Appropriate Engine oil for C6, please advise...

[Tak]

First of all, hello everybody and great site. Have been reading the forum for a while now, and i must say there are people here that know their stuff, really really impressed! Decided to post for help...


Ive been searching the net and forum for opinions on engine oil for the C6...
Here goes:
The problem is, you need the thin oil (5w-30 or 10w-30) for the LS2 engine, for the tight bearing clearances etc., but its a performance engine that works at high temps when beeing pressed hard. Wont the oil thin out too much under harsh conditions and lose its protecting abilities?

Another thing, how can GM give a one fits all oil specification for their cars

? i mean this is the same for all weather conditions and variations? There are cars that start cold at -20C (-5F) and for cars that never deal with under +15C (60F) temperatures, and then where im from it goes up to 45C (113F) in the summer and almost never below 15C.

Anyway, lets say that 10W-something is mostly ok for cold starts, how about the other unit? If the oil is too thick like 15W-50 then it eats away horsepower from the crank as the moving oil is thicker. So some reccomend thicker oil for older engines to protect them. I owned a nissan Skyline GTR and was told to only use 15W-50 in my conditions so that the oil would keep its viscosity at high working temps... but then again that was turbo...

The mobile 1 5w-30 used in my opinion is the reasoning for such oil consumption present in the case of the C6. Maybe some other fact were taken into account by GM when choosing the oil, like: Fuel consumption, performance figures, emmisions, better prices from mobil?

QUESTIONS:
1. in hot conditions, is the 10w-30 going to protect enough my engine when i push it? (keep in mind i care more about my engine than what is written in the manual warranty wise) and dont mind the 20 dollars more per oil change,

2. Mobil 1 is generally acknowledged as one of the best fully synthetic oils, anybody heard about how others like redline or 76 do in corvettes? (someone i know who has a tuning garage uses only 76 lubricants in his vehicles. im just really asking as i dont know if this is an expensive oil) So please advise on this 76 lubricant if any have used it or heard about it


All advise is greately appreciated

Thanks,

I hope there are others with these questions at mind and that im not just bringing up a subject boring to most.

 

[ruking77]

On the 2001 C5 (Z06) in addtion to oem fill 5w30 Mobil One, the tech data and owners manual does say it has to meet the GM 4178 M specification. I have been running Mobil One 5w30 for app 70k miles with 15,000 mile OCI's. The thing still runs like the proverbial top.

 

[GMBoy]

I have always used Mobil 1 in my Corvettes. 5W/30 in winter and 10W/30 summer. It is the factory fill and meets the 4178 requirement like ruking77 said. If you choose to go another route, be sure that oil meets the GM requirement. GM went to MObil 1 oil because they found that syn lubes work so much better that they could eliminate the oil cooler and save weight and costs not to mention the increased oil leakage possibilities. This was all done when the LT-1 came out in 92. When I was a part of the C6 launch an engineer told me that his biggest fears where of owners using the wrong oils. Well - I know there's plenty of vette's going to "iffy lube" who knows what damage is being done!

My final word - stick with any oil that meets the GM requirement. I just prefer Mobil 1.

 

[hotrod]

Many on Vettnet swear by Redline.

 

[forcedtalon]

Red line would be the best oil for this motor (5w30)
If your going to road race it at the track then go with a 10/30 (in the summer) but run the 5/30 year round on the street.

 

[SSDude]

I would run the following oils:

GC
Redline 5w-40

Mobil 1 Truck and SUV 5w-40

Synergyn 3w-30

Amsoil 5w-40


All of the above oils will protect your engine adequately. If you drive hard you will need the added protection that these oils will provide.

 

[NewC6]

Welcome Tak, glad to see there is another C6 owner on the board.
As to your oil question, you will get a number of varied answers. Hope you find one for your situation. Me, I will be running AMsoil or GC in my C6. Probably the 10w-30 Amsoil and of course GC is only 0w-30.

Good luck and

 

[forcedtalon]

You dont want a thick oil. You want an oil with high quality antiwear agents. Todays engines have tigher bearing clearances requireing thinner oils.Thus is the reason why is comes stock with the mobil 1 5/30 .

