Oil - What weight do you use? (Please forgive me for asking...)

[amblerman]

They seem to be allowed to do exactly that in the US due to some old ruling on marketing. In Europe it'd be sold as a semi-synthetic.

Here's the best explanation I can find for the distinction you are making between "full synthetic" and "true synthetic"

https://www.pca.org/news/2015-11-02/syn ... -motor-oil

That is a good description.
The issue is that a lot of people think "synthetic" should only be applied to oils that use group IV or V oils as their base stocks.
ie. the base stocks are created in a lab vs refined from petroleum crude oil.

if you buy synthetic oils from the major brands (Mobil, Pennzoil, Castrol, etc) then you get a "synthetic" that is a blend of possibly group III, IV, V in some percentages. The percentages are probably higher for the cheaper group III base stocks.

Because of a court ruling, the use of synthetic in labeling really means nothing.

Even a lot of "conventional" oils sold in stores actually contain some "synthetic" oil because the oil has to meet certain specifications (ie SN Plus, DEXOS 1 G2, or European standards like A1, A4, etc) and oils made with inferior Group I and II oils won't meet the newest standards.

In a previous post I mentioned June like Redline oils. Those are 100% group IV I believe.
That's also one reason they are more expensive.

-A

[redc70]

I use Mobile 1 Full synth 10W30 in my 99 C70 LPT, and it is HOT here on south Texas. 155k miles and still a champ. I have also used same weight conventional in same car. I see NO difference in anything as far as mileage, smoothness, starting up cleanliness of internals that I can see etc. I do change every 5k regardless of what I use.
Its interesting that in the other forums I belong too, (ClubArmada and Mercedes forums) that most are concerned with change intervals vice synth or dino. The SL500 and 560 SEC both get dino at the correct weight. Now, I know the MB engines are completely different animals than our beloved Volvos, but I think the only way to decide which is best for your application is stick with a weight and type for a while and send samples to be tested. Thats really the only scientific way to be sure.

[ZionXIX]

Oh God! Hurry and shutdown the thread! Before it's too late! Before bobistheoilguy posters find us....

[amblerman]

Too late. I'm on there as well..

I agree that the discussions over there can get pretty deep.

The conclusion I came to after reading a lot of stuff over there is that if you're using the correct weight oil that meets the right specs and change it in a reasonable interval, you'll be fine with respect to keeping your engine free of oil related failures. That's why I have a stash of oil meeting those requirements vs trying to hunt down and find the "ultimate" oil for my cars.


[edited to add content]

[callahanoffroad]

Oh God! Hurry and shutdown the thread! Before it's too late! Before bobistheoilguy posters find us....

^^^This. I always tell new members to never ask about oil weight or octane.

That being said I like the very exclusive SuperTech brand 10w-40 in a 5 quart jug.

I change it every ~5000 miles which is about 8-10 weeks for me.

I get about 1.5 mpg avg better gas mileage with 10w-30. But I burn less oil with the 40.

This is my $.02 contribution.

[quietlymknnoise67]

I use Mobil One 0w40 Euro Formula

[Motu]

I'm using Penrite HPR15 - 15W-60. That should upset a few.....

[JimBee]

I used to use Amsoil in my 93 854 when I first bought it in 2008 but after acquiring 2 96 855's I went to whatever "full synthetic" brand is on sale and usually in the 10-40 viscosity, although I've used 5-40. Here in Minnesota my 93 (which I drive as my winter car) starts readily on 10-30 even at -20 F. I go through a quart and a half November to May, with some highway, mostly inner city driving, but overall, probably about 5k miles.
Two of my 850's have manual trans and I still use Amsoil ATF in those transmissions. When I first got them, I drained what was in them and filled with Amsoil, ran for maybe a 1k miles, drained and filled again. Interestingly, the 93 had a slight metallic whine when decelerating in first or second gear; after flushing and filling with Amsoil it went away and hasn't recurred.

[wizechatmgr]

I've been using the Rotella T5 and T6 mostly. I have found the T5 leaks a bit less with my seals. I've also tried Amazon's "synthetic" and I don't think it is any better or worse than any oil - provided one sticks to some form of change interval that isn't excessive.

[MoVolvos]

I've been using the Rotella T5 and T6 mostly. I have found the T5 leaks a bit less with my seals. I've also tried Amazon's "synthetic" and I don't think it is any better or worse than any oil - provided one sticks to some form of change interval that isn't excessive.

Recently tried the new (to me) Mobile 1 0-40W from Costco in 3 cars. Got it out as soon as I could get to it. Did drive it a little as a flush. There is one better but you have to buy it direct or through a local Rep Min 1 case @ 24 quarts. It's also very expensive but the company provides an oil testing program.





https://www.amazon.com/Shell-Rotella-Sy ... way&sr=8-3