I just bought a used C5 last weekend from a dealer. The car had always been serviced with Mobil 1 and it has 100,000 miles. Prior to my picking the car up they did an oil change on the car. As a Chevy dealer I would have assumed they would know to use synthetic oil. After getting it home I noticed the oil change sticker they had put in the windshield indicated conventional oil. I called the dealer this morning to see if they had simply checked the wrong box on the sticker or if they really put the wrong oil in it. As it turns out they put in non synthetic oil. I have an appointment to get it changed but I'm wondering what effect the use of the improper oil will have. It has been driven about 75 miles with the non synthetic.

 

Don't give it another thought.

 

There won't be any problems at all. Just make sure that the oil change guy knows what to use. The oil fill cap should be a good visual clue to him.

I would also ask for a new filter at the same time. It holds a good half-quart.

 

 

It's gonna blow up!!!



























































it's fine just drive it until you get it changed no biggie

 

I would be fearful of using them for any future repair work though.

 

Obviously you're not worthy of owning it, so you must now sell the car. How could you let such a terrible catastrophe occur?

 

Thanks for the response and glad to hear it's no big deal. To be clear the oil was changed at the dealership prior to my buying it. A couple of guys in my Corvette club said never put mineral based oil in thus my reason for the post. This is my first experience with an aluminum block so I wanted to be sure. I've used nothing but conventional oil in my older Vettes for years but I wasn't sure about a C5. Thanks again.

 

No problem at all. However I would go back to the synthetic meeting GM4718M at the next oil change.

There has been some confusion frequently at the dealers because GM4718M has been replaced by the new Dexos specs. The dealers generally use an oil meeting the Dexos spec. However the two specs are different. There are some non synthetics and synthetic blends that can meet the Dexos spec even if they don't meet the GM4718M spec.

GM went to the GM4718M spec back when the C4's came out with the LT1 motors. At that time the reasoning was that the synthetics meeting GM4718M spec could survive without an oil cooler that was discontinued on the C4's at that time.

I don't know the heat characteristics of the LS motors to know how quickly an oil will break down, but I would suggest going back to a synthetic.

Good Luck.

 

away from stealer service departments.

 

Funny. Truck engines with the alum blocks don't say Mobil 1 on the cap. Not unusual to see them go past 200k miles.
They going to do the oil change for free?
Ron

 

Well these "club" members dont seem so knowledgeable. Good thing you asked here. Dont worry man, its still a good 'ol Chevy V8. Any good oil, regular maintenance and itll run forever.

 

I've used conventional oil several times in my car with no apparent ill effects. I have however noticed that I will consume 1-1.5 quarts between changes with conventional, and with M1 Syn I don't lose enough to notice on the dipstick. That's enough justification for me to keep using the M1.

 

I think the advantages of an aluminum block would be weight and heat transfer, but you still have steel on steel on piston travel, valve and bearing surfaces. Lube requirements would be nominally , if at all affected by aluminum block?

 

Idiots
Engine is just metal like any other it doesnt know what youre putting in it
Amsoil syn or house brand cheap dino oil it will run just fine.

 

Just to be clear , the synthetic oil spec has nothing to do with the engine being aluminum. I have always believed in using Mobil 1 in the last C5 that I had and the current C5 that I have because it was factory filled and I never had any problems ( must be the engineer in me ,if it aint broke etc...). The other thing to consider is that GM now abides by the Dexos spec and if you check out the oils listed as meeting the Dexos spec you notice that they are not all synthetic so that may be why the Chevy dealer used the oil that they did! http://centerforqa.com/index.php?opt...d=31&Itemid=74 They also state that Dexos is backward compatable. I still plan to stick with Mobil . Best of Luck!

 

Sell it immediately!

 

Mineral oils and synthetic are compatible and you will have no ill effects from running non-synthetic for a short while. I wouldn't take the car to the track or run it to really high oil temps while you have mineral oil in it though.

 

As one of the petroleum chemists that helped run the fist engine sequence tests on Mobile One and many hundreds of tests on others oils I can tell you not to worry at all. Yes, Mobile One is a far better oil than standard oils, but standard high-grade oils are okay for a short time, especially in a C5 with more than 30,000 miles on it. No problem mixing oils, they will blend without a problem. But I do agree with you on the choice to go with Mobile one. I do in every car I have had since the product first came out and we tested it for use in military vehicles for the Army. It is the battle-field oil of choice for a good reason - under fire you do not want oil problems. It flat out is better. It works. 400% improvement in shear strength is just one example. Higher temp oxidation is another, etc. etc. But I will not bore you with more specs. No hurry, top it off with a quart of Mobile one in it when you can, when you change the filter for example. Or just drain it and refill it, but it will not hurt you in the short term. But I would not go more than 2,000 or 3,000 or so miles with the standard oil in an older engine. But others say don't go 1,000 and others say no issues at all in an older engine. No real data on the difference between these oils for a duration of X miles on an engine that is already broken in and has many thousands of miles. But I know your passion. For all my gasoline engines regardless of what they are (except marine) I use only Mobile One. But most other syn oils are probably just as good. I only say Mobile one as I was personally involved in these tests and I personally wrote the purchasing specs for this oil for many organizations back when this oil first came out. Yes, I am that old. Nick

 

Welcome to the forum Nick.

Solid, level-headed feedback and commentary is sometimes a rarity here, especially in these (what seem like), never-ending oil threads. Seems like it's one of the favorite "mystery of life" topics.

Oh, and don't worry about the "old" thing. There's a lot of that going on around here.