I have a 92 4Runner V6. Today I decided to do an oil & filter change. Took off the oil pan nut, let it drain, removed the oil filter & replaced it. The oil pan nut is still off, I remove the dipstick to check it and it marks well over the high mark. Puzzled, I recheck several times, same result. I replace the oil pan nut and put in 3 quarts. Check the oil level, still the same. Start the truck, smoke and oil comes out of the muffler. The truck was smoking before the oil change, now it smokes more plus the muffler spews oil. Under what circumstance would oil come out of the muffler?

 

If for some reason your oil is slow to drain to the oil pan when your filling the engine up, oil can leak by the valve seals (if their worn) and into the cylinders and cause excessive smoking when you start it up.

How is the engine running? If your getting liquid oil out the exhaust then the engine would probably be running terribly if at all. Are you sure its oil and not condensation mixed with soot?

 

One word, SLUDGE. Pop a valve cover off to see what lurks beneath it

 

Are you sure it was the engine oil drain plug? I've seen it happen before, just asking.

 

I'm with bswarm. Are you sure you removed the engine oil drain plug?
Sounds like maybe you drained something else and then massively overfilled your crankcase.

Do you have an auto or manual?