Mixing 5w30 w 10w40 4:1 to reduce stash???

[FlyNavyP3]

Hey BITOG gurus,

Quick thought for you guys. I have a stash of some Valvoline 10w40 motorcycle oil that I bought about 4-5 years ago that I'm still trying to use up. I have about 12 quarts left. I was running it in my 1987 4Runner with the 22RE engine with great success with the exception of a very noticeable decrease in fuel economy when running a 40wt vs a 30wt oil. I can show that without a doubt using heavier oil (40 vs 30) costs me about 2 MPG across the board (city, mixed, highway) in fuel economy. On Xw30 it gets 17.8 city and 20-21 Highway, switch it out to Xw40 like it has in it right now and it drops to 15-16.2 city and 17.8-18.2 highway. It's repeatable data spread over 5 years and about 60,000 miles across all seasons that immediately shows improvement back to the higher MPG as soon as it's filled with 30wt again.

Ok so... Maybe not such a quick thought, but I say all that to say this...

I was planning on taking advantage of the Napa Synthetic sale this month, planning on buying probably two cases of 5w30 for use in the 4Runner and in my 2004 Lexus ES330. Both vehicles hold 5 quarts, I was considering running 4 quarts of the Napa Syn 5w30 with 1 quart of the Valvoline MC 10w40. That would give me enough oil to do 6 oil changes and would use up half of my stash of my 10w40 MC. The other 6 quarts I can use in my 1976 Chevy truck with a 350 that's a bit tired and prefers a heavier oil (and frankly will never get good mileage).

What are your thoughts? Is this a recipe for disaster or a viable plan? Both vehicles are driven in Florida where save for a handful of days per year the temp is never below 40 and evenin the cold months the temps are in toe 50-60's with summer temps in the 85-95 range.

Looking forward to your thoughts!

 

[JC1]

Sounds reasonable.

 

[JamesBond]

2 mpg going from Xw30 to Xw40? When will the government do something about these gas guzzling oils?

I'm not against mixing oils but I would just use the 10w-40 in the truck and the 4 runner for the next oil change, then it'll be gone. Why bother dragging it out for next couple of years.

Both will be fine with 10w40 in Florida.

 

[gfh77665]

Due to buying out over 200 quarts for $1 each a few years ago, I have done this very thing many times.

Four 5w30 PYB + 1 SAE 30wt.
Three 5w-20 Mobil 5000 + 2 10w-40's
Four 5w-20 PYB + 1 40wt.
And so on.

It worked real well because about 160 (80%) of the quarts were 5w-20, 5w30, or 10w30, and only 40 or so were 10w40's or straight 30's or 40's. I took about 15 of the heavier straight weights out for lawnmower use, and the 25-30 leftover quarts blended excellently with the thinner multigrades. I did avoid mixing brands, just as a precaution.

Years have passed with ZERO issues. In warm FL, you can mix grades with abandon!

 

[FlyNavyP3]

Originally Posted By: JamesBond
2 mpg going from Xw30 to Xw40? When will the government do something about these gas guzzling oils?

I'm not against mixing oils but I would just use the 10w-40 in the truck and the 4 runner for the next oil change, then it'll be gone. Why bother dragging it out for next couple of years.

Both will be fine with 10w40 in Florida.


The 4Runner currently has 10w40 in it, although I sense doubt in your reply as to the significant change in fuel economy I can assure you it's true. Over the course of the 10,000 miles it would take me to consume that case of oil in the 4Runner would represent a significant cost in fuel at 2mpg. At a difference in my daily use of 2 MPG on 40wt vs 30wt over 10,000 that represents a savings of $139 at the current price of $2/gal. At the rate I put miles on the 4Runner and Lexus if I spread it between the two or used it solely in the 4Runner it'd be gone in about a year either way. The Chevy likely won't need an oil change in the next year due to its limited use.

I appreciate the input!

 

[FlyNavyP3]

What are your thoughts with mixing 3:2 5w20 and 10w40 to be closer to the spec of 5w30? Or should I just stick with 5w30 as the majority oil?

