Motor oil vescocity question

[dan]

2008 Pontiac Grand Prix, Naturally aspirated 3800 Series III L-26 engine sort of a burning question that’s been in my mind for some time…

the earlier Series II L-36 and supercharged L-67 engines recommended 10w-30 Motor oil, the newer Series III L-26 and supercharged L-32 engine recommend 5W-30 Motor oil, my question is would it be safe too use 10W-30 Motor oil in the newer engines? and what differences are there in the internal construction between the two engines that it would recommend the thinner oil when cold, the only internal differences that i am aware of between the two engines is the Series III has different connecting rods.

maybe they just figured 5W-30 would be better over 10W-30 for cold starts after all?

Topic

[college man]

The 5-30 is used to get the oil circulating faster on start up.
Stick with whats recommended.

[Bill]

It depends on the climate you live in. If it drops to below zero at night 5w30 would be my suggestion.

[zero]

Always use what the manufacturer recommends.

That being said most GM cars that spec 5w-30 or 10w30 usually state something to the effect of: Below 0c (freezing) use 5w-30 above 0c you can use 10w30.

Basically the 2 are interchangeable until you get into variable valve timing and whatnot.

[Author]

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