I’ll be doing this for two oil changes. It’ll be 2.5 qrts of 0W20 and a full jug of 5W30. The plan is to go all 5W30 or possibly 0W30. Trying to use up what I have. Any issues doing this? This will be going in the tundra. Thanks.
Mixing Mobil 1 Extended Performance 0W20 and 5W30
- Thread starter ARB1977
- Start date
I've done it in my cars that recommend 0W-20. I haven't had any discernable issues.
Why not just dump the whole jug of 0W-20 in and top off with the 5W-30 for one oil change and be done?
Why not just dump the whole jug of 0W-20 in and top off with the 5W-30 for one oil change and be done?
Yeah I could do that too, lol. This August we’ll be heading to Utah from Texas. I was planning to go a thicker oil for the trip.
It's totaled.
dnewton3
Staff member
OP - Let me offer a bit of tough love.
You've been here for 20+ years, and you still have to ask if mixing viscosities is OK ? ... As if thedozens hundreds thousands of threads with this same topic weren't able to convince you one way or another?
You'd be better served to worry about the 3.4L bearing/crank issues inherent in that engine series more than the oil choice. No lube viscosity is going to assuage the concerns in that regard.
You've been here for 20+ years, and you still have to ask if mixing viscosities is OK ? ... As if the
You'd be better served to worry about the 3.4L bearing/crank issues inherent in that engine series more than the oil choice. No lube viscosity is going to assuage the concerns in that regard.
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I have in waiting 0w-20/5w-20 and a greater quantity of 5w-30 Mobil Extended. This will be used in a newer Pentastar 3.6 which recommends 0w-20. Being not a believer in 0w-20, I'll be doing a blend of 3 1/2 Qts of 5w-30 and 1 1/2 Qts of the other weight. Now the question in my mind, which oil would it be a better choice to use in the blend? What I've deducted from other posts, is that the 0w-20 is the better oil since it uses more PAO to achieve the 0w rating? (In the future when I run out of what I have, it would be good to know which I should buy when doing this blend w/the majority of 5w-30 oil?) So far doing this blend ratio w/PUP, the engine runs superb. (I do short OC intervals because the drive to work is just a couple of miles and thanks to this website, I have quite a "stash" which needs to used up so I can buy some more oil in the future 
Thanks.....
Thanks.....
CleanSump
Site Donor 2026
This is a concern that should be taken seriously. Sure, there’s always a warranty and the recall, but the timing of an engine failure can create a logistics nightmare for the owner.
A friend of mine sent this picture to me last week. To make matters worse, it seems that these people were from New York. (Front license plate)
Imagine losing your engine so far from home.
There’s no tough love. I’m fully aware on the 3.4L.
Yeah it’s a gamble. Other manufacturers have their issues too. Engine failures on this engine are 1%. So far my original is running great. MPG’s are 20-25. I’m three months short of the new recall. No metal in the oil filter housing. The oil has some transparency when changed at 5K intervals.
External filter on it correct? Consider adding a Filtermag (or 2) and then cut the filters open to examine. Hopefully it stays nice and clean but would give more area for stuff to stick to if it does have issues.
Also trying to use what I have, I am blending Mobil 1 0w-20 75% and MI 10w-40 25%.
Filter mag isn’t a bad idea. Unfortunately Toyota also services the truck at 10K…oil change. I split the difference at 5K and do it myself. At 10K I syphon out the dealer bulk and add my own. Yes it’s a waste of money but it shows that the service was done. Like an idiot I paid for the prepaid maintenance.
My son went to Walmart with his wife's Tucson for an oil change with Valvoline Restore and Protect. He asked to speak with the technician and gave them a gallon ziplock filled with oil absorb mat and said he wanted the filter back with the Filtermag attached. They had no issue with that and did as asked.
This smells like WAY overthinking things. I wouldn't do the mixing thing. Theres little benefit & potential problems with doing this.
What would be the potential problems. What I may do is use up the 0W20 and top off with the 5W30.
Potential problems include mixing two different chemistries. Additives in one oil may upset the balance of chemicals in the other oil. Oil manufacturers can make very different chemistry even between viscosities of the same exact oil brand and type. Now is this very likely? Probably not. But the potential is there. Theres little to no benefit of mixing viscosities. Valvoline told me for example that mixing 0W-20 & 5W-30 does not make a 2.5W-25. They said it does not exactly work like that. Each individual oil formulation is very balanced between additives. Some additives compete for space on engine surfaces. And the formulations very by application.
That answers that, lol. I’ll get 5W30.
Additive system within the Mobil 1 Extended Performance line should be extremely similar. The only concern is the cold temp performance -- it tends to be unpredictable when you mix grades. If cold temp performance isn't an issue you have nothing to worry about.
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