Mixing Oil Grades

You can use 0w20 in any vehicle that calls for 5w20.

Heck if you’re brave you can even use 0w30 or 5w30 in any vehicle that calls for 0w20 or 5w20. The differences are not actually that big.

 

It’s like people come on these sites and lose their common sense. The winter weight is marketing crap. When have you ever seen any oil get thinner when it’s cold?

 

[QUOTE="

Mixing 1 qt of 0w20 with 6 qt of 5w30 won’t be an issue, especially if it’s the same brand.[/QUOTE]

I've mixed brands of the same viscosity many times. I know different Brands have different additive packages but if I had a quart of Rotella gas truck left the store stopped selling I mixed it with 5 qt of super tech, nothing bad happened.

 

Yup.

 

I would agree unless you live in a cold climate. I can tell you the engine in my truck didn't like the 5w30 synthetic I have in it now during last winter when it got to be -15 one morning. This summer with still the same oil the truck is fine.

 

Your opinion but my statement comes from 30 years of training, certification and experience in the professional automotive field. I've delt with many oil viscosity issues sinse OBD11. It may not mechanically effect the engine but it can as far as driveability concerns. Some Jeep models wiil even set DTC's for viscocity concerns.

One thing I personally don't agree with is service intervals. I don't think I will ever go 10-15K miles between oil changes. I still do my oil and filter every 6000 miles with Tire Rotation. Especailly taking into concideration I use a remote start all through the winter. More hours than miles it seems for me.

 

I live in a hot climate. I run 5w30 synthetic in my 2GR.

You can use almost any weight oil in this engine. Anyone who thinks otherwise really needs to work on their critical thinking skills.

0w20 works just fine in my wife’s camry. After 10K miles the oil is nice and thick still. After 3K highway miles the 0w20 in my Tacoma was coming out with the consistency of water, not good. 0w20 is not good for an engine that has full torque at 4,500 RPM.

If you are tuned with KDMax or anything else that adjusts the redline higher, you absolutely should not be using 0w20 if you live in a hot climate.

 

To the OP. You are overthinking it. Add a quart to every change. Or use all 6 at the same time. What ever helps you to sleep better at night. Taco will not care. Non-synthetic oils cannot be run for 10K, 5K is a good interval for dino/semi-syn oils. You did not say what oil type you have.

One of the reasons (besides fuel economy) car makers spec 0w-20 vs 5w-20 is that 0-20 is available ONLY in synthetic flavor, while where are there semi-syn 5w-20. They do not want people running semi-syn 5w-20 for 10K miles.
Also, API weight is a range. There are 5w oils that almost as thin as thicker 0w-20. I have posted some examples before.
But here are some more:
https://pqia.org/mobil-1-advanced-fuel-economy-0w-20-advanced-full-synthetic-motor-oil/
M1 AFE 0w-20
Viscosity
Standard
Mobil 1
Status
Viscosity 100°C cSt
6.9 to <9.3
8.7

Viscosity 40°C cSt
–
46.0

Viscosity Index
–
170

Cold Crank Viscosity at -35°C
6,200 Max
5,287


https://pqia.org/castol-gtx-magnatec-sae-5w-20-full-synthetic-motor-oil/
Castrol GTX Magnatec 5W-20 Synthetic
Viscosity
Standard
Castol GTX Magnatec
Status
Viscosity 100°C cSt
6.9 to <9.3
8.3

Viscosity 40°C cSt
–
46.4

Viscosity Index
–
155

Cold Crank Viscosity at -30°C
6,600 Max
4,601

Castrol is actually a bit thinner at start up temp!

My wife's RAV4 calls for 0w-20. She is currently on 4K+ of Havoline 5w-20 High Mileage. Engine does not leak or use oil, but it is at 110K miles. I got 5w-20 HM at $5 for 5 quarts clearance sale. Why not use it for a 5K miles? Next oil change will be Idemitsu 0w-20 ($=another $5 for 5 qrts Autozone clearance). Will run that for 8K miles.

Taco will get 0w-20 Valvoline Full syn next time ($12/ 5 quarts).

Chrysler minivan will get a cocktail of Quaker State Full Syn 5w-30 (3 qrts left over from its current oil change) and 3 qrts Shell dino 5w-30. Will run it for 6K miles. Unless we do a lot of heavy loaded family trips. Then I will change at 5K.
Still have another 200 qrts of $5-$15/5 qrts clearanced synthetic oil to work thru, so I have not decided what I will feed them next.

