Mobil 5w30 here!!

 

Is there a 15W50 that meets the GM spec? If not:
Notice: If you use oils that do not have the GM4718M Standard designation, you can cause engine damage not covered by your warranty. That means, no warranty, and an oil that is as heavy as 15W50 would be easy to distinguish between a recommended oil, and an oil analysis would verify it. Thus, no warranty on engine or internal components.
In addition, the majority of engine wear happens at startup, and a 15W oil take a while, even in 80 degree weather to lubricate the top of the engine.
You car, but if the engine blows, don't blame GM.

 

 

thats why i do it..

 

From:
http://www.idavette.net/hib/C5diy/c5diy1.htm

"The reason GM recommends 5W-30 is it's the politically correct choice when fuel mileage is a prime consideration. The U.S. Environmental Protection Agency, which oversees fuel economy standards for cars sold in this country and believes 5W-30 oil is a significant energy conservation measure, pressures car companies into 1) using 5W-30s in new vehicles and 2) marketing them to service customers. In response to this pressure, many years ago a policy was made by GM at the corporate level that, with few exceptions, the recommended oil for all passenger vehicles be 5W-30.

When you read the "Maintenance and Lubrication" section of the 1997 Corvette Service Manual carefully, you soon find there are alternatives. The book states on page 0-47, "The recommended SAE engine oil viscosity is 5W-30, however, if the temperature is above -18¡C (O¡F) 10W-30 may be used." Not only is this true for C5 but the same or similar language appears in owner's or service manuals going back a decade or more.

While we dispose of used oil and filters responsibly, recycle our cans and plastic and keep our room air conditioners set for 78¡, the Technical Staff of Vette Magazine cares little about the fraction of a percent better fuel mileage we supposedly gain with 5W30 oil in our Corvettes. It is our opinion that high-performance engines regularly operated in above 0¡F outside temperature and in their intended duty cycles will maintain performance longer if an oil of different viscosity range is used.

Any 5W-30 engine oil, including the synthetic in C5s, uses chemical additives, called "viscosity-index (VI) improvers", to widen its viscosity range enough to make it a 5W-30. VI improvers contribute little to lubrication and can make a "multi-vis" oil less effective at high temperatures than an oil without them. This can become a problem when the oil is under high shear loads at temperatures above 225¡F. It becomes a potentially damaging problem when oil temp. approaches 300¡F. If your oil temperature in the pan is 250¡F or above, bet that oil temp in bearings is approaching 300¡. Near the piston ring lands and the upper sections of the cylinder walls, it is that or above.

Another characteristic of a 5W-30 that can be a problem in severe service is a relatively high evaporation rate at high temperatures compared to lubricants of more narrow viscosity range. A higher evaporation rate contributes to increased oil consumption and substandard lubrication in areas of high temperature.

There are no VI improvers in quality, 10W-30, synthetic engine oils and their high-temperature evaporation rate is less. Thus, 10W-30 synthetics are better lubricants in severe duty applications. For that reason, we recommend that any C5 owner, and, for that matter, the owner of any Corvette built since GM began telling us to use 5W-30Ñput a synthetic, 10W-30 oil in their engine.

A good choice is Mobil 1, 10W-30 synthetic."

 

Thanks for the info, I think I'll be running 10w30 Amsoil.

 

My car is only used in the warmer summer weather. It's not like it needs 5W-30 so it'll crank and get up into the engine quicker.

10W-30 is just a bit heavier and I like to think gives better lubrication when it starts cold.

My 2 cents ... Ron ...

 

I run German Castrol Syntec 0w30. My oil analysis results have been significantly better than any other reports I've seen for the LS1 engine. Mobil 1 (of any viscosity) doesn't show anywhere near as low engine wear as GC 0w30 does.

 

I would be more inclined to say that from what you can determine you think GC shows less engine wear. But what you don't know is if the GC is as good at carrying metals in suspension as other oils. It could be that Mobil1 just does a better job of suspension while GC is re-depositing the metals in other parts of the engine. An oil with no suspension capability would look brilliant.

 

Mobil 1--5w 30. For 6 years--no problems..

 

This is not the case here though, GC is simply a much better built oil, which is why it passes so many more strict European specs that M1 5w30 cannot pass.

I have my oil analysis results interpreted by Terry Dyson, who is well known as being the #1 expert at reading oil analysis results. He's been doing it for over 20 years now. He assures me this oil is the real deal, it's not "hiding" wear metals and depositing them inside the engine. This oil is simply very good, period.

 

I find this debate very interesting.
Prior to 10W30, people swore by 10W40. Prior to that people swore by straight 30 weight. Then you've got the 20W50 crowd.

Have we got any 5W20 fans?

I use 5W30. I've also used M1 0W30. No problems.

 

10W-30 for me being that I live in South FL.

 

I can't add anything more!

 

10w30 Mobil 1 in my wifes stock 98 and 5w50 Mobil 1 in my 2001

 

10-30w because of the temps here in AZ.

 

Ah! The old viscosity debate. I have seen what thicker oil can do to an engine. Glaze the cylinders. Not a good thing. And thin oil will not protect the cylinders. So that's why I stick with the recommended viscosity. If your in extremely high temps get your oil analyzed and make your determination from that. My .02

 

I'm with you....... so many just seem to be "locked in" to Mobil-1, I have to admit, their PR program is excellent, and the oil is good. But if they looked at the situation objectively, with an open mind, there's a very good chance they'd run the GC. But oh well, to each their own. I just hope they sell enough to justify keeping the GC available here, in the US.

PS: Tip: if you're going to stick with M-1, at least consider the European Formula 0-40 M-1 (it's head and shoulders above the std/US Mobil 1 in performance). You'll find it at Advance Auto Parts

 

I've stayed with 5w-30 for the same reasons as most .... it's what's recommended.

 

http://www.idavette.net/hib/C5diy/c5diy1.htm
Good info on why 10/30 might be better than 5/30. I run 10/30.
Terry