5w30 vs 10w30
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Instructor
Joined: Sep 2004
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5w30 vs 10w30
Right before I got my c4 I moved to SC so shouldwhat weight oil I use change from when I lived in VA? I had a 92 c4 before my 94 in 1995 I sold the 92 in 1997 but when I had it I used 5w30 but when I went to the track the other night a guy there said 5w30 might be ok but would wear the top end of my cylinders out faster than 10w30 would.
I thought at warm/running temps 5w30 and 10w30 both act like 30 weight oil and it wouldn't matter and when it's cold the 5 acts like 5 weight and the 10 acts like 10 weight so in the summer and all why would it matter which you ran?
I thought at warm/running temps 5w30 and 10w30 both act like 30 weight oil and it wouldn't matter and when it's cold the 5 acts like 5 weight and the 10 acts like 10 weight so in the summer and all why would it matter which you ran?
Melting Slicks
Joined: May 2003
Posts: 3,490
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From: Hewitt NJ
Originally Posted by nato
Right before I got my c4 I moved to SC so shouldwhat weight oil I use change from when I lived in VA? I had a 92 c4 before my 94 in 1995 I sold the 92 in 1997 but when I had it I used 5w30 but when I went to the track the other night a guy there said 5w30 might be ok but would wear the top end of my cylinders out faster than 10w30 would.
I thought at warm/running temps 5w30 and 10w30 both act like 30 weight oil and it wouldn't matter and when it's cold the 5 acts like 5 weight and the 10 acts like 10 weight so in the summer and all why would it matter which you ran?
I thought at warm/running temps 5w30 and 10w30 both act like 30 weight oil and it wouldn't matter and when it's cold the 5 acts like 5 weight and the 10 acts like 10 weight so in the summer and all why would it matter which you ran?
You're correct when hot both will have the same viscocity so I'm not really sure what that guy meant by his comment. When cold the 5 will flow a little bit easier. I can see you getting away with 10W30 if you lived in a super hot climate, but it's not really necessary.
Melting Slicks
Joined: Apr 2004
Posts: 3,287
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From: n/a SC
Mine has always used 5w30 M1 and I haven't had any issues seems to me like you are saying when hot both are 30 weight so if anything 5w30 is better because the only difference will be the 5w30 will flow better in colder weather.
Burning Brakes
Joined: Jun 2003
Posts: 827
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From: Henderson NV
Since most engine wear occurs at start-up, the thinner the oil, the better. The beautiful part of the L98, LT1, etc. is their longevity, and the proper grade of oil plays a very large part in that. Whatever brand of oil one uses, if it is the proper viscosity and changed regularly, these engines will live long and prosper. I had an 87 with 155,00 miles on the clock; never torn down, never suffered component failure and it used less than 1/2 quart between 3,000 mile oil changes. Most of that, I suspect, was from worn valve seals. One more thing, these engines turn over at half the revolutions at speed as engines did with the old 4-speed trannys. This contributes greatly to their long life but there ain't no substutute for regular oil changes of the proper viscosity. It is the contaminants in old oil that can do damage, which is why I never exceed 3,000 miles on an oil change. Then I run what brung me; Mobil 5-30W. 
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
I would probably stick with the 5w30 during the winter, if youre going to be driving alot.
It can be quite cold in the mornings and at night, but the averages for the next couple months are going to be about 50.
It can be quite cold in the mornings and at night, but the averages for the next couple months are going to be about 50.
Le Mans Master
Joined: Dec 2002
Posts: 6,715
Likes: 2
From: Santa Teresa New Mexico
Originally Posted by nato
Right before I got my c4 I moved to SC so shouldwhat weight oil I use change from when I lived in VA? I had a 92 c4 before my 94 in 1995 I sold the 92 in 1997 but when I had it I used 5w30 but when I went to the track the other night a guy there said 5w30 might be ok but would wear the top end of my cylinders out faster than 10w30 would.
I thought at warm/running temps 5w30 and 10w30 both act like 30 weight oil and it wouldn't matter and when it's cold the 5 acts like 5 weight and the 10 acts like 10 weight so in the summer and all why would it matter which you ran?
I thought at warm/running temps 5w30 and 10w30 both act like 30 weight oil and it wouldn't matter and when it's cold the 5 acts like 5 weight and the 10 acts like 10 weight so in the summer and all why would it matter which you ran?
It won't make any difference.
Melting Slicks
Joined: Oct 2000
Posts: 2,491
Likes: 1
From: prescott AZ
Originally Posted by Bruthish
INMO...run whatthe manufacturer recommends. 
What makes an oil cover a larger viscosity range (5-30 vs 10-30) is the viscosity modifiers that go into the oil. They replace actual oil with a product ( the modifiers) that do not provide the protection of oil. So really there is less OIL in a 5-30 than a 10-30 and less protection.
There is a lot to consider besides this. If I lived in a very cold climate and did a lot of start ups and little highway driving I might use a 5-30. But it would have to be when the temperatures were 0 degrees and below. Otherwise, I would continue to use the 10-30 I have been using for the least 12 years with no problems. I would never use a 10-40 for the same reason.
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Le Mans Master
Joined: Feb 2002
Posts: 5,970
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From: San Marcos Texas
So what about Mobil 1 15w-50? It gets hot down here(we only see 32* one day a year), plus I drive like a mad man...
I've been using Mobil 1 15w-50 for over 10 years in all my turbo and sports cars. Only the wifes car gets 5w-30
I've been using Mobil 1 15w-50 for over 10 years in all my turbo and sports cars. Only the wifes car gets 5w-30
Race Director
Joined: May 2001
Posts: 14,165
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I run 10w30 in mine. Why? Well I like the green bottle cap on mobil 1 better than the red cap. 
Seriously though the multi-grade oils require friction modifiers and such to give them their properties. The bigger split between the viscosity numbers the less "stable" the oil is. I really can't quote any specifics though, go look up and download "The Motor Oil Bible" it's good reading.
Seriously though the multi-grade oils require friction modifiers and such to give them their properties. The bigger split between the viscosity numbers the less "stable" the oil is. I really can't quote any specifics though, go look up and download "The Motor Oil Bible" it's good reading.
Race Director
Joined: Dec 2002
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
Originally Posted by nato
I thought at warm/running temps 5w30 and 10w30 both act like 30 weight oil and it wouldn't matter and when it's cold the 5 acts like 5 weight and the 10 acts like 10 weight so in the summer and all why would it matter which you ran?
Once they are up to temp, they are (in effect) the same oil.
The 5w just flows slightly better at extremely low temps.
Larry
Le Mans Master
Joined: Dec 2002
Posts: 6,715
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From: Santa Teresa New Mexico
Originally Posted by code5coupe
You are exactly right.
Once they are up to temp, they are (in effect) the same oil.
The 5w just flows slightly better at extremely low temps.
Larry
Once they are up to temp, they are (in effect) the same oil.
The 5w just flows slightly better at extremely low temps.
Larry
Team Owner
Joined: Apr 2004
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From: All great change begins at the dinner table Ronald Reagan
Originally Posted by elefkow
The GM book says to use 5W30 and thats what I use.
