[Z06] Mixing oil weights?
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 1,205
Likes: 5
From: Jupiter FL
Mixing oil weights?
Is there any problem with mixing weights of Mobil 1 synthetic motor oil? I have a case of 5W30 and a case of 10W30, both Mobil 1. I'm doing an oil change and filter on the '03 Z, and might need a quart or two more than a case. If I put the 5W30 in the engine, is there any problem with adding a quart or two of 10W30?
Heel & Toe
Joined: Jun 2006
Posts: 24
Likes: 0
See:
http://www.mobiloil.com/USA-English/...bil1_5W-30.asp
and
http://www.mobil.com/USA-English/Lub...l_1_10W-30.asp
According to the Mobil 1 web site they both meet GM4718M. This is the requirement for oils for your Corvette. However, I have new bottles of each Mobil 1 5W-30 and 10W-30 in my garage and only the 5W-30 lists that it meets GM4718M on the bottle. So the question is: Why does their web site say the 10W-30 meets GM4718M and the bottle clearly does not? I would think that they would want to state same on their bottle.
According to the factory manual page 0-42 and 0-43:
"Look for and use ONLY the oils that meet GM specification 4718M."
"The recommended SAE engine oil viscosity is 5W-30, however, if temperatures are above -18degrees celsius (0 degrees F) 10W-30 may be used."
Many, who live in warmer climates, use 10W-30 Mobil 1 in their Vettes. Some use 5W-30 in the winter and 10W-30 in the summer. If you can use 5W-30 in the winter and 10W-30 in the summer then they would have to be compatible as one can never drain all the oil, when changing oil.
I know of no problem with mixing the two. I have never done so in my Z06 but have done so in my Volvos when I did not have enough 10W-30 in stock.
Cheers!
Jim
http://www.mobiloil.com/USA-English/...bil1_5W-30.asp
and
http://www.mobil.com/USA-English/Lub...l_1_10W-30.asp
According to the Mobil 1 web site they both meet GM4718M. This is the requirement for oils for your Corvette. However, I have new bottles of each Mobil 1 5W-30 and 10W-30 in my garage and only the 5W-30 lists that it meets GM4718M on the bottle. So the question is: Why does their web site say the 10W-30 meets GM4718M and the bottle clearly does not? I would think that they would want to state same on their bottle.
According to the factory manual page 0-42 and 0-43:
"Look for and use ONLY the oils that meet GM specification 4718M."
"The recommended SAE engine oil viscosity is 5W-30, however, if temperatures are above -18degrees celsius (0 degrees F) 10W-30 may be used."
Many, who live in warmer climates, use 10W-30 Mobil 1 in their Vettes. Some use 5W-30 in the winter and 10W-30 in the summer. If you can use 5W-30 in the winter and 10W-30 in the summer then they would have to be compatible as one can never drain all the oil, when changing oil.
I know of no problem with mixing the two. I have never done so in my Z06 but have done so in my Volvos when I did not have enough 10W-30 in stock.
Cheers!
Jim
Last edited by JTS/Z06; Jul 22, 2006 at 04:39 PM.
Le Mans Master
Joined: Nov 2001
Posts: 6,984
Likes: 0
From: Central Coast CA
There are no problems doing this. Why would there be? As long as the oil is the correct rated oil all is good. It will however slightly change the viscosity of the oil to somewhere in between the two.
Melting Slicks
Joined: Oct 2000
Posts: 2,491
Likes: 1
From: prescott AZ
I called Mobil at 1-800-ASK MOBIL and asked if I could mix 3 qts of their 5-30 with 3 qts of their 10-30 and they said my engine would explode............. just kidding. They said it would mix fine and I would have a 7 1/2-30 wt oil. This is what i use as i do not feel comfortable with a 5-30 oil. I believe GM wants you to use the 5-30 for C.A.F.E. standards so they can claim a mpg that lets them pay less tax as per the CAFE standards.
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