Question2002 Toyota Corolla - automatic - 236,000 miles - driven 600 miles a week, mostly at highway speed (65 mph) for last 4 years. Average fuel economy 37 miles/US gallon. Runs well.
For the past year the engine has been losing just under 1 quart of oil every 600 miles, no oil leaks on engine or ground. No visible blue smoke from tail pipe. Heated oil smell from engine after driving. Tune up and valve head cover gasket replaced two weeks ago along with up-stream 02 sensor (check engine code), solenoid re-set as well, now Check Engine Light indicates catalytic converter problem. Emissions check (Ontario, Canada) is due within next 2 months.
Does it need new valve seals? If catalytic converter is replaced first, how long before oil damages it again? I would like to keep the car for another 2 years (31,000 miles) when it will be at 500,000 km mark (310,000 miles) at the next emission check
AnswerIt could very well be the valve seals, a sign that the seals are bad is usually some blue smoke from the exhaust for a couple of minutes when cold starting, you may not notice this from the inside of the car so the next time when starting in the morning walk back and look for this.
Catalityc converter failures are not uncommon on these models, any oil getting to it is not good for it, it's hard to say how long it would take to damage the new converter, if oil consumption is the case, but then 1qt in 600 miles is excessive. It's possible that it was due to the leaking valve cover so I would do another oil consumption test first, if you can get it to about 1000 miles per quart that would be acceptable.
