Excessive oil consumption

I have a 2004 toyota corolla 80k miles. car is using about 5-6 quarts of oil amonth. no external leakage on car at all. smokes on start up occasionally but not while driving. I think oil is burning via catalytic converter.gas mileage down significantly. acceleration not as good also. rough idle. any ideas on what type of repair i may be expexting and would it be worth it.

5 to 6 quarts of oil per month? That is a very serious hemmorage.

You need to get a compression and leakdown test. The only way you could be drawing that much oil into the cylinders is if you have a breech in your headgasket between the cylinders and your oil passages and the intakes atrokes are actually pulling the oil in.

Catalytic converters do not cause oil burning. They’re well past and input nothing into the combustion chambers. As a matter of fact they can mask a certain amount of oil burning by “catching” the smoke…but not in the quantities you’re describing.

Has this car been overheated? Repeatedly?

Expect a new headgasket as a minimum and, if coolant has been mixing with the oil, maybe even a replacement engine. Cost will be high…perhaps a grand for a headgasket and more if the head needs to be milled. Even more if there’s further engine damage.

Will it be worth it? Normally I’d say yes, but if the condition of the engine is representative of the condition of the car…

PostScript: I hope I’m wrong.

You probably need a Ring job, and if you do have it done use only synthetic oil there after.

Wow, that really is excessive oil consumption! How long has it been burning this much oil?

You’re likely looking at a very expensive repair, and without knowing the condition of the car itself it’s hard to say whether or not repairing the engine would be worth it.

Car hasn’t overheated, never. coolant levels haven’t dropped. car in good condition and maintained well.

probably six to seven months. car in good condition inside and out. no leaks anywhere. otherwise fine.

Remove the oil dip stick and smell the oil. Does it have a gas odor? If so, the fuel pressure regulator may be leaking. When this happens, gas ends up mixed in with the oil causing the oil to become volotile to where a vaporizes and is burned in the engine via PCV system. This would also the explain why the gas mileage is down.

Tester