 

[Tak]

Thanks for all the reponses, really is a great forum


Quoting GMBoy: "If you choose to go another route, be sure that oil meets the GM requirement. GM went to MObil 1 oil because they found that syn lubes work so much better that they could eliminate the oil cooler and save weight and costs not to mention the increased oil leakage possibilities."

the Z51 C6 does have an oil cooler! I think i will be going with 10w-30 too as it gets hot here...


NEWC6, really good to see more C6s. what colour spec is urs?


Anybody with used oil analysis done on an LS2 engine vette? i read some data off the board like: "Mobil 1 5w30's weak 3.1 HTHS number just doesn't appeal to me at all." and: "I just think the factory 5W-30 (10.0 cSt) is a little on the thin side." so all this keeps me skeptical. should i go to mobil1 10w-30? does anybody have the HTHS and cSt figures on it?



and just now, i go and find this... (from a thread NEWC6 started

code:
--------------------------------------------------------------------------------

GF-4 M1 5w30 64.8(cSt@40ºC) 11.3 (cSt@100ºC) 3.09 (HTHS Viscosity,mPa·s@150ºC) VI 169


aaaaaaaaaaaahhhhhhhhhhh, going crazy!!!!!!!!!


ALSO!!! anybody EVER use 76 lubricants, or even know somebody who does???


thanks again everyone

 

[surfstar]

To make you crazier, the 100*C cst for M1 10w30 is only 10.0 while the 5w30 is thicker at 11.3

If you want the best protection from a 30wt, I'd recommend redline or GC (german castrol).

 

[99]

The LS2 is just a slightly evolved LS1 with more cubes-nothing special per se once you get past the naming nomenclature. I'd stick with the Mobil 1-just go thicker, like say their 5W40 if the oil consumption bothers you. Keep in mind most all newer hi-po engines use low tension rings-they'll cause oil usage. Also, a engine will use oil while it "breaks in" so give it a few thousand miles before passing judgement.

 

[99]

http://www.gmhightechperformance.com/features/0405htp_ls2/

 

[buster]

Some great info from an engineer about oil consumption. I would take his word.

quote:

---

Some oil consumption is of absolutely no concern to me, personally. Niether is it a concern to the engineers that design and develop them. Mostly it is just an inconvenience (having to add oil occasionally). Only car owners seem to be upset by oil consumption.

I think most people's analysis of "why engines burn oil" is based on the (false) idea that an engine shouldn't burn ANY oil and if it does burn some oil then something "must" be wrong and they invent all sorts of logic to explain why it happened. Most all of it is nonsense.

Most high output engines will always use some amount of oil as keeping the top rings lubricated at high loads and high RPM is impossible without loosing some oil past the rings. Plus, multivalve engines need to keep all those valve guides/stems lubricated and that is only accomplished with "total loss" oiling.

Many engines have very aggressive cylinder wall finishes to maintain oil on the cylinder walls to keep the rings lubricated at high specific power levels. This often leads to high oil consumption and variable oil consumption from engine to engine. None of them are "good" or "bad" ..... just some of them use more oil than others.

If the engine is not smoking I would say that the oil consumption (no matter how high it is) is fine and that nothing is wrong. If the engine suddenly starts to smoke and use oil then something obviously changed or failed but low levels of oil consumption are perfectly accecptable.

BMW had such high oil consumption on some of their M engines that they caution to check the oil at EVERY fillup on the autobahn type driving as the engine can run low on oil in a slightly longer interval. They actually replaced engines that failed from oil starvation due to the high rate of oil consumption that was "normal" due to the aggresive cylinder wall finish and low tension ring pack.

---

 

[ruking77]

I would agree with the take on the V-8 LS1 and LS2 consuming oil. Mine consumes app 1 qt per 5,000 miles. So over the course of a 15,000 mile OCI, we are talking 2-3 qts. While I wish it consumed NONE, it is just the nature of this engine design. So I just carry 2 extra quarts. If I happen to start off on a long trip low on oil, the first will top it off and the 2nd qt will get me back home!

