Had my grandson bring the 1999 4runner over and he stated it needed oil. I asked him if he brought any and you know the answer to that. Searched the garage and found a quart of conventional oil. Looked at the dip stick and no trace of oil. Pored in the quart, and still no joy on the dip stick. Found a 5 gallon jug left over from my last Bimmer change, and put another 2.5 quarts and still no trace of oil on the dip stick. At this point I made sure I had the engine dip stick in my hand and that I had actually removed the engine cap where I was pouring oil. Called my granddaughter who had done an oil change last September on this truck while I was on vacation and asked how much oil she put back in. Answer- a quart and a half! I put over another quart in and filled it back up to the fill line. I asked my grandson if he was having problem with this truck and he said it just took a little longer on start up. I think it's a testament to the Toyota designers that this truck has been running on only a quart and a half of oil for the last 4 months and didn't grenade.