Did you read the link and others? If you didn't personally do (or oversee) the oil changes, there's really no way to know exactly what was done and what products were used. check the link.I used the Seafoam cleaner and had the oil changed and then drove home. I made it fine and the engine ran smooth the whole way, but the Low Oil Pressure light came on often at freeway speeds. I've been using standard oil (not synthetic) and usually have the oil changed at one of the local shops. Could it be a clogged filter on the oil pump inlet? Isn't there a screen?
With a history of a dented oil pan, I'd take a close look at the oil pickup, and make sure it's not crushed and/or displaced to the point of allowing air to be sucked up. Could also be the pump got a problem / damage from the event. Pop the sump and take a look - could be something as simple as a pickup tube that's not quite right.The mechanic who said I had sludge changed the oil pressure switch, so I don't think it is the switch. I didn't oversee the oil changes and have now wondered exactly what was done, but usually the Camry doesn't use any oil between changes. The car has never smoked. When the Low Oil Pressure light first came on I added a quart of oil and drove to the mechanic. He said I was 1/2 a quart overfilled (a little over 3,000 miles since my last change).
The dealer changed the oil pan last December (said it was dented), but didn't make any comments about sludge and said everything looked fine.
My mileage has dropped off significantly over the past year or two. I used to always get over 40 mpg, but now it is closer to 35. I do have 157,000 miles on the car so I thought it was the batteries or maybe the fact I do less freeway driving now. I was really hoping to get 250,000 miles out of this car.