Low engine oil

Thank you for this post, it helped me figure out what was wrong with my car.
It was critically low on oil. I put some in and immediately the light stopped coming on.

 

this also happened to me. I thought I did something wrong when I replaced 2 modules on my hybrid battery. No codes at all and then when I checked the dipstick it's at the lowest level. Put some oil and RTOD is gone, crazy that Prius didn't even put in a low engine oil warning on the dash. For some cars once you see the low oil level warning, engine is toast already.

 

I don't know what the OP means exactly by "bone dry" but if you still have oil registering on the dipstick it will not flash the MWL. At the L mark on the dipstick you still have 2.3 qts of oil in the sump. You need to be down to less than 1 qt for the MWL to flash.

 

A little more than 2.3 qts. You did your calc by subtracting the oil volume represented by the two dipstick pip distance, from the oil change with filter change capacity. The Repair Manual also shows a "dry fill" capacity, which is 0.4 US qt more.

"Dry fill" calc, in US quarts: 4.3-1.6=2.7

Repair Manual excerpt:



Owner's Manual:

 

Your not taking into account spirited driving. Take crisp corner with that low of oil it will slosh around and lose momentary oil pressure which will throw an intermittent blinking check engine light. This scenario is very common with G2 owners. How many posts have we seen with blinking intermittent check engine light owner posts about it on Priuschat before even opening the hood and checking the vitals.

Who knows how long it was low oil. And there's a reason it got that low to begin with.

And you cant just fill it up the check engine light goes off and you pronounce it good no damage. May not have blown the engine on the spot but there will be damage.

At the very least you will probably damage the oil scavenge ring and also the piston wrist pin bearing which happens to be the furthest moving part away from the oil sump. For instance Many a G2 owner has thrown #2 piston through the block from that bearing failing. The fact that it was so low to begin with reflects very poor monitoring of the oil to begin with probably through out its life and also probably means its an oil eater already. Very common nobody cares whats going on under the hood till it blows up. Then its how did this happen????

Damage that ring and it will eat alot of oil. Its really easy to damage that low tension ring.

Main reason people sell there prius is its an oil eater (they caused it) or it needs a hybrid battery.