Sorry... can't figure out how to post the PDF or the TSB ....

A Toyota Tech Service Bulletin # EG018-06 issued on March 29, 2006, indicates that ILSAC GF-4 , 5W20 or 0W20 may be used in a variety of modern Toyota engines that used a heavier oil. The list includes the "MZ" series engine (3MZ-FE) 3.3L V6 in my Sienna.

Originally, it called for a 5W-30. I've been using 0W-30 for years and I'm wondering if I can safely 'down grade' to a 5W20?

Any thoughts??

If Toyota and the rest of the manufacterers would put the money they spend in useless TSBs into increased quality everyone would be happier. That being said, it's obvious the switch to 20wt oils is driven by economy numbers. Their high quality is just an added bonus. I've run 20wt oil in a 81 Toyota with 650,000 miles on it. I'm glad they sent a bullitin saying it won't hurt anything.

It should be just fine. Many people use oils weights 2 or 3 above or below the recommended weight for their vehicle and it still performs well. I personally always stick to the recommended weight in the owner's manual. However, 5w20 or 5w30... not much difference. I use 5w20 for my truck and 5w30 for my wifes car. Sometimes I will top off upto a half a quart here and there with the other vehicle's oil if it's all I have left.

If you do, monitor closely for any increase in oil consumption. If it occurs go back to what you were using previously.

Good advise. I actually found consumption to decrease slightly changing from 5W30 to 5W20 in a 93 3.0L Ford Aerostar. YMMV

Up here in Alberta, 5W-20's generally cost quite a bit more than the 5W-30's motor oils. So for me, I'd be sticking with 5W-30.

I have a 2006 4 cyl 4x4 Toy p/u and I have bounced between 5w/20 and 5w/30 oils with a run of Castrol green 0w/30 and I haven't really noticed a whole lot of difference. Seems I lost a couple of tenths of a MPG using the scan guage running average going from pp 5w/30 to 5w/20 valvoline syn oil and the pp was run less than year and a bit over 5,000 miles. I miss the 99 cent with a rebate sales.

My experience IN GENERAL is opposite to the common wisdom that thinner oils produce higher consumption. I've always noted higher consumption with *thicker* oils when the dominant source of consumption is past the rings. If the valve guides are the dominant path for consumption, then yes thin oils do get consumed faster. My working theory is that oil control rings are more able to scrape thin oils back into the sump, resulting in less being left on the cylinder walls and burned in the cylinders.

Here's a link to a Camry forum that shows the TSB...

http://camryforums.com/forum/showthread.php?t=725

Come now, surely you jest! That's not possible. Heresy! JK

LOL! Try and see.

^You're preaching to the choir. But my goodness, backspecing a 93 Aerostar makes you a real heretic rebel around here.

Heretic rebel, hmmmm is that redundant?

I can't see why the TSB only applies to '06 and '07 vehicles. There are many '05 vehicles out there with those same engines (my '05 Tacoma has the 2TR-FE).

'cause they all already sludged up and died....Toyoda dealer [censored] me off the other day.

Most if not all 5w30's shear into a 20wt sometime throughout its usage.

The 0w30 is an excellent weight. I would stick with it.

I don't look for the cheapest oil. I do use the cheapest synthetic oil. Since 0w30's are usually full synthetic, if you move to a 5w20, stick with a synth. Can get pretty toasty in Tx

Maybe they changed certain things in those engine years... Unlikely, but possible.