Mystery Machine
 

I own a 3.4l 2002 sr5. About two weeks ago i had an oil change and filled it up 5 quarts no problem. A few days after the oil change i went on a road trip-ended up putting around 1500miles on it, however during the middle of the trip when i checked the oil it was gone. Vanished didn't show a drop of oil on the dipstick, and this was only after about 800 miles of driving on the interstate after the oil change. Thinking the obvious i checked for oil leaks. Nothing. Checked for oil burning on the exhaust manifold. Nope. Did not smell any burning oil anywhere in the engine or near the exhaust. Moreover, i never get blueish smoke from the exhaust. So i drive to some oreilly 600 miles from home and grab a couple quarts of 10w-30 drop it in the engine, check the dipstick, and still not a single drop of oil. SO i grab THREE more quarts and come to find there was ZERO oil in my engine. I have absolutely no clue how i did not sieze during 800 miles of driving with no oil. Drive on the new oil for 250 miles or so, check dipstick, and what do you know its empty again. Someone please tell me how 5 quarts of oil vanishes from my engine in 250miles with no oil burning or leaks. Im beginning to develop a theory that 5vz fe's just don't even need oil, i mean hell i might as well drop whatever i want in the engine. Maybe it just needs some water or coolant in there.

That seems crazy and impossible. Maybe you didn't have the dipstick in all the way?!

That’s pretty odd and scary.

You would think it would show itself, it’s gotta be going somewhere.


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Curious how this will turn out.
Have you checked your coolant?

Have you popped your oil filler cap and taken a look inside?

Update/Help
 

Found the problem but don't know how to fix it. Somehow all my oil ended up in my air intake?! Took it off and it was all over the mass flow sensor, and inside my intake hoses. Turned the intake upside down and at least half a quart drained out. Cleaned it all up, and took a look at the spark plugs to see if any oil was getting past the piston rings, luckily they were fine, ended up replacing them anyways. i'll probably change the pcv pipe as well, but i'm just going by process of elimination at this point i really am at a loss for words, any advice is greatly appriciated. Here's some pics of the intake attached.

Dipstick was all the way in, confirmed this by putting 5 quarts in after i realized it was empty somehow and it showed up on the stick.

coolant is fine, no milky or anything, checked transmission fluid as well to see if somehow oil had gotten in there and it was clean.

I do know you can run them out of oil and the motor won't seize. I bought a 99 4runner 3.4L 139K mi with only 1 quart of oil in it, I put 5 quarts in and it just barely came out on the bottom of the dipstick at 5 quarts. So only had 1 quart i it. The motor had a broken oil sensor wire, so oil light would never come on. It was owned by a jackass that had no concept of oil.
I filled it up with oil, but basically the motor was junk at that point, I ran it another 30K til it started using 1 quart of oil per day. At 1st it was ok, but it progressively used more and more oil and started smoking. Then I swapped the motor.
Check your oil sensor and wire, the oil light should be coming on. Regardless, sounds like your motor is toast.

It's not possible to drive 500 miles without oil at highway speeds. Check whether you have the correct dipstic as I find people buy dipsticks online and ended up being incorrect item. I bought a dipstick for a hilux diesel on ebay and seller stated the correct engine. Guess what, it is about 1.5 inches shorter than the oem dipstick.

My engine is toast?? It just hit 100k. That can't be right. Everything else works great.

My take. If you ran it out of oil, some areas suffered from lack of proper lube. It may still run, but you had to have had some serious metal to metal friction.
It may act like mine did, it may run sorta ok driving it for awhile. But you'll see the damage by how much oil it uses now. The pistons/rings/bearings had to take a beating at say 5 quarts low for extended run and RPM.
I got 30K more after this on mine, I was amazed it never seized.

It sound like the last thing that you did before things went horribly wrong was an oil change which I assume included an oil filter. Could the new oil filter be faulty, plugged, or back flow valve stuck? I don't know what would happen if the oil pump cant push oil past the filter. Maybe the pressure would push the oil up and into the intake?

I think pretty much all automotive oil filters use a spring on the filter element. If the oil can't get through the filter element, pressure builds up until the spring allows oil to bypass the element. Theory (and it's a good one) being that dirty oil >>>>> no oil in terms of the engine surviving the next few minutes.

As far as I know, about the only way oil gets from the crankcase into the intake is via the PCV system, which allows crankcase pressure (blowby from the piston rings) to vent out of the valve covers, into tubing, and into the intake system, so the engine can burn it. For a MASSIVE amount of oil to go through the system I think it means that (and there are plenty of other possibilities):
- there is a LOT of blow-by - so much that it is interfering with the oils ability to drain from the valve cover area back into the block, and it eventually starts flowing out of the vents into the intake. This is supposed to be a fairly modest amount of air going that way.
- there is something blocking up the drains in the head that allow oil (from the valve train lubrication) to drain back into the block, and it builds up until the covers are 'full' and oil goes directly into the intake, intead of crankcase fumes. Gunk, or sealer, or... who knows what?

My theory:

You are somehow WAY overfilled on oil. The oil in the intake has been frothed by the crank and pushed out the crankcase ventilation system.

Don't drive the truck until you have this figured out. Drain the oil and see how much comes out... I think you will find you have a bunch of extra oil in there...

-Charlie

THIS^^^
Dipstick is misrouting or something if the truck is running fine with nothing showing on the dipstick. If you ran it out you'd know it.