my 95 camry had 100,000 km engine was puffing like crazy! There was enough sludge in it to pave my driveway! Toyota recomended an oil flush I did it 2 x engine never got better. In the end took it to a differant mechanic( private guy)the valve covers were full almost flush with crud , top end you couldn't even see any metal parts for the sluge in the motor! I know that there was a law suite for I believe 97 ish camry's and the owners won their case, a couple months before I had to put a newer engine in mine.
Gary