2010 Toyota Prius burning oil

My Toyota Prius is burning oil, about 1 quart per 1,000 miles.
What can I do to stop it?

Not much, other than switching to high mileage oil and having it changed according to the severe service schedule in your Owner’s Manual. How many miles are on your Prius?

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Thanks Dave. Might try one of the carbon softening solvents to clean up the rings.

Will a higher viscosity oil cause more strain on the engine?


1 quart per 1,000 miles isn’t considered to be excessive for new cars (I think some manufacturers say 1 quart per 800 miles isn’t excessive). Keep checking your oil, topping it off when needed, and making regular oil changes.

You can try the high mileage oil that @davepsinbox_157004 recommended, but I don’t think it’s worth it. I did a change on my 09 Focus once with one of the high mileage full synthetics instead of the full synthetic I normally use and I didn’t notice a change in oil consumption.

I wouldn’t switch to a higher viscosity oil either.

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If anything, any deposits on the rings are helping keep the oil in. “High mileage” oil is supposed to have special additives to help engines with over 75k or so. I can’t say whether they work but it couldn’t hurt. They’re not heavier though. If I’m not mistaken, your Prius should require 0w20 or 5w20. Modern engines can be finicky about oil so don’t use anything heavier.

Thanks for that.

Might try one of the carbon softening solvents to clean up the rings.

Will a higher viscosity oil cause more strain on the engine?


You already asked that question… everyone on this forum can see all you your replies and all of our replies. No need to ask twice.

Do not use a higher viscosity oil. It will cause more problems.

I notice you never said how many miles are on the car.

I would suggest checking if cheap PCV valve replacement would reduce the oil consumption.


139,000 miles. Will try replacing the PCV valve as well.

Thanks for all the advice!

Considering how tightly Prius motor compartment is packed, I’m not surprised you have to disassemble down to intake manifold to have it replaced :frowning:

In my 2005 Prius, PCV failed around 95K miles and oil consumption was the issue, per prior owner records.
With PCV replaced I have around 0.5 qt loss in 5000 miles oil change interval now, mileage 128K miles.


The additives in “high mileage” oil are designed to swell the gaskets slightly, in order to reduce oil leakage. They are not designed to reduce oil consumption.


I have the exact same problem on the exact same year and model. I haven’t tried it yet but I’ve read reviews for a product called BG44k platinum fuel system cleaner and someone also said that they have the same problem on the same model and that this product fixed it! No promises but for $30 it might be worth a try. Good luck!

Also bear in mind that oil is really cheap, relatively speaking. If you have to add a quart every so often, that’s a lot better than an engine rebuild, let alone a new car.

Of course, you have to check the oil regularly. Some folks have trouble doing that, apparently.

Thanks for the clarification. That being said, we only know the OP’s car is losing a quart of oil every 1k or so, not exactly how. My original advice stands. High mileage oil certainly won’t hurt anything.

I remember reading Consumer Reports car tests back in the 1950s through the mid 1960s. One statistic that was quoted was miles per quart of oil after break-in. I remember that a 1960 Plymouth Valiant with the slant 6 engine took a quart of oil.every 400 miles. One quart per thousand miles was really pretty good.
I think you should follow the advice of others. Change the PCV valve and see if that reduces the oil consumption. I don’t think one quart per thousand miles for an older car is bad.

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