Speaking of motor oil......

[JohnnyG]

Ooooh No, another oil topic........

Has anyone noticed the new "GREENER" Mobil 1 0w-30 full synthetic motor oil? Saves fuel, is GM4718M (pumpability) and GM6094M rated. Covers the temperature range from at least 0°F to 100°F, and is recommended anywhere that a 5W-30 OR 10W-30 is called for?

I was considering using 0W-20 in the new Caddy, which is used in my 5.7 Hemi Dodge truck, but I think this will be my choice from here on out. Full synthetic, and sounds like one heck of a base oil containing minimal viscosity index improver additives.

[Cadillac Jim]

I looked into it once and I believe that the 0W-30 oil is best for extremely cold climates, where the car is started at temperatures below 0 F on a regular basis, at least part of the year. At warmer temperatures, it's very much like your 5W-30 or 10W-30.

Is there any reason to believe that it offers better engine performance than 5W-30? I can feel the difference between 5W-30 and 10W-30, and by comparison the engine is just plain sluggish with dino oil of either grade.

[joeb]

you can feel a difference between 5-30 and 10-30? performance wise or what? what do you use in the summer? 10-30 syn oil or ? how about winter? weight and syn or dino?

[Ranger]

I know I am a dinosaur, but that scares me. I still use 10W30.

[KHE]

I use the grade of oil that is recommended by the manufacturer - experimenting could lead to some very costly repairs.

[Bruce Nunnally]

Concur with KHE; I loved the engineering input on this topic -- why would you NOT use the oil grade we designed the engine for, and tested the engine for?

[Ranger]

Why? Because I remember once discussing this with the Guru. I don't want to put words in his mouth, but he said 10W30 was fine to continue to use. Reading between the lines and by what he DID say, lead me to believe that GM went to 5W30 to satisfy CAFE and if left to their own choices, they'd have stayed with 10W30, and so I did. He did admit that the difference in mileage would be negligible and would take instrumentation to see.

[KHE]

Why? Because I remember once discussing this with the Guru. I don't want to put words in his mouth, but he said 10W30 was fine to continue to use. Reading between the lines and by what he DID say, lead me to believe that GM went to 5W30 to satisfy CAFE and if left to their own choices, they'd have stayed with 10W30, and so I did. He did admit that the difference in mileage would be negligible and would take instrumentation to see.

Agreed - When I responded, I was referring those goofy 0W-XX grade oils.

[Cadillac Jim]

In my own daily driver, I can tell the difference between my favorite, 5W-30 Mobil 1, and 10W-30 Mobil 1, and dino oil of any weight. Throttle response at low RPM is the key; I can tell right after I start a warm engine when the car is driven out from the dealer work area for delivery. The engine just has a tad more snap. I have no real idea why. The effect was a lot more noticeable in my previous car, a Quad 4 HO.

My dealer started recommending 5W-30 year-round for Mobil 1 customers in the 2001 time frame. I feel quite secure in keeping on using it, since I have been using it since 1997, and the original engine was just fine and clean as a whistle inside at 116,500 miles when a head bolt pulled.

[JohnnyG]

Well this is a discussion group, and you all bring up some fine points. After researching the 0W-30, and the new "green" labeling that Mobil1 decided to use, I found that the oil is exactly the same as their "Silver Cap" 0W-30. No surprise here, just marketing again at its finest!

But (and I've heard all the "why did you buy a Caddy if you had to worry about fuel economy" comments before) for those that would like to get top fuel economy, I think it is a legitimate and HARMLESS choice. In other words, over the life of the engine, it will do no harm, nor will it shorten that life in any way.

So, if you can save a couple of gallons of fuel, and get an HONEST 28 MPG on the highway, why not go for it?

For some of the older engines, and those with leaks, this may not be an option, nor would I recommend this oil to any pre-2000 flat tappet versions of the Northstar, but if you own a newer version (post 2000) rollered Northstar, calling for synthetic Mobil1 5W-30 anyway, this is a small deviation from factory fill. Yes, I can see the CAFE angle too, but I choose to be part of the effort, not a detractor.

GM can be considered a little bit behind the curve when it comes to fully embracing synthetic oils. I remember the guru saying that the only reason GM decided to use synthetics in the first place, was to avoid having to develop and fit an oil cooler under the hood of a Corvette. Now synthetics are called for almost universally for their lack of VII's (which stuck many a N* ringset) as well as their resistance to sheer and probably a few "economic" (spelled incentives) reasons. Let's face it, synthetics make a better base oil, otherwise 0W-20 wouldn't even be possible!

I'll try it, I may not like it, but I'm certain that it would at least make an excellent winter alternative to the "year round" 5W-30 Mobil1.