Cross Country Trip : 5W20 or 5W30 Synthetic ?

[ChrisD46]

What are you seeking with the choice between the 20 vs the 30?

Interstate engine protection at higher , constant temps is probably the better question I am seeking - Southeast USA to Pacific Northwest USA in the Spring (i.e. no snow in route) .

 

[JavierH19]

Are you serious?

I agree with you on that. But it's not a terrible idea to temporarily switch to a 0w20 when 5w-30 is spec in extreme colds where you don't have access to a block heater and don't do long drives since the oil will never thin out. But by extreme colds i mean like 25 below zero or worse. If it's just 15 below I wouldn't think twice about running a 30 grade year round.

 

[tyman]

Whatever the oil cap and owned manual says.

 

[Malo83]

5w30

 

[cheesepuffs2]

Interstate engine protection at higher , constant temps is probably the better question I am seeking - Southeast USA to Pacific Northwest USA in the Spring (i.e. no snow in route) .

It won't be higher temps. Your cooling system, assuming it's in good working order, will regulate the operating temp of the engine with ease as you cruise along at near constant speed. Don't sweat it.

 

[Bill7]

For extended high speed highway driving, a higher HTHS would benefit you.
Please do a google search for: HTHS wear graph

 

[ZeeOSix]

Interstate engine protection at higher , constant temps is probably the better question I am seeking - Southeast USA to Pacific Northwest USA in the Spring (i.e. no snow in route) .

xW-30 has higher HTHS viscosity, which will give better protection ... stay with xW-30 unless you think you need/want to save a few bucks in fuel.

 

[Bill7]

xW-30 has higher HTHS viscosity, which will give better protection ... stay with xW-30 unless you think you need/want to save a few bucks in fuel.

I prefer to only use 5W-30 in all my vehicles, as the higher HTHS will protect better during high heat/high RPM driving like going up extended inclines with 8 people + heavy luggage in the vehicle and air conditioning on. To the OP, if you haven't already, please google HTHS wear graph.