Blend my 10W40 or buy some 5W30?

[Shrubitup]

I have almost 100 quarts of Castrol GTX SynBlend 10W40. It has an API SN rating. It's a good oil but thick and causes MPG to decline. It gets about 25*F here for the absolute winter time low temperature so even this "molasses" works fine there.

My truck (07 Nissan Titan 77K miles) calls for 5W30. I don't use it to haul anything other than groceries and two or three dirt bikes (less than 1,000 lbs payload always). I don't tow anything ever. Costco has some Mobil 1 on sale in multiple viscosity(s) for $2.66 a quart after rebate this month.

Question: Should I buy 0W20 and blend my molasses with it or just get the 5W30?

I've done some blending before and it worked great.

 

[53' Stude]

My 2 cents: get the correct 5w30 like say MC 5w30 synblend, QSAD or which ever oil you like

 

[CT8]

"molasses"

 

[pbm]

If you mix it 50/50 with 0w20 you'd have something close to 5w30 which should be fine for Seattle's temperate climate...you could do 60/40 or even 70/30 in the warmer weather.
I'd stick with Castrol so the additive package is similar...

 

[Torrid]

I'd just run the 10w40 you already have.

 

[Nick1994]

Originally Posted By: Torrid
I'd just run the 10w40 you already have.
Yup.

It's probably just a coincidence that the mpg went down, I highly doubt it was due to the oil

 

[Shrubitup]

Originally Posted By: car51
My 2 cents: get the correct 5w30 like say MC 5w30 synblend, QSAD or which ever oil you like


That'll work. The other use for the 10W40 is in my four stroke dirt bikes which works great and roughly $9 cheaper than "motorcycle" oil.

 

[Shrubitup]

Originally Posted By: Nick1994
Originally Posted By: Torrid
I'd just run the 10w40 you already have.
Yup.

It's probably just a coincidence that the mpg went down, I highly doubt it was due to the oil


Maybe since my wife primarily drives the Civic the MPG went to 25 combined (very little hwy). When I only drive it and using 5W20 it gets 27MPG. I put in the 10W40 and it went to 25 but she is a lead foot.

 

[Merkava_4]

Use a viscosity calculator if you're gonna blend it. Don't just guess at it.

http://www.widman.biz/English/Calculators/Mixtures.html

 

[MrQuackers]

I changed my oil (SL2) with 1 quart of VMLHM 10w-40, 2.5 quarts of VMLHM 10w-30, a 16.9 ounce bottle of Bar's Leaks RMS Repair and half a can of LiquiMoly LM2009.

Factory spec is api SG 5w-30. Two highway trips averaging 40 mpg for over 250 miles and another of over 400 miles, 39 mpg which included significant stop and go traffic in the mix.

EPA estimate for this vehicle is 21/30

 

[69GTX]

That 100 qts could last well beyond the lifetime of that truck. If you mix it that only doubles the amount to use up. I'd be looking for people to trade/barter with so you can start using the specified 5w-30 oil. If that truck were working hard every day then the 10w-40 might actually work well.

 

[Torrid]

Or sell it super cheap to me. I have no qualms with running 10w40 in the Jag.

 

[Shrubitup]

Originally Posted By: Torrid
Or sell it super cheap to me. I have no qualms with running 10w40 in the Jag.


I have no issue with the viscosity besides gas mileage or at least the perception of gas mileage but I've used Delo 15W40 before and also had a hit in MPG.

 

[KCJeep]

I'd just use it as it is, or at most add a quart of inexpensive 5w20 per OCI. A jug of Magnatec 5w20 would only set you back about 18-19 bucks and would get you a thinned out syn blend for 5 OCI's.

Remember, even if the oil is a smokin' deal, it's only really a deal if you can actually use it. Been burned on that one myself so I have learned not to pull the trigger quite so easy.

 

[SilverC6]

You've over bought the 10W-40.

I worry about doing that myself sometimes when I bump into the deal of a lifetime at AZ or other retailer.

No doubt your fuel economy would suffer slightly compared to a fuel saving 5W-30. But probably not over a few gallons of gas per OCI.

Still, that might be enough of a savings to offset the cost of the correct 5w-30.

 

[Shrubitup]

Originally Posted By: SilverC6
You've over bought the 10W-40.

I worry about doing that myself sometimes when I bump into the deal of a lifetime at AZ or other retailer.

No doubt your fuel economy would suffer slightly compared to a fuel saving 5W-30. But probably not over a few gallons of gas per OCI.

Still, that might be enough of a savings to offset the cost of the correct 5w-30.



That answers that. I ran the math and at $2.66 per quart I could buy 29 quarts with the money saved in my Titan (31 extra gallons of fuel consumed at $2.50 a gallon using the thicker oil). In the Civic example I could buy 20 quarts with the money saved.

I'll get a stash of 5W30 going and use the 10W40 in my dirt bikes.

 

[Shrubitup]

Originally Posted By: Torrid
Or sell it super cheap to me. I have no qualms with running 10w40 in the Jag.


$1 per quart sound good?

 

[Shrubitup]

Update: recent inventory reports 55 quarts available so I've used some.

 

[FutureDoc]

I would run it. No issue with the 10w40 in that engine.

I run 10w40 T5 and/or cut it with QS Defy 5w20 in my 5w30 recommended Subaru... but then again, 10w30 and 10w40 are also acceptable. Temps around here get about 0F as a low.

 

[Shrubitup]

Originally Posted By: FutureDoc
I would run it. No issue with the 10w40 in that engine.

I run 10w40 T5 and/or cut it with QS Defy 5w20 in my 5w30 recommended Subaru... but then again, 10w30 and 10w40 are also acceptable. Temps around here get about 0F as a low.


Ya I have 48 quarts of 5w20 valvoline that I purchased for $2 each. I'll just blend with that to get 7.5W-30.

When my stash depletes I'll look for M1 on sale and with a $12 rebate and run it for 10K miles or double my suggested OCI which will make it $1.33 a quart. I'm learning, lol.