2008 Prius Burning Oil Fast

A new engine with less than 280k miles......or pay more attention to the oil level in your car.

 

move to the next viscosity (i like 15W40 oils) AND add oil to the full line with every fueling.

 

sawdust?

 

no, that only works for rear diff.

 

Mine was eating about a liter every 1000 miles at 180k miles. So at 280k, i'd say your engine needs a rebuild or just pop in a low mile one like i did.

 

As others have mentioned, the only fully long-term solution is to replace the engine, or to rebuild it with new gaskets. I agree with friendly - moving up to a higher weight oil like 15W-40 will help reduce oil use/leakage, but this is only patching/masking the problem. I would also avoid synthetic oil as synthetic generally will leak more quickly in leaky engines for a variety of reasons.

There are also engine oil stop leak solutions you can add to the oil which can help reduce use by causing the seals in the engine to swell slightly. Note you shouldn't use too much of such solutions as they affect the oil in other ways which aren't always positive. I would probably put in high weight oil and half of a bottle of stop leak and then check the oil on every fill up and see if it makes a difference. Some oil guys say to only use this when the engine is in its last years, but this sounds appropriate.

The amount of oil used may stay the same, but likely it will get worse and worse until eventually something happens in the engine to take it fully out of commission. Most likely the days left on your engine are numbered, but considering the 280K+ miles run, I'd call that an enormous success.

 

Are you saying you never change your oil, but but rather just top it up every 2K miles and when you change the filter?

 

LOL, the oil "changes" itself at the rate of every 2000 miles.

 

You're really only burning about 1q/1,000 miles.

Yeah....you're going to need to undergo a motor transplant soon, but remember that even if there's no observable oil on the dipstick, there's still some left in the sump.
At your current burn rate, you're going to fod out other things (cat, plugs, etc....) but fortunately you have some time yet (like 20-50K, probably)
Meanwhile club up to a 10w30 and start looking for a donor motor, and line up a trusted wrench to do the transplant.

I'd also replace the catalytic converter while I had the patient on the table.

 

apparently it's cleanable: Acid bath and P0420 | PriusChat

 

Hmmm....never thought about that.
Learn something new.....

If you don't live on relatively free soil however, you can get a used cat for less than $200 installed....which seems to be more environmentally responsible, especially since most people in the US live in places where a VET is some place that you take a sick pet.

If the Acid bath is cheaper than 200 bucks and if it works....well, that's even better.
I'll look into it.

 

There are some things that can go bad that will consume oil quickly without needing a new engine.

Have you replaced the PCV valve yet? It's fairly easy to do in about an hour.

I'd also do a compression check. You'll need a techstream (get a cheapy one on amazon for $35) in order to do this. If the compression is within spec and they are somewhat even on all 4 cylinders, then you may have stuck oil rings. There are a dozen or so different methods for freeing stuck oil rings without removing the engine. The best methods usually involve letting the cylinders sit for a week or so with the plugs out and enough Marvel Mystery Oil soak through the carbon buildup that has frozen the rings. Other quicker methods involve putting in an oil additive and running the engine at 2K RPMS for a while and then immediately changing the oil.

If your compression is bad, then forget it and just buy a good used motor.

 

i'm a great believer of piston soaks for a minor oil consumption, but in the OP case is way too late. by the time engine consumes 1 qt of oil in under 1000 miles, oil rings are all worn out or broken.

and BTW, MMO is not strong enough.

 

Sure. That was just an example of a popular method. If you want to suggest a more aggressive method? There are chemicals specially for breaking up ring land deposits.

 

Ring groove deposits actually, not ring lands.

 

Yes ring lands. Grooves are between the ring lands and the carbon builds up between the ring and the ring land.

 

You apparently don't know what a ring land is. The land is parallel to the cylinder bore wall, the rings and
ring grooves are perpendicular to the cylinder bore wall.

Hence the carbon cannot build up between the ring lands and the rings - they are perpendicular to each other.

Carbon builds up on the lands and often at the ring groove roots.

 

I know exactly what a ring land is:



The grooves are the spaces between the lands that the rings fit in.

Oh and if we go by your definition, then the groove is ONLY the bottom of the groove and not the walls of the groove. The grooves and lands share a surface.

 

OK, then you don't know what you are talking about. deposits are in the grooves making the rings stuck and wearing against the bore.