Plasticman

Using the "optional" 10W-30 Mobil 1 (for my 2003 C5), and noticed that the container does not have the GM 4718M spec (only has the GM6094M spec, plus the Chrysler MS-6395 specs listed).

Going to Mobil 1 website, I see that the Mobil 1 10W-30 is approved for both GM specs (GM 4718M & GM 6094M).

Anyone know why I should not use this oil? Or run into this before?

Forgive me forum members, for I have sinned (again).

Plasticman

Last C5

No reason not to use it. I run it in both the vert and the track car.

TEXHAWK0

GM just wants you to use the "energy saving" 5W30.

Plasticman

Don't like the breakdown of the increased viscosity index improvers in the wider range 5W-30, and here in central Florida we never see down below 20F, so prefer to use the (still GM approved) 10W-30 Mobil 1. Besides, the 10W-30 will help keep the cold engine piston slap gremlins away.

Just wondering why the Mobil 1 does not list the GM 4718M spec on the container (but is listed on their website 10W-30 spec sheet).

I guess an email to Mobil 1 is in order.

Thanks,
Plasticman

Dave68

I spoke to a Mobil 1 technical rep a while back and he told me that 10W-30 oil in synthetic form is essentially, obsolete. There is no reason why anyone should need this viscosity, since 5W-30 Mobil 1 protects (flows faster) better at startup temps and easily matches high temperature performance.

And contrary to the tale of increased viscosity index improvers , synthetic oils like 5W-30 Mobil 1 do not inherently require index improvers as do non-synthetic oils.

The Mobile guy went on to say that even in Texas, he himself uses 0W-40 Mobil 1. 10W-30 is sold only because some people believe that it is somehow preferable over 5W-30, 0W-30, and 0W-40.

jrose7004

It will be fine to use!

itzza427

I can see no problems,,but really what difference will a + or - of 5W make?? Just curious did the rep say whether 0W40 met the GM specs??

mellowyellow01vert

I am in Florida also and I use a 10w-30 syn in my '00 and '01 Vettes. Over 150K on my '00 and 32K on the '01.

Dave68

Although the Mobil 1 0W-40 is factory fill for some models of Porsche, BMW, and Mercedes, it does not carry the GM4718 spec. The Mobile rep did not mention the type of vehicle he had, but he did say that most engine wear occurs at startup, even at 70 degrees F. It is therefore a good idea to use a 5W-30 vs a 10W-30 synthetic oil.

rws.1

In a synthetic engine oil 5W 30 will stay in grade as long as 10W 30.
5W30 provides quicker lubrication, better fuel economy and more HP.
I don't know why anyone would use 10W 30 unless they couldn't find the 5W 30.

Tom/99

I use Mobil 1 10W-30 in both of my Corvettes, no problems. I like it better here in Houston, with the 100 degree summer heat.

Plasticman

Response from Mobil:

"Our Mobil 1 5W30 and 10W30 bottles carry the latest GM spec of 6094M. Both of these oils meet 4718M, and 6094M."

Just wondered why the 10W-30 container does not have the GM 4718M spec listed, and they did not answer that part of my question.

Plasticman

10U 99

Mobil will continue to sell the "obsolete" 10-30 as long as there is a demand for it. I run it in 3 vehicles and don't plan on changing

Slow Z06

that reminds me, I need to change my oil. Got 1200 miles on it.....


oh, I use 10-30 as well

Dave68

I think many people mistakenly believe that 10W-30 somehow provides better protection in high-temperature environments. That, of course, is completely incorrect. Just 20 years ago, some folks used only straight-weight 30 oil, thinking it was better than the multi-viscosity oils in hot climates. It took quite a while for that theory to die.

427435

This is the same thing that my professor told us in one of my "Internal Combustion Engine" courses years ago. Here are the viscosities of a couple of Mobil 1 oils that I got a few years ago from Mobil.

Temp------5w-30------15w-50

-20----------6284--------21,852
0------------2129---------6462
25------------697---------1836
32------------531---------1348
50------------281----------657
100------------71----------138
150------------27-----------46
175------------18-----------30
200------------13-----------20
225------------10-----------15
250-------------7.6---------11.1


A 10w-30 oil's viscosities would fall about half way between the ones above at the colder temps and end up being the same as the 5w-30 oil at operating temps. At a 50 degree startup temp, there's a lot of difference between the viscosity of a 5w oil and a 10w oil.

The 5w (not to mention the newer 0w) oils provide quicker lube to your bearings and especially to your cam without any fall-off at operating temps compared to 10w oils.

While a 10w-30 oil sure won't lead to any quick problems, you're better off with a lower "first" number.

Also, as previously pointed out, good synthetic oils don't use any VI improver so they don't shear down like older multi-vis dino oils.

HWY HNTR

Dont mean to hikack but it seems like some of you know what youre talking about so what oil would you use in a TT Z06??? Thanks in advance.

427435

You won't go wrong by using the factory fill.

Ikester

thats why I stick with Amsoil, everything is stamped properly on their bottles so I can sleep better at night

427435

Do the Amsoil bottles say "Meets" the specs or "Recommended" for the specs-----big difference.