Lexmex

Keep in mind there is nothing wrong with continuing to use 5W30, but with Toyota's backing on this (not coming out of my mouth like I have said with 0W40 but the actual manufacturer.), the 5W20 will work. For those of you at sea level, you should not have an issue with going ahead and giving 5W20 a try.

HarrierAWD

I've used 5W30 dino from the beginning. 73K miles later, not a drop is burned. Not sure about the chewing thing.

5W20 may save some fuel, but it might pass through the piston rings easily. So those who switch might notice some oil burning. Especially those who have high-mileage engines.

TunedRX300

Multiple used oil analysis on 1mzfe based Toyota/Lexus models from 98-03 showed 5w-30 dino oil is sheared to a 5w-20 oil. The consumption of acid neutralization additives is significant higher with 1mzfe as well. Multiple UOAs across all 1mzfe models shows a trend that the "narrow coolant passage", as termed by Toyota, put a lot more stress on the both synthetic and dino oil.
One UOA in the thread linked above showed the owner took a sample of Toyota virgin dino oil at the dealership. He took two more samples after 200 miles and 1500 miles for comparasion. The lab showed the oil is sheared to a 20 weight already after 200 miles, after 1500 miles acid neutralization is lower to 50% of what's measured in the virgin sample. This type of "oil chewing" is not typical for a Toyota engine.

dzell81

So I finally got around to changing the oil this week and found out some bad info. It looks as though my main rear seal is leaking. I noticed a couple of drops of oil on the garage floor the other day but didn't think much of it. After I got under there and looked around it little, it was fairly apparent that the oil was coming from my RX and out of that juncture.

Has anyone had any experience with this? I don't think I’m capable of changing it myself as it will probably require removing the engine and/or trani. I'm thinking about letting it go for a while though.

Also, would this be covered under the warrantee?

PS: I might repost this under a different heading to get some more feed back. And thank you all for the detailed discussion on changes and oils - that part went well.

Lexmex

It is a nasty problem when you have the rear main seal go. A few people on CL have had this issue, so I know they will have comments.

Not that is even guaranteed to fix it, but you may want to look Auto-RX, which I have talked about before. It is an additive that goes into the oil and COULD help the leak for now. However, eventually, that rear main seal can and will go.