I have seen the "Unofficial" oil Toyota Chart that says 0w20 / 5w20 can be used in my Corolla (down to 1999). I have read the TSB (a while back) that showed the back spec to 5w20 down to 2006 IIRC. So... What is the reason Toyota did not back spec the 1999-2005 VVT-i 1ZZFE to 5w20? I know these year toyotas has small oil passages that would clog and result in oil burning. Seems to me that a thinner oil would flow better and reduce the clogging problem. As far as a timing chain, lots of new cars run chains and use 0w20.
Yes, the manual says 5w30 but my curiosity is getting the best of me. I want to maximize my fuel economy plain and simple. This new to me Corolla has some varnish that I am working to clean up. If all goes well, I plan to run 0w20 for 10k or so then send off an oil sample.
Am I crazy to even be thinking this. I guess my biggest question is why not?
Yes, the manual says 5w30 but my curiosity is getting the best of me. I want to maximize my fuel economy plain and simple. This new to me Corolla has some varnish that I am working to clean up. If all goes well, I plan to run 0w20 for 10k or so then send off an oil sample.
Am I crazy to even be thinking this. I guess my biggest question is why not?