Canadian Tire Oil Recommendations

[rpn453]

I was picking up some Motomaster Formula1 5W-20 at the cheapest price I've ever gotten 5W-20 - $8.39 for 4.4L - and I noticed an oil recommendations card displayed on the front of the oil rack. Here's their advice:

Season: Winter
Oil Grade: 5W-30
Reason: Reduce Engine wear at startup.

Season: Summer
Oil Grade: 5W-30/20W-50
Reason: Maximize fuel economy.

Season: Year-Round
Oil Grade: 5W-50
Reason: Best low temperature performance.

At least they had a disclaimer at the bottom advising you to follow manufacturer's recommendations.

 

[55Test]

How could you maximise fuel economy by running 20w50? Maybe 20 years ago it may have worked. I've seen that card too, looks like it may have been written 5 years ago or something.