Nice to hear I'm not the only one who mixed or considered it.

 

[Run]

I would save all 10w-40 for the 76 chevy. The old engine will enjoy it. Keep the modern cars on the 30 weight.

 

[CT8]

I would run the 40 in the Chevrolet it is a match.

 

[Shannow]

Use the 10W40 all at once, and in the Chevy.

If the 4Runner really IS that sensitive to viscosity, then you'll probably burn the same amount of fuel over multiple oil changes with your mix, just less per OCI.

 

[umungus1122]

Originally Posted By: FlyNavyP3
What are your thoughts with mixing 3:2 5w20 and 10w40 to be closer to the spec of 5w30? Or should I just stick with 5w30 as the majority oil?

Nice to hear I'm not the only one who mixed or considered it.

I'd go this route. 2mpg sounds like a lot, especially in the summer.

 

[BrocLuno]

If anyone believes (or knows for certain) that there will be a MPG hit of more than 0.1mpg for an oil type/grade/weight, it would be cheaper to give the oil away than run it.

PM me and I can send you my address

There is something else going on with that mileage hit? It could be related to cam timing if equipped with VVT, or something like that. But it is not related to viscous drag ...

 

[FlyNavyP3]

Originally Posted By: BrocLuno
If anyone believes (or knows for certain) that there will be a MPG hit of more than 0.1mpg for an oil type/grade/weight, it would be cheaper to give the oil away than run it.

PM me and I can send you my address

There is something else going on with that mileage hit? It could be related to cam timing if equipped with VVT, or something like that. But it is not related to viscous drag ...


The 4Runner has no VVT, it's pretty simple as far as engine technology goes. I don't think it's viscous drag causing the reduction in fuel economy. If anything I think it's due to pumping loss in the oil pump, the engine I suspect still has very tight bearing clearances as the oil pressure is quite high, due to the high numerically rear axle ratio and relatively short overdrive and tires it spins quite a few rpm at any road speed, even with the oil fully warmed up it's on the oil pressure relief of 78-80 psi by 2400-2500 rpm and stays there at about 80-87 psi depending on engine rpm above the relief set point. At 75 MPH it's turning 3350 rpm with about 85 psi at 80 it's a touch higher. Pressure is the exact same at speed with 30wt oil but I suspect that the pumping loss is the difference in mileage as I can't attribute it to anything else rationally. Time and time again if I change oil and go back to a 30wt the very next fill up the mileage goes back up approx 2 mpg and stays there so long as it has 30wt in it. Switch back to a 40wt on the next OCI mileage drops and stays lower, seems unaffected by season but Florida stays pretty moderate year round. Over 60,000 miles of various OCI's the pattern repeats over and over again. Pumping loss is all I can legitimately attribute it to and this is by far the most sensitive vehicle I've ever had in regards to oil viscosity and mileage associated with it.

As for those recommending I use the oil in the Chevy I can do that, but I still have about 10 gallons of HDEO 15w40 in various brands to run in it and considering I only put about 1500 miles per year on the truck it will likely last me the next 20 years. That's why I'm trying to find a way to use up the 10w40 in the vehicles I put considerably more miles on.

Perhaps I will just try it in the Lexus and see if it suffers the same mileage drop as the 4Runner, it does have VVT though so I'm a bit leery trying a full fill of 40wt in a car that specified 5w30.

I appreciate all the opinions I will weigh them all in making my decision.

 

[SR5]

Both Napa synthetic and Valvoline MC oil are made by Ashland and have similar add packs from the VOA & UOA I have seen. Sodium detergent. I think they should play well together.

The Valvoline 10W-40 MC oil, I assume is a heavy mineral oil with high zinc (ZDDP) and shear stable VII polymers.

The Napa 5w30 synthetic, is a light GF-5 30 wt oil with a regular resource conserving add pack.

Mix them together for a heavy 30wt semi-synthetic with extra zinc. Like a beefed up DuraBlend 10W30, sounds nice to me.

