Mixing Oil Weights?

Hey folks, tried searching to no avail.

I'm in the middle of doing an oil change on my '21 SR5 and realized that I'd only bought 6 qts of 0W-20 oil. I'm also planning on changing the oil in my Tacoma today and it takes 5.5 qts of 5W-30.

Instead of heading out for that last 0.5 qts of 0W-20 for the 4R, do you think I could add the leftover half quart of 5W-30 from the Tacoma's oil change and call it good?

I'm asking because, if this is okay, it would save me from having to throw away a half quart of 0W-20 AND half a quart of 5W-30 every time I changed oils. Both oils are full synthetic Pennz. Platinum.

Thanks!

 

I would. The manual recommends 5w/30 for some circumstances, so it shouldn't hurt anything.

 

Thanks, I was kind of thinking it wouldn't be a big deal with only half a quart, especially with summer coming up.

 

Why would you throw it away, though? Leave the half quart in your garage for the next oil change...

 

Good point. For awhile I was just buying the 5 quart jugs and saving the remainder for the next change.

 

I don't like using oil that has been unsealed and sitting in a non-temperature-controlled environment for 6+ months. I know, it logically doesn't make sense.

 

Your engine is a non-sealed, non-temperature controlled environment.

 

I know, that's why I'm changing the oil

Edit: My oil changes are typically based on length of time since last oil change rather than mileage.

 

That's sig material.

 

Won’t make a difference.

 

I'm guessing you guys forgot that there are recommended timespan limits between oil changes? For many vehicles, like the 2TR-FE in my Taco, it's 5,000 miles OR 6 months (i.e. regardless of mileage, including zero). For the 4R, it's 10,000 miles, or once per year. If Toyota doesn't recommend letting oil sit in an engine unused over a certain period of time, why would it be any better in an unsealed bottle?

 

Ever think of just putting the same weight oil in both engines? 5W 20 or 5W 30 and just stay with it. You are not dealing with temp extremes like northern climates so cold weather start ups are not an issue and full synthetic oils don’t turn to paste like conventional oils at -40 degrees. It would save you a lot of headaches. There a quite a number of oil viscosity studies available to check out on you tube that should help you with an informed decision.

 

I have thought about it, and would love to, but right now the 4R is still under warranty and I want to make sure records show that the recommended viscosity was used.

Just some background, my 2006 Taco 4x4 with the 2TR-FE 4 cylinder calls for 6.1 qts of 5W-30 per oil change in the owners manual. But 3 years later the same engine model was recommended 0W-20 (and has ever since, with only dual VVT being the most obvious change in 2016). Same goes for the 1GR...the OM originally recommended 5W-30 in the Tacoma and FJ, but now requires 0W-20 since like 2009 or so. Were any changes/improvements over the years reliant on the thinner viscosity, or is it only recommended for fuel economy purposes? I guess that was my original concern when starting this thread.

 

The 0W 20 water like oil was developed and recommended so fuel mileage standards could be met. I used to run 20W 50 in my 454 race car because that is what was done back in the day.... verify with your service department, but 5W 20 or 30 won’t affect your warranty coverage. It is listed in your owners manual as an alternative. The combustion process in an operating engine creates contamination in the engine oil that is acidic. This is why you do not store a car without changing the oil first. Unused oil in the original container won’t go bad. Enjoy your trucks and change oil as you see fit. We are only trying to provide you with info, but ultimately it’s your decision. No hard feelings.

 

You cant mix viscosities. The two weights will lead to oil curdling. That’s why your engine blew. Vvti system will have to be dismantled, and the curdles will have to be blown out with an air hose.

edit: fyi, Im joking. Re-read my post and it sounds like Im being serious lol

 

STP Oil Treatment prevents curdling of mixed oils of different viscosities. C’mon, everyone knows that. Not so well known is that you can substitute a couple of tablespoons of Marvel Mystery Oil and achieve the same thing.

Seriously, I wouldn’t be afraid to mix oil in a pinch but I wouldn’t make it a habit. And I wouldn’t try to standardize on one oil for two vehicles with different recommended viscosities. Just put in what they tell you to.