10w30
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6th Gear
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10w30
I recently purchased a 2015 C7 with 32,000. After I purchased it I requested the inspection information that they had performed prior to sale. I noticed that they changed the oil and used 10W30. I reached out and the response was either 10W30 or 5W30 synthetic work. I feel more comfortable with the full synthetic. Is there any ramifications of switching it back to the full synthetic?
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Apr 13, 2026, 09:43 AM
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St. Jude Donor '12 thru '17
I recently purchased a 2015 C7 with 32,000. After I purchased it I requested the inspection information that they had performed prior to sale. I noticed that they changed the oil and used 10W30. I reached out and the response was either 10W30 or 5W30 synthetic work. I feel more comfortable with the full synthetic. Is there any ramifications of switching it back to the full synthetic?
There are no ramifications from switching back to full synthetic. While GM "recommends" full synthetic, the requirement in your Owner's Manual is that the oil meet the dexos 1 standard. Far too many Corvette owners overthink oil, including type, viscosity, change interval, etc. Just read your Owner's Manual, do what it says, and enjoy your new C7.
.
Melting Slicks
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5w30 or 0w40 full synthetic are appropriate use cases for the C7. I will personally be going with 0w40 for my next oil change.
Drifting
Joined: Jun 2013
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From: Iowa
I would switch to the recommended 5w30 or 0w40 full synthetic ASAP. Could you be fine w/the 10w30 possibly but why chance it? I'd say try to take it back to the place you bought it from and have them do it since it was their screw up but it sounds like they're incompetent so either do it yourself or take it to a reputable shop that will put the correct oil/filter in it.
Team Owner
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St. Jude Donor '12 thru '17
I recently purchased a 2015 C7 with 32,000. After I purchased it I requested the inspection information that they had performed prior to sale. I noticed that they changed the oil and used 10W30. I reached out and the response was either 10W30 or 5W30 synthetic work. I feel more comfortable with the full synthetic. Is there any ramifications of switching it back to the full synthetic?
There are no ramifications from switching back to full synthetic. While GM "recommends" full synthetic, the requirement in your Owner's Manual is that the oil meet the dexos 1 standard. Far too many Corvette owners overthink oil, including type, viscosity, change interval, etc. Just read your Owner's Manual, do what it says, and enjoy your new C7.
.
Last edited by Steve_R; Apr 15, 2026 at 10:29 AM.
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Some 10W30 motor oils meet Dexos Requirements and may be acceptable. C7s can run a non-Dexos-rated oil, Mobil 1 15W50 oil, when on track. The downside of using it on the street is higher fuel consumption and a higher likelihood that the catalytic converters could be damaged. I used to leave the Mobil 1 15W50 in between track sessions since changing 10 qts of oil before and after a track event got expensive. The 0W40 Dexos-rated oil was developed for track/street usage.
Bill
Bill
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Joined: Apr 2014
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I recently purchased a 2015 C7 with 32,000. After I purchased it I requested the inspection information that they had performed prior to sale. I noticed that they changed the oil and used 10W30. I reached out and the response was either 10W30 or 5W30 synthetic work. I feel more comfortable with the full synthetic. Is there any ramifications of switching it back to the full synthetic?
Le Mans Master
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From: Loveland
The latest, updated, recommendation from GM, oil for the C7 is the Mobil 1 0W-40 Supercar oil. There are many really cheap oils that many people use. It's up to you. You can always change the oil without any issues.
Pro
Joined: May 2022
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From: Peoria, Arizona
I recently purchased a 2015 C7 with 32,000. After I purchased it I requested the inspection information that they had performed prior to sale. I noticed that they changed the oil and used 10W30. I reached out and the response was either 10W30 or 5W30 synthetic work. I feel more comfortable with the full synthetic. Is there any ramifications of switching it back to the full synthetic?
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If you purchased at a dealer, I would take it back and request an oil change using a full synthetic 5W-30 or 0W-40 Dexos rated oil since that is the GM specification. Failing that, I would get the oil changed as soon as possible to one of the afore mentioned types. Filter change at the same time.
Drifting
Joined: Dec 2019
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From: Blacksburg Va
It is summer coming right up so I wouldn't be concerned about the 10-30. It would be nice to confirm exactly what make model/oil was used so you can decide on whether to leave it in there. But it's not like running even dyno oil for a few weeks or months is going to blow up the engine.
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It is summer coming right up so I wouldn't be concerned about the 10-30. It would be nice to confirm exactly what make model/oil was used so you can decide on whether to leave it in there. But it's not like running even dyno oil for a few weeks or months is going to blow up the engine.
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I would switch to the recommended 5w30 or 0w40 full synthetic ASAP. Could you be fine w/the 10w30 possibly but why chance it? I'd say try to take it back to the place you bought it from and have them do it since it was their screw up but it sounds like they're incompetent so either do it yourself or take it to a reputable shop that will put the correct oil/filter in it.
Drifting
Joined: Jun 2019
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From: near philly
in his case it shouldn't really matter that much, and the 10w-30 won't really matter as long as it's changed before winter (if he even drives in winter)
Melting Slicks
Joined: Dec 2004
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The C7 engine has tight tolerances and it was designed for full synthetic oil 5W 30. In addition, 0w40 is acceptable. If it was my C7, I would get that oil out as soon as possible. As long as I am able bodied enough, I will always change my own oil. I have had some bad experiences with dealerships letting their newbie mechanic change oil only to see that they overfilled it by over two quarts in my Honda 20 yrs ago. I personally know of a new mechanic who changed all the fluids in a customer‘s car only to forget to put oil back in the engine and then he started it up and it made a cluttering noise and a senior mechanic walked by and casually said: It will run better with oil in it.
Race Director
Joined: Apr 2014
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From: North Texas
true, but coking is much more of a problem with turbo motors only because of the turbo oil supply and the blazing heat turbos see
in his case it shouldn't really matter that much, and the 10w-30 won't really matter as long as it's changed before winter (if he even drives in winter)
in his case it shouldn't really matter that much, and the 10w-30 won't really matter as long as it's changed before winter (if he even drives in winter)