Originally Posted By: khittner
I've used both the Amsoil engine flush and Kreen (as a piston soak) in my '02 Toyota Camry's 2AZ-FE engine. The engine has 264K miles on it, and it began using a quart of oil every 900-1200 miles, depending on viscosity starting at about 230K. I originally thought that I simply have the sticking rings/too-small return holes problem that is fairly common to these engines, and perhaps I do, but neither of these products, used as directed, resulted in any obvious "de-gunking" of the engine (rings, lands, or anywhere else) and has made no noticeable impact on the oil consumption. I've had a leak-down compression test done on the engine by my usual independent mechanics' shop, and the engine has compression in all cylinders within 5% of a new spec, so I'm thinking now that the oil is coming in through the valve guides, rather than past stuck or worn piston rings.
I'm quite familiar with that year 2AZ-FE. My 02 Camry lasted to 354k burning oil. IMO its a little of both. Clogged piston oil return holes, leaking valve seals. Nothing will unclog those holes short of a teardown and a drill. So if its just clogged piston oil return holes, a thicker oil will help. If its valve seals, you will definitely benefit from a HM oil with conditioners/swellers. You will see blue smoke at startup after sitting overnight, or for a couple days. Have someone start your car so you can watch the tailpipe. Very important on these engines, change the coolant. often. Its directly related to oil related issues (hot spots frying oil) , and potentially fatal flaw where the head bolts could randomly separate from the aluminum block. Best luck with oil I had was M1 10w30. Great cleaner, did a fantastic job with the valve seals.