What can cause an earlier change in oil color in Corolla 1993 (4AFE engine. Fuel injection, made in Japan).?

Question

I have Toyota corolla 1993 with 4AFE engine. Apparently there is no problem with the engine, but I see that color of the engine oil is turning dark very soon. I can also see black powder in the engine exhaust. I don’t feel any oilishness in this powder. The engine oil level however slightly reduces in a month time. My engine looks good as it is still throwing water from the exhaust however I feel that compare to before engine sound and idle speed is increased a little bit. What could be reason for change in oil color? Can worn-out engine valve seals cause change in oil color? Any ideas?

Answer 1

The symptoms you present indicate that the engine is running rich. Take it to a trusted mechanic and they can fix it.

Answer 2

The black powder is the key. I'm betting that you're running rich -- in other words, the gas/air mixture has too much gas in it. The black stuff is making your oil dirty.

Your car has fuel injection, and it is impossible to tell exactly what is wrong with your system from your description if indeed it is running rich! It might be some defective sensor, or a bad wiring connection, etc. I'd check the O2 sensor in the exhaust manifold first, but only a trained mechanic w/ a diagnostic center can tell you for sure.

Hand on to your a**... repairing those old Japanese cars can be horribly expensive.

Answer 3

i own a repair shop,and as the engine gets a little older it will get the oil a little dirtier a lot faster,,and if its starting to use a little ,it may very well be the valve stem seals or the rings maybe getting some wear on them also,,these are good engines ,,but they do wear out like any other ones do,,you might want to change the weight of oil your using in it,,sometimes this will help one cut down on using oil,,i have changed a few to a heavier oil ,and it has helped them,,all you can do is try a few things to improve it,,its probably getting a few miles on it,,but it will keep going,,they always do,,good luck with it,i hope this help,s.,,have a good x-mas

Answer 4

Dodge man had a good answer concerning blow by due to age. But I would like to add that you might want to switch to an oil specifically designed for older high mileage cars. A good brand to switch to is Max Life. and there are several other oil companies that make oil for high mileage older cars as well.

Answer 5

Blow by the rings letting raw fuel and burnt gasses pass to the crankcase and into the oil. you are running rich and the water is ok if not to much the catalytic convertor turns some of the carbon monoxide to water as it passes thru.

Answer 6

water leaking into the oil maybe the gaskets are teared in the heads try doing a oil change and see what hapens