The 1grfe really is "bullet proof" it seems

I'm dumb and forgot to put my oil cap back on after changing the oil. Then I drove 150 miles to the beach and back. It did not even spit out a drop of oil from then filler neck. Put the cap back on, which I found wedged in the engine bay and continued on my merry way. Oil looked good as new when I inspected it. Drives perfect.

 

It's not just the 4R. I had the same thing happen to me with one of my Tundras (5.7l)..... went a full 4k miles between oil changes without a cap. Never spilled or spit a drop of oil the whole time, never threw a check engine light. Nothing. I couldn't believe it.

 

They do have abnormally long filler necks I've noticed. The fill hole does not sit right on the block such as some other engines.

 

place the oil cap on the hood latch, a simple way to keep from forgetting to put it back on. The hood wont close.

 

it is not a dumb-proof

 

If anything it would have thrown a CEL but yeah you are fine.

 

So you missed an opportunity to upgrade to a TRD oil cap?

 

My wife's 21 Corolla SE with 30k miles has quite a bit of pressure spitting out oil when I remove the engine oil fill cap when it's running. My 4Runner with 45K has nothing.

A bit of an old school trick to check for excessive blow by or a bad PCV. But I was surprised last time I changed oil and checked this.

Video to show an extreme example:
https://www.youtube.com/watch?v=qzY8jwnC_Ow

 

excessive blow by Corolla has due to carbon build up at piston rings area (at best), or wear out pistons/cylinder walls (worst) due to low quality oil and high interval of oil changes. 4Runner at Tahari plant in Japan, filled with Toyota Genuine Motor Oil 0W20 with incredible high level of Molybdenium to survive 10K miles oil change interval. you may try to save Corolla by cleaning carbon (various methods may used). But soon all engine gaskets on Corolla engine will start leaking oil pushed out by blow-by gases.

 

Had an '82 Celica that I drove from Wis. to Tenn. without the oil cap. Found it on a x-member. The 22R was still going strong at 167,000 when I sold it. Never burned any oil.

 

Amazing.

Engine is under vacuum so it shouldn't spew out oil from the oil cap... it's not like you took off your oil drain screw and then drove around for 2 mins..

 

The top end is under vacuum. The bottom end is often under pressure due to a small amount of blow by. This is why we have pcv (positive crank case ventilation) systems in place. Too much pressure can blow seals and do damage.

If there is not a lot of pressure coming from the oil fill cap, it’s because you have healthy pistons, rings and cylinders.

A little blow by is normal, but too much can cause problems. Especially if your PCV fails.

 

Left the oil cap loose on my VW Bug and it blew off many years ago. Damn thing caught fire and burned up
on the freeway. Stupid me!