 

[Mr Nice]

Tak,
Just use Mobil 1, Amsoil or GC. They are all excellent oils.

Ruking77,
Did GM 're ring' your LS6 ?

 

[ruking77]

No, for some funny reason it was not affected with the "issue".

This is purely a SWAG and hindsight 20/20, but I did the break in always under "load" and didn't go full redline much with out a load till after 1500 miles.

Most "re ringers" had consumption of 1000 miles and LESS!? I think 1500 miles between quarts qualified one under warranty for the oil test. What has been the history with any of yours?

Again in hindsight perhaps I should have tortured this puppy and gotten them to do the "re ring" on GP. The thought of them tearing down an almost brand new engine and not knowing if it would really turn out well was enough to give me pause. I actually talked pretty extensively with my local Corvette tuner. Given what he saw of the car and what I was telling him he didn't recommend getting the re ring job.

More on point I have seen informal polls that fully 68% of Corvette owners who participated in the polls start with and stay with the Mobil One, and 5w30. If I remember correctly 15% either tried or went to 10w30.

[ December 03, 2005, 11:38 AM: Message edited by: ruking77 ]

 

[buster]

What about the idea that no oil consumption isn't a good thing? You do want to have some oil consumption of some degree to help lubricate the upper ring area and valve stems.

 

[Ryan00TJ]

I've been beating on my LS1 since it was broken in at around 1K miles. At 4K miles I had it broken apart installing an LS6 grind camshaft. Now with 27K on the 02 Shortblock it's on it's 3rd different cam and 1st set of Stage 2 aftermarket heads. It's see's alot of high rpms when fully warmed up street driving and around 10-40 track runs per year. I've never gone much above 4K mile OCI's but the oil level does not move on the dipstick even after 5-6 back to back runs at the track. I guess i'm lucky in that aspect. The late 01 and all 02 LS1 Fbody's got M1 5W-30 as the factory fill and I stuck with it until 5K miles. I then switched to Schaeffer 10W-30 for a few OCI's. I then started using straight Schaeffer 15W-40 during summer and a 10W-30 15W-40 mix during the winter. My lowest wear numbers came from straight 15W-40 with lotsa track runs on that particular sample. I've now depleted my Schaeffer stock and will be trying Mobil 1 5W-40. It has all the right stuff to keep a LS1/2 in the safe zone IMO. High HTHS, Good additive package along with resistence to thinning and breakdown.

Here are my UOA's http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=002245

 

[Tak]

Thanks to everybody for their posts!!! for the UOA, the small block engine explanation, the oil consumption matter and everything...

VERDICT:
I have spent hours and hours on the forum trying to decide what seems best to do. Apparently, any good oil (M1, redline, GC etc) is an ok choice, and the difference is minimal... BUT take it back to the factors in my situation, and i have made a choice...

1. I live in mainly warm summer conditions and the car will never start in under 10 degrees C, 90% will be over 18C... SO i choose to go for a slightly thicker oil with higher HTHS not caring too much about the winter rating.
2. I will be changine the oil at 3k anyway, so i dont mind about the oils life longevity, making a good excuse for many UOA

3. Dont want to go too thick on the oil because of tight bearing clearances, and dont want to lose any valuable HP - will be keeping an eye on the oil temp and if is needed will move up a step

The oil with all all the factors pointing to it is redline! The two choices are 5w-30 and 10w-30... Both are thicker than the M1 and both have higher HTHS. They actually have all top end properties practically the same (HTHS etc) but a lower viscocity index for the 10w-30 leading to poorer winter protection.

BUT: what i am interested in is not the winter side of it and the operating temperature side. as they have the same properties here, it means there is going to be less additives to the oil to increase the temperature variation capabilities and more actual OIL and better lubrication!!!

This gives a worse VI but it doesnt affect me in my case

So thanks everybody for helping me make this decision, will post the UOA starting next oil change and we'll take it from there.

Thanks again

 

[NewC6]

Tak,
Sorry for the posting delay. My C6 is a base model A4 with performance gearing. Black with Cashmere interior. Love it to death.
Congrats on your quest. I am happy with the GC or Amsoil. I am sure Redline will do well in your car.