Mobil 1 5W30 meets GM spec 4718M but Mobil 1 10W30 DOES NOT. WHAT GIVES?

[bighank]

Was buying gallons of Mobil 1 5W30 at Wally World at $21.95 for a 5 quart container. Also have a newly acquired 1999 Cadillac DeVille which takes 10W30 when the sustained temperature is over 50 degrees F.

Looked at both containers.

Mobil 1 5W30 says it meets GM spec 4718M.
Mobil 2 10W30 DOES NOT

Cadillac recommends the heavier viscosity oil in the Northstar engine.
Why doesn't the Mobil 1 10W30 meet the same specs as their 5W30.? BIGHANK

[submariner409]

Cadillac does not specifically recommend 10W-30 (the heavier oil) in all Northstars.

Your engine might be spec'd for 10W-30 above 50 degrees, but 2000 and later are spec'd for 5W-30, same temperature.

Like ILSAC specs, GM specs vary with the seasons or barometric pressure .

........And, in 2000, one running change was from "flat tappet" style cam followers to rollers, allowing lighter cold oil viscosities as well as accomodating the slightly reduced zinc/phosphate load in newer oils.

[N0DIH]

My mom and dad used to run Amsoil 0W30 in their N* (97 Deville) and after long trips the next day it would rattle like the engine had no oil in it. After 3-4 towings to the dealer (under warranty) GM's answer was changing the oil.... No definitive answer.

So I told my dad to run Amsoil 10W30 in. Never and issue since.

[Zorb750]

There are no 5 quart containers. One gallon is four quarts. $21 Mobil1 bottles have four quarts.

I've had decent luck with Mobil1 0w40, no rattle or valvetrain noise. No tappet or cam wear either, I've seen them closely.

[clarkz71]

Originally Posted by Zorb750

There are no 5 quart containers. One gallon is four quarts. $21 Mobil1 bottles have four quarts.
.

I'm afraid that's incorrect. Most oil's come in 5 qt containers. The diesel
oil's do come in 4 qt though like Rotella, which I now use.

[N0DIH]

I second that, I buy exactly that bottle for my 94 FWB.... 10W30 EP.... That or Rotella T 5W40 for the extra ZDDP it has....(1400 ppm in the CI-4-Plus formula)

[Zorb750]

Why do I have two four quart/1 US Gallon containers from Mobil1 in my garage?

[clarkz71]

Pictures don't lie, you can see the picture can't you, it say's " 4.73 liters/5 US quarts".
You said "it doesn't come in 5 qt containers".

[N0DIH]

They market 4 and 5 quart, depending on the grade/type. Go take a trip to Walmart and look. They carry both. Maybe it is a larger store thing. The 4 quart ones aren't a good buy, the 5 quart typically are much better. As with a 4 you have to buy one individual and that is pretty expensive in comparison to the 4 or 5 quart price.