Mystery oil loss

I have a 2009 Toyota Matrix that has 127,000 miles on it. It has had several sources of oil loss in the past year and now it just seems to be burning it. I am very skeptical that a toyota engine is burning oil at 127,000miles. I replaced a part called a pcv valve as well as a seal that was causing leakage. Now I am losing about a quart every 1000 miles and no leaks can be found. Can anyone think of other things that would cause oil loss besides burning?

While a quart every 1000 miles is on the high end of the “acceptable” curve, it is considered acceptable… even on a new engine.

I guess what I’d do is check under the valvecover to see if there’s evidence of oil coking (black gump). If there isn’t, I’d consider the usage normal. If there is, I’d probably try and additive from the parts store to see if I could clean it out, and once done I’d switch to synthetic.

It is not at all unusual for an engine–from any manufacturer–to consume 1 qt of oil every 1,000 miles–especially if that engine has been in service for 127k miles. In fact, virtually every car mfr states in writing that consumption of 1 qt per 1k miles is within normal limits. The only exception that I am aware of is Audi, which claims that it is “normal” for some of their cars to consume 1 qt of oil every 600 miles, even when brand new.

If this is a higher rate of consumption than the engine used to have, I can understand your concern, but this is not something that really should concern you. Just make sure that you check the oil at least once every 2 weeks, and replenish it as soon as the level falls by 1/2 qt. Also, make sure that you are changing the oil on the recommended schedule, in terms of both odometer mileage AND elapsed time. Typically for a Toyota, this means every 5k miles or 6 months, whichever comes first.

The oil ring groves in the pistons of Toyota 2AZ-FE engines become blocked with carbon.

Service bulletin T-SB-0094-11 contains information to address this problem.

Some 2006 – 2011 model year vehicles equipped with the 2AZ-FE engine may exhibit engine
oil consumption. The piston assembly has been changed to minimize oil consumption. Use the
following repair procedure to address this condition.

If it was my car I would try a top engine cleaning treatment before replacing pistons.

A top engine treatment system won’t remove carbon from coked up oil control rings. A top end engine cleaning does just that. Cleans the injectors, intake valves, and the combustion chambers.

If you want to try and free up stuck oil control rings you need to add something to the oil.

And that something is this.


Lexus had us pour 1 ounce of top engine cleaner into each cylinder to soak for 4 hours on 4GR-FSE engines before the revised pistons came out.

I don’t see how that would work?

On a four cylinder engine, the engine is tilted back so the oil in the head drains back to the drain holes. On a V6 engine the pistons sit at an angle.

If you add one ounce of the cleaner to each cylinder, the cleaner is going to pool at one area of the pistons. If the cleaner slowly leaks past the compression rings in one area it’s not going to get at the full circumference of the oil control rings.


Crank the engine over for 30 seconds each hour to coat the cylinders and pistons. Engine must be hot before adding cleaning solvent, the fumes will make your eyes water.

Thanks for all the good ideas!

There was a time, back in the day, when at 127,000 miles, the engine was usually ready for a valve and ring job…If it only burned a quart of 30 weight every 1000 miles, the owner would be proud of that and brag about it…

And while you are doing the valves and rings, you might as well do the bearings too…