Excessive Oil Consumption on 2010 Prius

If no physical leak, the most likely culprits are valve stem seals or piston rings (or both). If compression is normal, the valve stem seals are more likely. If compression is lower than normal, the worn rings (or cylinder walls) are more likely. However, the rings can either be worn out or be “stuck “ in their grooves on the piston by accumulated carbon sludge. If stuck, sometimes trying to use solvents to dissolve the carbon sludge can reduce oil consumption, but only if the rings were really stuck rather than worn out.

Replacing the valve stem seals requires removal of the head that contains the valve assembly, which is somewhat difficult in a Prius. Replacing the piston rings requires removal and disassembling the engine block to get the old pistons and rings out and the new ones in, but that is so expensive that most Prius folks apparently choose to buy a used engine and replace the whole thing.
Hope this helps! Good luck!

 

If you have a situation where the rings have carbon and gum build up making the oil rings inaffective you can soak the cylinders with this product. All you have to do is remove the spark plugs and spray this into the cylinders and let it soak overnight. The next day, (with the spark plugs still out) crank the engine to expell any excess cleaner. Cover the spark plug holes with rags to prevent a mess. Install the plugs, run it as usual and see if oil consumption is reduced.

 

Maybe change the oil right after this treatment? Or no?

 

Good suggestion. Might be prudent to schedule this treatment to coincide with your regular oil change interval.
As always, it’s a good idea the read the label for any precautions and instructions .

 

Hi! What specialty tools do you have to make the job easier?? Are there any other specialty tools you'd recommend in general that have helped with working on cars?

 

A swivel 10mm, wobbly extention....

 

IIRC, a ratcheting 12 mm box wrench is good for the two backmost nuts, on the EGR cooler to exhaust manifold connection. A little fuzzy on why, but presumably cus it's too tight to get a regular ratchet wrench with socket in behind there.

Oh hey (lol), check first link in my signature.

 

Using and actual 1/4 rachet, like a SnapOn one, makes it easy to get to them.
A 12, 13, and 14mm open/box wrench help a lot.

 

Back in the olden days, didn't dripping automatic transmission fluid clean and unstick piston rings?

 

No clue.