lloaf

For a few months now, Mobil 1 10/30 has not referenced the GM 4718 Spec. The 5/30 still does. What gives ? By the way, I am talking about regular synthetic Mobil 1, not the extended performance stuff.

filmelf

My last dealer oil change they used 10-30 Mobil 1.

JC in XTC5

From Mobile Oil Website:

Mobil 1 10W-30 exceeds warranty requirements for gasoline engines where an API certified oil is specified. It meets:

• ILSAC GF-4 (API Certified - Starburst)
• API SM/SL
• GM 6094M/GM4718M
• Requirements for Diesel Powered Vehicles where an API CF or API CD is Recommended
• ACEA A1/A5, B1/B5

http://www.mobiloil.com/USA-English/..._1_10W-30.aspx

Don't see what the problem is. I've used 10/30 exclusively since I got the car 6 years ago, and there's virtually no difference between 5W and 10W-30.

Note: Mobile 1 Extended Performance Oil does NOT explicitly list the GM4718M spec, (5W or 10W). But we shouldn't be using that.

lloaf

Assuming the web-site is up to date, there should be no problem, although as we all know web-sites are not always up to date. My point is the bottles themselves used to specify 4718M, and they no longer do--even though the 5/30 still does, which I find odd.

EHS

If you continue to be concerned, switch to 5W-30.

Dave68

Actually, according to a Mobil 1 specialist I spoke to not too long ago, there is really no reason for anyone to switch from 5W-30 to 10W-30. In fact, he mentioned that engine wear is accelerated when 10W-30 is used (at startup) because even at 75 degrees F, 5W-30 flows more easily than does 10W-30.
This guy lives in Texas and is using 0W-40 Mobile 1.

JC in XTC5

OK, can someone explain how a 30 weight oil during warm startup temps wears more on one that has a lower cold temp viscocity? And if you look at the Mobil specs on 5W and 10W, how extremely small difference between the two specs translates to such a significant statement as that made above?

Dirty Howie

Does he own a Vette ?

Are you switching to 0-40 ??


DH

Dave68

Granted, the difference may be being able to run your LS1 to 200,000 miles vs 150,000 miles, but nonetheless, 5W-30 Mobit 1 is recommended for ALL climates. Those who "see" higher-than-normal oil temps (260+) may want to go to a 0W-40 oil, but there is no sound reason to think that 10W-30 is better at higher temps than a 5W-30 (same manufacturer).

Dave68

Howie,

My point was that even though he lives in an area that sees very high temps and often, he is using a 0W oil. For some reason, people look at the 0W or 5W and automatically think the oil can't protect the engine at high temps.
Remember too, that when GM tested the LS1 and LS6, they spent plenty of time in desserts where ambient temps often exceed 110F. The 5W-30 that our engines have from the factory was designed to protect at oils temps exceeding 260F, not for 24 hours of Lemans, but for the occasional high speed jaunt up a mountain when ambient temps are in the 90s or greater.

dave

JC in XTC5

A few comments regarding Mobile 1 Synth:

• 0W-40 does NOT meet GM4718M spec. Use at your own risk.
• 5W-30 and 10W-30 are virtually identical at normal operating temp.
• It's always recommended to choose an oil with the narrowest viscosity range for your operating temps.
• 5W-30 was identified by GM as the "preferred" viscosity to for slightly better EPA performance, not because it performs better overall.
• In normal summer temperatures, 10W-30 is a better choice over 5W-30.
• In winter temperatures below 0F, 5W-30 is a better choice over 10W-30.
• In either environment, both oils perform well beyond a normal mineral oil, i.e. 10W-30 pour point is -45C, 5W-30 pour point is -54C.

There is no scientific reason that 5W-30 will increase longevity of your engine over 10W-30. In fact, the narrower viscosity range of 10W-30 should have an advantage, albeit very slight when considering synthetics.

Dave68

This "viscosity range" issue is true of most petroleum-based oils, but is not true of synthetic oils in general.

Here's a quote directly from Mobil 1 via email:

From: Mobil Product Information <mobilproducts@ourdataworks.com> Date: Tuesday, March 22, 2005 7:56 am Subject: (no subject) > The 5W30 and 10W30 motor oil do not have the same pour point. The
> 5W30
> motor oil is lighter so it can be pumped easier through the engine
> at
> start-up which will decrease engine wear.
>
In my book the 5W30 has a 5 degree edge on the 10W30 motor oil when it comes to pour point. The pumpability of the 5W30 motor oil would also be easier especially at start-up."

The big fallacy, as I mentioned previously (and is obviously still being circulated) is that 10W-30 is a better oil during the Summer. This is absolutely not true. GM and Mobil 1 have stated that 5W-30 is the better YEAR-ROUND oil.

I guess some old theories about 10W-30 protecting better at higher temps never die..........

EHS

The temp debate is nice, but, then, for those of us who are "older" forum members, remember the issue with oil mileage........ and those pesky rings and recalls.... That's why I use 10W30.

Cheers!

gorillavet

Also folks with modified engines usually run 10W/30, i.e. cam/heads.

Dave68

Many years ago, manufacturing/machining tolerances and materials were not as precise as they are today. A factory LS1 has been designed and built to run with 5W-30 synthetic oil.
certainly, if your piston rings are severely worn and their diametral clearances are much greater than they were when new, by all means, throw 20W-50 oil in the crankcase. Keep in mind, though, that the viscosity of 10W-30 oil at normal operating temps is the same as that of 5W-30. With 5W-30, you get all the benefits of less startup wear with the same high-end protection as 10W-30. This is why many consider 10W-30 synthetic oil to be essentially, obsolete. I agree.

Not too long ago, I had a neighbor who used only straight 30W oil in his truck. He really believed that it was the best oil to use, despite his truck manufacturer's recommendation of 5W-30 oil. Was he surprised when his engine started burning oil at 80,000 miles? Yep! was I? Not at all.

EHS

Well, Dave, having been through this with a brand new C5 and the oil consumption that the brand new C5s were having back then (1999 through 2001), complete with the GM mandated dealer oil consumption test, I found that 10w30 just plain old burns less oil (about 1,700 to the quart).

Here -- refer to these TSBs for details: 01-06-01-011B and 01-06-01-023A.

And -- read this: http://www.rjsmith.com/gm-894549.html#top

As the bulletin says "Some owners may comment on higher than expected oil consumption. When checked the oil consumption could be in the range or 400-600 miles per quart...."

I prefer my consumption to be 1,700 miles per quart, personally, and I find 10W30 gives me that. 5W30 doesn't.

bdiddo

not an expert by any means but as an owner of a 2001, since swithcing to 10W30 I no longer burn oil like I use to (this is with header/cam combo). The proof is in the pudding

Dave68

I guess in a few years, you can switch to 20W-50 and after 10 years, use straight 60W or maybe gear oil......

Seriously, using oil that is thicker at startup temps is not a permanent solution if you plan to keep your car for a long time. It's kinda like using StopLeak in a leaking radiator. Sooner or later.........

EHS

Please tell that to GM and even people like Ferrari, or else send me a check for $9,500 for a new motor, built to better tolerances.

crawfish333

And the 2002 owners manual says:

Drumroll......

"As shown in the viscosity chart, SAE 5W-30 is best for your vehicle. However, you can use 10W-30 if it is going to be 0 Deg. F (-18 deg. C) or above.
These numbers on an oil container show its viscosity or thickness. Do not use other viscosity oils such as SAE 20W-50."

I use the Mobil 1 10W-30 in my C5. Believe me, it will never get down to zero here in Louisiana, if it does hell will also freeze over.