No 'fill line' on oil dipstick?

Those are the fill limits. Anywhere between is good. Bottom add oil , top too much oil and this may be unwise. Drain and new filter = 3.9 qts to top. Drain and old filter = 3.5 qts. I prefer them to add only 3.5 with filter. This puts level smack in the middle.

 

But, that implies that you are operating about 10% below the designed oil capacity. Sure, it will run fine, and everything is bound to stay slick. What will change is that 3.9 will endure longer than 3.5 under identical conditions.

The key is to top off carefully. Use a completely flat surface. Give sufficient time for the oil to return to the pan (3 minutes with a hot engine; 5 minutes or more with a warm engine). Each car takes some getting used to in this regard. So, practice a little trial and error as you progress up the stick.

Death to mechanics that return cars 0.5 to 1.0 over their max capacity! :guns:

 

What do I do about my new Prius having too much oil? I checked the level with the car warmed up, turned off, and on a level surface, after waiting a few minutes for all the oil to drain back. It's a bit over the "full" bump. Do I have to take it back to the dealer and get the rolling eyeball treatment from them, or is there something I can do myself (preferably not by crawling under the car and opening up anything)?

Can I just pretend I didn't check this? What horrible things will happen from too much oil?

Barbara

 

Typically a minor amount over (say, 1/4 inch) does not imply doom. Remember, the manufacturer's engineers are always gonna put in a safety margin, and worst case, even a quart over is not gonna produce dramatic, serious harm.

First, be absolutely sure that all four wheels are on the same level surface (use a level on the car's door jam if you have to). The inside of the oil pan is an irregular volume, so certain tilt angles will be more amplified on the dipstick. If you are in your garage, be aware that most garage floors are pitched towards the entrance about 1.5 inches or so from axle to axle (look at the foundation wall concrete block, if you have that. One quick check of the garage floor, or anywhere else's effect, would be to reverse the car's orientation and see if the dipstick then reads a similar distance south of the mark.

BTA, I don't have my Prius, and therefore am unfamiliar with this model. Perhaps those more acquainted with their Prius' slippery juice can provide a clearer answer.