 pages long. Anyway, I have to wait at least 15 minutes before I check the oil level. The longer you wait, the more accurate the dipstick will read.


A quick check on the web verifies what you say… 15 to 30 minutes, at least.

Like I say, overnight works for me on any vehicle I’ve owned.

Too bad that foxrl03_152812, when seeking help, didn’t give the most basic of information, besides Ford F-150. The model-year and engine description would be most helpful!

Perhaps "Them" will come back.

Perhaps "Them" will come back.

I think it’s a her and maybe doesn’t know what engine. You never know though.


Well, you could drain the oil and measure it

Something so simple, yet…
That could open another can of worms if this is an Ecoboost 2.7L. The oil needs to drain at least 15 minutes (warm) and then needs to sit 15 minutes if wanting to check afterwards.

Apparently, quick oil change artists botch oil changes on these and drastically over-fill them.


Good advice above, especially about waiting at least 15 minutes if the engine has been running before checking the oil level. It’s possible to make a mistake when checking the oil level too

  • first remove the dipstick completely, wipe it clean, then re-insert fully to the stop, wait 3 seconds, then pull it back out for inspection
  • look at both sides of the dipstick. the side that shows the lowest oil level is the correct answer.
  • freshly changed, very clean oil can be very difficult to see on the dipstick. run a fingernail along the dipstick from the middle towards the working end to tell if there’s oil there you aren’t seeing

Other less-likely ideas

  • the dipstick tube isn’t securely seated where it fits into the engine.
  • oil and coolant are exchanging back and forth inside the engine depending on temperature, etc (failed head gasket). If so the earlier this problem is correctly diagnosed the less expensive the fix will be. Look at the underside of the radiator cap. Notice anything unusual? Milky , cottage cheese looking ? A layer of oil floating on top of the coolant in the radiator?