Helped my neighbor change the oil on his XC90 (8500 miles since last change) and the vacum extractor only took out 2.1 quarts. The filter yielded maybe 1/4 of a quart. We pulled the oil pan drain plug and got maybe another 1/4 quart out. The car was not up on ramps so it was level. The dip stick showed no oil. We had to put in about 5.5 quarts to get it to 3/4 of the way above the min level on the dip stick.

So it would seem he was driving with about 3 quarts in a system that takes 6.1 quarts, but it appears the low oil light never came on. The car does not blow smoke and the motor sounds fine. There were no signs of oil leaks. It has 108,000 miles on it and is serviced by an excellant Volvo dealer service department. Last service was the oil/trap PVC system.

Any ideas why the oil light did not come on?

 

Because it is only an oil pressure light. It does not have a low oil level light.