What type of oil should I use on gen3

2011, phoenix, I'd use some xw-40 oil /

 

i used 5w-20

 

I run 0w 30 in winter 5w 30 in summer


Posted via the PriusChat mobile app.

 

The user manual clearly says 0W-20. I don’t see a reason to overrule it.
0W-30 is not much worse though.

 

guess you've never been in phoenix in the summer.... /

 

Do you have something different for Phoenix in the manual? Although I’m not a professional of lubes, but 0W-20 do good cooling for the engine due to low viscosity.
By the way, have you seen the coolant above 80C / 176 Farenheit?

 

The engine coolant on our 2012 Prius hatchback usually settles at 195+/-2 degrees Fahrenheit in level driving at 60-70 mph, although on long climbs up mountains it gets to 200 degrees Fahrenheit. (I believe there is an overheating cutoff somewhere at or above 205 degrees Fahrenheit.)

I understand that the oil passages on the Prius engine are designed for the thin 0w-20 oil and have been sized smaller than oil passages in older automobiles. Effective oil viscosity thins with increased heat, so to use a slightly higher viscosity oil in higher ambient temperatures is part of the owner’s manual for cars that I have owned. However, I personally would be particularly careful of using a higher-viscosity oil than 0w-20 in lower-than-standard ambient temperatures due to the possibility of insufficient oil flow to the engine bearings.

 

How would you carefully use a higher viscis oil? Not that this is a smirky question.

 

If ambient temps were uniformly 80+ degrees Fahrenheit and I observed ICE coolant temps hovering more at 199-204 degrees Fahrenheit, I would consider a 0w30 or 0w40 oil to achieve the same effective viscosity, flow through the oil passages, and oil pressure at the bearings that the ICE would have at a standard 60-degree ambient day with 0w20 weight oil. Frankly, I would simply like an analog oil pressure gauge with green, yellow and red arcs marked appropriately that I could watch during operation and change oil weights based on accurate operational observations. Not out of warranty yet, but may make that mod when our 2012 is over 100k.

 

I see no reason to change from Toyota's spec.