M1 5W-30 or 10W30 for warm weather only vehicle?

Joined
Apr 27, 2009
Messages
134
Location
Missouri
Since I am not an expert in oil I was curious if there would be any benifit to running a 10W-30 oil vs. 5W-30 for a vehicle that is only driven in the spring and summer where the temperature is above 40F. The vehicle asks for a 5W-30 but 10W-30 is listed ok in the owners manual. This is for the 5.7 LS1 engine (04 GTO). Would I gain any benifit or would I actually be better sticking with a 5W-30 or 0W-30. I am currently using the 5W-30. I am more concerned with HP and/or wear protection gain/lose between grades. The oil would be M1. $22 @ WM
 
Joined
Nov 16, 2002
Messages
34,614
Location
NJ
I only suggested the 10w because it may be a bit less volatile. Otherwise, it really does not matter.
 
Joined
Oct 17, 2004
Messages
3,397
Location
Midwest, Illinois
It's my understanding that the LS1 community loves German Castrol 0w30. IIRC, the 5.7 is the same engine in the Vette. Patman really liked GC. My nephew has a goat, he runs GC. Are you subscribed over at http://www.ls2.com ? Seems like a lot of GTO owners post there... For your question, I think either is fine, but I always lean toward the smallest spread between numbers myself, so I would go for the 10-30. I see this is your first post....Welcome
 
Last edited:
Joined
Aug 21, 2008
Messages
25,050
Location
ON, Canada eh?
 Originally Posted By: Eddie
Go with the factory recomendation. Even 100 F. is considered a cold engine when normal operating temp is 190-210F
+1 \:\!
 
Joined
Jan 3, 2009
Messages
14,875
Location
Illinois
M1 10-30 will work great in summer or winter. I use it in my Merc here in Illinois and have no problems even when it's -10F. I live just across the river from you, 20 miles from the arch.
 
Last edited:
Top