I was once thinking of going out and buying a light GF-5 SynPower 5W30 and a heavy VR-1 10W40 and mixing them together myself, for just that effect. Also both Valvoline / Ashland product. In the end I just purchased the Oz Castrol Magnatec 10W30, as it was a heavy A3/B4 semi-synthetic. Much the same result and it's already mixed up for me by Castrol and ready to go.

I like your plan, give it a go, then bump this thread and report back with the results.

 

[Rolla07]

Sell the 10w40 oil...

 

[BrocLuno]

I'd sell the HDEO and the 10W-40 to inboard boat owners. You got warm water down there. So a lot of fishermen will be running heavier oil. Mercruisers like a bit heavier oil as they age

I also agree with SR5's mixology. You have lots of oil and you just need to work out what goes where. I suspect the Lexus will maybe not be as sensitive... But the only way to know is to try

Maybe start getting some 5W-20 on sale and mix away following some good add-pak logic ...

 

[FlyNavyP3]

Originally Posted By: SR5
Both Napa synthetic and Valvoline MC oil are made by Ashland and have similar add packs from the VOA & UOA I have seen. Sodium detergent. I think they should play well together.

The Valvoline 10W-40 MC oil, I assume is a heavy mineral oil with high zinc (ZDDP) and shear stable VII polymers.

The Napa 5w30 synthetic, is a light GF-5 30 wt oil with a regular resource conserving add pack.

Mix them together for a heavy 30wt semi-synthetic with extra zinc. Like a beefed up DuraBlend 10W30, sounds nice to me.

I was once thinking of going out and buying a light GF-5 SynPower 5W30 and a heavy VR-1 10W40 and mixing them together myself, for just that effect. Also both Valvoline / Ashland product. In the end I just purchased the Oz Castrol Magnatec 10W30, as it was a heavy A3/B4 semi-synthetic. Much the same result and it's already mixed up for me by Castrol and ready to go.

I like your plan, give it a go, then bump this thread and report back with the results.


I think I will experiment with a few different blends using the NAPA Syn (blended by ashland) and report back, in my next post I will include a couple UOA that were done using the Valvoline MC 10w40 and one with Valvoline Durablend 10w40. See another thread I'm building over in UOA section for all 5 years and ~60,000 miles of UOA using my stash of 15-27 cent per quart oils (with a few exceptions here and there).

I think my plan right now is to try a run with 3:2 0w20 or 5w20 Napa Syn and 10w40 MC, another with 4:1 5w30 and 10w40 MC in the 4Runner. I may also get brave and try the 3:2 0w20 and 10w40 in the Lexus pending the UOA results in the 4Runner. I will definitely bump this thread with those results and link the UOA thread.

 

[FlyNavyP3]

UOA w/10w40 MC this oil sat for 8 months while I was deployed, it had about 400 miles prior to me leaving on deployment, then got the remainder of the OCI after I returned, filter was a CarQuest Blue 85515 (Ph-8A size)



OCI after my return from deployment, all in town driving this time OCI limited to 3,000 to watch for copper; same filter as previous OCI.



Valvoline DuraBlend 10w40 for comparison sake. Filter unknown.



Valvoline NextGen 10w30 thrown in just for fun, filter was MANN ML1003.

 

[pdxglocker9mm]

I would go with a synthetic 5w20
It would when mixed with the 10w40
Pull your average down closer to what is the reccomemded spec.
Did this with some 5w50 and 0w20 and some 5w30
Ended up with a witches brew of 2.5w30 worked fine
Engine didnt notice a difference
No milage change
No noise
No consumption

 

[FlyNavyP3]

In terms of viscosity at 100C what would the difference be in conducting my "blend" with 5w20 vs 0w20 mixed 3:2 with the Valvoline 10w40 MC oil? Is there any way to determine the final viscosity when blending oils in this manner? Other than using a percentage based formula?

 

[fdcg27]

Yes, you can use a viscosity calculator formula, which seem to work pretty well at the higher end of the temperature range while not as well at really cold temps.
Google Widman viscosity calculator bobistheoilguy and you should find a thread with a link.