0W-20 vs 5w-30 oil use in a 2010 Prius

has anyone heard of a supposed “Toyota technical bulletin”, now stating that it is ok to use 5W-30 in a 2010+ Prius, vs the 0W-20?

I know the owner’s manual says “no way”, and that 5W-20 can used in extremis “once”, but then must go back to the synthetic.

I welcome everyone’s thought on this.


Flailing with viscosity issues…

I don’t know, but these Prius owners seem to think it was BS from a dealership:

And here’s the confirmation from the original poster of that thread:

"I actually received an email followed up with a phone call from my dealer’s Service Advisor. He said that after our discussions on my last visit, he had gone back and re-read the Toyota letter to owner’s concerning the increase in the OCI to 10K with the 0W20 synthetic oil and said that he wanted to apologize for misinterpreting the letter !! He has assured me that 0W20 oil has been entered in the computer database for my Prius and this problem will never happen again. "

My 2007 Corolla had an original spec of 5W30 when I bought the car… A couple of years later I get a bulletin that says 5W20 regular or 0W20 synthetic is OK. Apparently Toyota had enough faith in those light oils to allow them since they were also specified in their NEW cars. Also, their dealers wanted to only stock 5W20 and 0W20 synthetic in their bulk tanks. When I ask for 5W30 in the summer they balk and do it reluctanty.

The Prius was designed to extract every fraction of economy out of the gas, and light oils made it a little more efficient.

However, the engine is basically a 1.5 liter Yaris unit. There may have been may complaints about oil usage with 20 weight, and the heavier 5W30 is perfectly good for a Prius engine, since that was the ORIGINAL spec when used in a Yaris.

So much for the EPA driven politics of fuel economy.

For future reference, the dealership will be happy to answer any question you may have about technical service bulletins for your car. They have them all on file. We’re always happy to try to help, but the dealers are the ones that actually get the bulletins.