5W-20? What's THAT about?

[Gary Allan]

quote:

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Originally posted by oddrodtodd:

Seriously though, without adding personal opinion what is the supposed advantage of thinner oils - beyond fuel savings?
Todd

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In many engines ..none. At some point in most 5w-20's existance they resemble 30 weights and even 40 (50, 60, and 70 even

) weights just due to starting temp.

But there's no defensible reason to run any heavier weight then you have to in any engine.

 

[Steelhead]

personally i run 75w140 in all my Ford crankcases since my first flathead oil burner...the new fangled synthetic 75w140's are great for cold weather starts in the T....don't have to hand crank as long
THICKER is better, keeps the oil burning down in these durn loose bearing Fords....wonder if that 5w20 would help the hand cranking in Cutbank Montana -40d F winters?

 

[beanoil]

It's all been said before.. Run 5/20, run 5/30. The MC offering from Walmart, or it's twin, the P66 5/20 at Sam's Club are both good oils that will serve you well throughout the warranty period, if you error on the side of Ford giving you a hard time in the case of a (very rare) warranty claim. OTOH, if you are comfy with the Schaffer, run it. Either should work fine out to Ford's durability testing limit, and probably beyond. The 5/20 MAY give better MPG. The 5w30 MAY give a slight advantage in preventing engine wear. But as said above, evidence presented is anecdotal, and there really is no reason to run a thicker oil than needed unless you are experimenting, or brewing.