List Your Favorite Oil Mixes

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Nov 25, 2003
The Tropics of Antartica
I tell ya
Last summer I mixed a 50/50 brew of Pennzoil 5/20 and Pennzoil HD 15/40 and run it from May/03 till Nov/03 . The oil pressure was only a small bit higher when cold opposed to a 10/30 dino used previously and gas mileage was not affected compared to the straight 15/40 . Both these oils use the Shell VII so compatibility is not an issue .

Through summer when cold oil performance is not such an issue this is a good way to get 5 buck a quart lasting ability for a buck fifty in engines that can run this weight .

I think probably the Delvac 1300S and the Mobil Drive Clean + would make a good brew for summer use also but a guy would not get quite the hefty additive pack that the Pennzoil offers .

I know there is some mixers out there so join in with your brews !
I don't use a mix of oils as you are describing but for the few vehicles that I maintain I like to use 6 ounces of Schaeffer's Moly E.P. additive with each oil change. I don't add the Moly E.P. if I'm using Schaeffer's oil but with other mineral based brands I do use the additive.

I just like the peace of mind that I get from the extra additives. If it weren't for the Schaeffer's I'd use the Valvoline Max-Life additive but it's rather expensive when compared to the Schaeffer's product.
Have not found one per se;
Closest thing to it
about 3Quarts of Molybdenum Disulfide-Straight 30

about 1.25 quart of Moly Syn (old)- Straight 30

About 0.25 Qrt. of VII/cleaner about visc 2000 @ 40C cSt

with a mix of about 4 ounces of the above VII and a THINNER/cleaner added about midway between OCI's... or when the TBN drops about 1/3 - 1/4.
Before this I'd mix all kinds of brews and I liked a lot of them... most had either Moly (SYN or Natural) OR MMO.
Even though I'm not doing it now.. I think a 25% mix of the 15W-50 Mobil 1 with their 10W-30 is good. But lately we have seen some pretty good rsults with 20 weights-so maybe the heavier oils are not that necessary in many cases.
I currently use 5 quarts of M1 5W-30 and one quart of M1 10W-30. It's a F150 with the 5.4l I'm just not convinced that the 5W-30 is thick enough for this monster V8. Yeah, I know, that makes that oil combination something like a 7W or 8w, but it's a little thicker non the less. Plus, M1's are little on the thin side.
among other concoctions, i'm thinking about throwing in some m1 15w-50 not for the viscosity but for the slightly more robust additive package. 1 qt with the xw-30.

so many things to mix, so little time.

just a thought.
For my temperature range the manual for my 79 Toyota truck with the 20R engine says to use 20W/40. 20W40 was hard to find then and has pretty much disappeared altogether. I have been using Castrol GTX and recently switched to Castrol semi-synth. Both half and half mix of 10W30 and 20W50. On the surface this equates to 15W40. A weight that actually is made by Castrol in both regular and semisynth versions.. It is a little harder to find so I continue to use the mixture. The truck now has 165000 miles on it and has every bit as much power as it had when new. I recently drove a new equivalent model Toyota truck and while much tighter and quieter than my 24 year old workhorse, it really was not noticeably quicker.
I've never tried it but I wonder if a mix of Delvac 1 5w40 and M1 5w30 would be any good?

Since Delvac 1 only comes in 4L (or 4 quart) jugs, and many cars take 5 to 6 quarts, one could just buy a single jug of Delvac, and top off the rest with M1 so they don't need to mess around with trying to measure out a small amount out of a second jug of Delvac 1.
3 quarts 15W-50 Mobil and 3 quarts 10W-30 Mobil in the winter for my 4.0L Jeep motor...straight 15W-50 Mobil in the summer...plugged in (block heater) on extreme nights around likes the thicker mix
My favourite (and only) mix is 50/50 M1 0w30 and 5w30 in my RSX Type S. For Jan and Feb I'll be topping off with 0w, so before my next oil change it will probably be closer to 70/30.

I burned a lot of M1 with straight 5w30 (3.5L in 5k), so I'm adding some 0w and watching it closely now. It was my first fill with M1, so I'm cutting it some slack for another fill.
What would be the viscosity of 3.5 qts of m1 10w30 and 1 qt. of 15w50?

Also, 4 qts of 10w30 and 1 qt. of 15w50 M1.
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