*sigh* another oil Question

[PanzerSD]

I've used Synthetic oil in my Diesel before, and it's great, but is it really neccessary in a gasoline engine? or will regular 10-40 do just as good a job?
check sig for vehicle in question

[Chas H]

I use 5w30 dino oil in my gassers. Up there in the great white north 10-40 is way to thick.

[PanzerSD]

Oops, mis typed 10-40 I did mean to say 10W30. should 5W30 in winter be reaonable? I know it would help with cold weather starting, but once that oil heats up is it going to be adequate to keep the lubrication..

[Chas H]

Originally Posted by PanzerSD

Oops, mis typed 10-40 I did mean to say 10W30. should 5W30 in winter be reaonable? I know it would help with cold weather starting, but once that oil heats up is it going to be adequate to keep the lubrication..

I use 5w30 all year down here in PA. If I lived in a colder climate I might consider a 0w20 for winter-that weight is only available in synthetic.

[pawoSD]

I use the same synthetic in my gasser that I use in my diesel. Rotella 5w40....it seems to like it. I've driven it 6k on the stuff so far....and it runs great.

[Chris A]

Dyno oil breaks down over time. if you change it every 5,000 miles your motor will not know the difference. Synthetic is better but just keeping the oil changed should be good enough unless you are driveing like a mad man....

[pawoSD]

Originally Posted by Chris A

unless you are driving like a mad man....

I do!

I am overly anal about it....I do synthetic every 4k on both diesel and gasser.....still only works out to about 2 changes a year per car (or less)....pretty minimal

[dhjenkins]

Be advised, according to the API (American Petroleum Institute), if an oil contains ANY synthetic oil it can be labeled and sold as a "full synthetic".

A full synthetic is made entirely of group IV base stocks, as opposed to a mix of II, III & IV.

If you want the best oil, forget the laughable API starburst and/or the ILSAC designations. An ACEA A2/B2 (or above) is an excellent choice for most vehicles unless your engine specifically requires a different designation.

You also need to read the label very carefully. For example, "Meets or exceeds GM4718 for engine protection" actually means it failed to meet the GM4718 specification. Engine protection is only 1 criterion on which the GM4718 spec is tested on, so unless it states on the bottle "Meets or exceeds GM4718", it failed. (I'm using the GM4718 spec because it's the only one I can remember off hand).

Also, all oils are not created equal. Believe it or not, some 5W30's are actually thicker than 10W30's at operating temperature; and if you're using bulk oil, forget it. Drum oil is notoriously cheap and low quality, passing their lubrication tests by the use of additives which break down quickly once used in an engine.

I could drone on and on about this, or you could go to motor age magazine online and search for some articles by Kevin McCartney, a noted tribologist.

Unfortunately, most of the info I have on oil properties/qualities comes from an industry site, iATN.net, which doesn't allow sharing of content.

It's also important to note that oil isn't just oil. Typical dyno oil is about 75% oil and 25% additives, which do wear out. Once those go, the actual protection properties of your oil plummet.

If you really want to know what's going on inside your engine (and how often you need to change your quality oil), check out blackstone-labs.com. You might find that with the correct oil you can go from changing once every 5k miles to double or even triple that, according to your engine health and driving habits.

[lkchris]

It's all so futile to discuss this.

Just look up your car in the following fluid specification document from Mercedes and make sure you're using an oil that qualifies. If the qualification is not printed on the bottle, it doesn't exist.

http://www.startekinfo.com/StarTek/outside/9511/?requestedDocId=9511

[babymog]

To the OP:

No, synthetic is not necessary in your (sig-line) gas engine. It also is not necessary in your diesel unless specifically required as in some late-models.

If you prefer it in your diesel however, as it has the same advantages in the gas engine, I'd expect that you'd prefer it in the gasoline engine also.