OK, I pulled the intake and found a lake of oil under it. Question is, does the knock sensor penetrate an oil passage? (not likely) Or does it just have to be a head gasket. Theres no way to spin up the oil pump (crank drive) or I would and find out.

I found only only one similar problem in an exhaustive search of threads, but the "toyota experts" had no answer. ANYBODY?

 

What type of motor do you have ?

 

Sorry swampfox, its the notorious 3FVE V-6. Not even engnbldr has heard of this one. I have some nice pics. They are too big to post/iam 2 dumb 2 do it. Only clue is a bit more stain at #5 cylinder mating surface. Guess there nuttin left to do but pull the heads..uuugghh.

 

Could be from the valve cover gaskets, which are a very common problem on those motors.

 

I eliminated the valve covers and cam plugs before I pulled the motor. If it were that simple, I wouldn't be posting here. This one's a doosie!

 

Found it! Oil feed passage near inside edge of head/cylider mating point, rear of right bank. Somehow oil pressure leaked past a steel sealing ring in headgasket, filling valley in top of block with oil (1 qt+). This lake would spill over rear edge of block and onto bellhousing. The notorious 3.slow headgasket strikes again.., this time without coolant or combustion leakage.

I thought I'd post the outcome just in case some other 1 in 10,000 person has this problem. Maybe it'll save them some wasted time and mental anguish (although there is still anguish when pulling down a motor that runs just fine). I know, I know, if I wasn't so anal I'd just keep adding oil and park in the dirt.