Prius V Oil Leak

Good afternoon all,

The car in question is a 2012 Prius V Five model.

We took the car to the dealer to get the oil changed. After about 5,000 miles there was some knocking when the car was initially started. Checked the level and the oil was low. Added oil thinking maybe the dealer had shorted us for some reason. Went on with our day.

5,000 miles more, at the next service point (the next 10,000 miles mark) had the oil changed again, same thing happened again. Added oil and it was fine.

Now, here I am at the third 10,000 mile point. I go to change the oil myself this time and there is no oil on the dipstick at all.

The top of the timing cover/area has very old, black, dusty oil. Not at all fresh. Not at all shiny and very thick. There is a trace of a leak up there, but I don't think that this is my problem. At least not at the top of the block where I'm seeing this very old, small oily area.

Inspected the engine block and found behind the block, on the back right side, where the oil pressure switch/sensor is located is a light coating of fresh oil. Shiny and wet. However, this fresh coat is isolated to the back, right side of the engine block, right where the oil pressure switch, and two other wire/connectors and their wire harnesses are located. There is no oil anywhere else. None. No spray or collections of oil/dust deposits anywhere else behind the right wheel, or aft going back behind the block. All clean. There is no evidence of oil on the back of the car, the bumper, above the exhaust pipe, etc. either. What you see in the pictures is the extent of any oil leak I can see.

So, I took a wrench to the oil pressure switch and was able to rotate it. It was about two to three threads OUT of its hole. The body of the sensor had two very clean, wet drips on it. I don't see that anywhere else.

Two questions. One, should the pressure switch be flush with the engine block, or should it be slightly OUT, showing those two or three threads like I originally found it? Two, how do I loose that much oil with this being my only evidence? I would fully expect to see an oily, coated, dusty mess everywhere on that side of the engine compartment and the right wheel structure.

Thanks to all of you for your help and advice. I hope these pictures help.

 

Wow rjparker! Thanks so much for the info. The rate of consumption you mention does just about fit what I'm seeing. We are going to set a reminder (marker on the windshield) to check the levels every 1,000 miles to see what happens. I also used a degreaser and sprayed down the area on the back right of the engine block to see what starts to appear and where, in case I have another issue going on. I do appreciate your help. Thanks!!

Is there anyway to fix this? An "additive" to clean the pistons, rings, or something like that maybe?

 

Yup, 147,000. Gonna have to keep an eye on it, and be much more frequent with our oil level checks.