I have a 2007 LS460 with 42K miles. After the dealear changed my oil at 5K and 10K, I decided to do my own because of their sloppy work - they would leave oil smeared on the engine cover around the filler cap. Like you, at the 15K interval, I found that removing the filter housing took a hell of a lot of torque - Nothing like a professional doing the job and charging you $149. Ever since, I have been changing the oil every 5k and have not had any leaks. You have to make sure that o-ring stays in the housing grove when you tighten the housing. It is the o-ring that creates the seal and keeps the oil from leaking. I use a toyota filter ($10.42 at the Lexus dealer) and Mobil 1 0W-20 oil.
Tourqing the oil canister to 100 ft-lbs is living dangerously - I torque my at around 30.
Thanks for confirming that the filter will not leak if the housing is torqued to 30 ft-lbs.After i discovered the original leak,I removed the filter and housing at least three times in an attempt to ascertain what the problem was.I even changed the o ring all to no avail.Each tme i removed the housing , repositioned the o ring ,and then started the car,i could see the o ring being blown out by the oil pressure,generally at the same point on the ring.After the third time,i began to believe that the service manual was wrong and more torque was needed so I tightened it to about the same torque that the dealer did.In hindsight, maybe Whitster was correct----cross threaded housing.
Does your housing screw in freely without much torque required before tightening? Usually when you have cross threading there is a lot of resistance during the first few turns. What I have noticed is that you have to be very carefull with the first few turns to make sure you are not cross threading. My experience is that after about 3 or 4 rotations by hand, it gets pretty snug, and I have to use a wrench to complete the installtion before the final torque.
I agree with the others, this is a poor setup, toyota could have easily used a regular screw on filter like they do with many of their other models - our 2005 camry has a regular screw on fillter under the engine that is so easy to change. The Lexus oil change takes more time than it should. Plus that housing does not look like it is verey durable and over time may be subject to cracking and thread stripping(especially when the Lexus dealers tend to over tighten them)