Would mixing 3 quarts of 10w30 and 3 quarts of 20w-50 yield 15w40??
Rocky
Rocky
Mixing Oil Viscosity
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It would almost definitely end up being a 40 at 100C, but the W-number is not possible to predict. It may be a 15W or 20W. The blend would have to be tested to get the low-temperature viscosity rating. I have blended Valvoline VR1 10w30 and 20w50 before, and it has worked OK, but I never tried a true sub-zero cold start on it. If you want to get a high-zinc 40-weight oil to run in your classic cars in warm weather, it would be OK.
I don't know. I mixed one quart of Mobil 1 0W40 with 3 quarts of TGMO 0W-20 and I call it a 0W-25, but that's more a function of my bad sense of humor rather than knowledge of motor oils.
Somewhere in that ball park. Might be closer with 3.5 to 4 qts 10w30 to 2.5 or 2 qts 20w50 though. Either way, don't run it in winter.
http://widman.biz/English/Calculators/Mixtures.html
You can use the calculator in the above link to calculate the viscosity of oil mixtures if you know the starting viscosities of the oils you're going to mix.
You can use the calculator in the above link to calculate the viscosity of oil mixtures if you know the starting viscosities of the oils you're going to mix.
Originally Posted By: rocks66ss
Would mixing 3 quarts of 10w30 and 3 quarts of 20w-50 yield 15w40??Rocky
First welcome to BITOG!
Yes it would give you a heavy antiquated 40wt oil.
Motor oil is cheap in North America. Unless you've got a serious oil burner on it's last legs there are more appropriate modern 0W/5w30/40 grade oils from which to choose.
Would mixing 3 quarts of 10w30 and 3 quarts of 20w-50 yield 15w40??Rocky
First welcome to BITOG!
Yes it would give you a heavy antiquated 40wt oil.
Motor oil is cheap in North America. Unless you've got a serious oil burner on it's last legs there are more appropriate modern 0W/5w30/40 grade oils from which to choose.
I only put about 1200 miles a year on my 66 Chevelle SS with a 396, I run Valvoline VR1 and I have been running 20-50. I was thinking with cooler weather coming on, and I had 3 quarts of 10-30 left on the shelf.
Without giving it much thought, I figured the 3 and 3 mix would give me 15-40. Do I need to change oil? with all of one flavor.
There had been so much talk about ZDDP in oil I started using the VR1. I belong to a site called Chevelles.com and there is someone who goes by 540Rat that has done very extensive testing, and i guess we are finding out that high ZDDP isn't necessarily the ticket.
I've ran Pennzoil 10w40 for years until this ZDDP scare has come along, and a year and half ago there was an internet sale at Auto Zone and I bought about 50 qt's of VR1 in 20-50 for about $2.50 a qt.
I ultamatly would like to find a oil in the 10-40 range that I will feel comfortable will protect my flat tappet cam. any opinions/advise.
And thank you for the welcome.
Rocky
Without giving it much thought, I figured the 3 and 3 mix would give me 15-40. Do I need to change oil? with all of one flavor.
There had been so much talk about ZDDP in oil I started using the VR1. I belong to a site called Chevelles.com and there is someone who goes by 540Rat that has done very extensive testing, and i guess we are finding out that high ZDDP isn't necessarily the ticket.
I've ran Pennzoil 10w40 for years until this ZDDP scare has come along, and a year and half ago there was an internet sale at Auto Zone and I bought about 50 qt's of VR1 in 20-50 for about $2.50 a qt.
I ultamatly would like to find a oil in the 10-40 range that I will feel comfortable will protect my flat tappet cam. any opinions/advise.
And thank you for the welcome.
Rocky
I think your plan for mixing 10w30 and 20w50 VR1 is OK for getting a high-zddp oil with reasonable cost and effort. Since you're only driving it 1200 miles a year, cold startability doesn't seem like a major consideration for your application. What viscosity did GM originally specify for the 396? Maybe 10w30 VR1 would do the job just as well.
What viscosity did GM originally specify for the 396? Maybe 10w30 VR1 would do the job just as well.[/quote said:
A few years ago I use to run Chevron Supreme in my 97 F150. I would mix 4qts of CS with 2qts of SuperTech Full Synthetic. I don't know how well it made the internals run better but it sure helped me sleep better at night.
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