Son's Veracruz will get Valvoline 5w-30 full syn. Manual calls for 5w20. But boy is very hard on his car (technically, a stepson, so I did not get a chance to teach him when he was younger). 5w-30 will him give a margin of safety if he waits too long to tell me that he needs an oil change (oil becomes thinner as it wears down and additives break down).

I have used 5w-30 full synthetic in Alaska for years for years. I doubt many posters on this thread started their cars at 20F below 4 months out of the year. Without the block heater. My little Kia Spectra 4-banger started right up.

PS for everybody's education. Petroleum Quality Institute of America. Tests of oils on the market.
https://pqia.org/
https://pqia.org/passenger-car-motor-oil/

PPS additive clash is a real thing, if you mix different brands, so just ran them for less time than you would all oil of the same brand.

PPPS most oil makers but oil additives from other companies (Afton, Lubrizoil, etc) as well.

 

I see you point as far as oil and ambient temps. Some manufactures recomend this but stay with their specifications.

 

Yes, there is. But oil weight IS a range.
https://pqia.org/passenger-car-motor-oil/

 

If in warranty, sure. If not, then the selection should be determined by UOA.

 

0W-20 will be slightly more efficient

 

This has been a pretty good and opinionated topic thus far. But what I don't get is what is the big deal about NOT useing the recomended oil. I mean, warrenty or not it's what the manufacturer calls for. Guarenteed not to damage the engine and runs at it best preformance driveabilty and economy wize. So, why not just run the called for oil(s). Just saying.

 

FOOD FOR THOUGHT. I MEAN OIL FOR THOUGHT.

One of the most common questions that I get is that, well, I took my care in for an oil change and the technician told me that instead of that thin, watery, 0-20, 5-20 or 5-30 that the manufacturer recommends, you need something this is seriously going to protect your engine.

You need 20-50, 10-40, some of these really thick oils. Don’t believe it. Modern engines are different than older engines and going to a thicker oil, it can lead to all kinds of problems. Number one, it can lead to poor circulation in the engine because it’s too thick.

That poor circulation can lead to problems that we see here. We cut a valve cover apart. This area in here that’s all clogged up – that is part of the breather system for the crank case. We had to put new valve covers in the engine because of this crud.

We can see over there that we have another valve cover all gunked up with sludge and so on. Why does this happen?

Back in the day when these oils were really popular, engines were made very differently. The clearance between bearings and so on inside the engine, between the cam shaft and cam bearing, or the crank shaft and connecting rods bearings, we could probably have measured them using an old fashioned feeler gauge.

But today, engines are built using modern technology, computer controlled machining, lasers to measure things and so on. So the net result is that these modern engines are much more precise. They fit better. The object of oil, the number one things is to move between moving parts and keep those parts from touching one another.

When we have smaller spaces, we need thinner oil to fit through those smaller spaces. Suppose you put a thicker oil in a modern engine. One of the things that’s going to do is increase oil pressure. Variable valve timing works off oil pressure so you might wind up with a check engine light and a code for the variable valve timing, which could lead to some expensive repairs.

The other thing is that oil is the oil thing that cools bearing inside the engine. Anything that’s lubricated is cooled by the oil. And when we increase oil viscosity, what we do is slow down the movement of the oil and that means that the parts inside the engine are going to run hotter because there’s less oil flow and that means more wear.

My recommendation, stick with what the vehicle manufacturer recommends. They spend millions of dollars figuring out what was right for your engine.

If you have a question of a comment, drop me a line, right here at MotorWeek.

 

Bearing clearances with a feeler gauge? BS. That article is garbage.

 

The whole issue centered around the point that I didn't want to discard the oil as it was NIB. I asked if there would be an issue with mixing 1 qt of the 5W30 in with 5 qts of 0W20 during subsequent oil changes. I order my oil in bulk to save on shipping so I have plenty of 0W20. Then like all oil threads it went .

 

It would have to be plasti-guage.

 

Because OP did not want to discard perfectly good oil.
And manufacturer only worries about the warranty period, not about you keeping your truck running for 300K miles.
Toyota calls its transmission fluid "lifetime". Would you run it without changing? Or change it at 50K or change it at 150K while replacing a grenaded transmission??

 

Autozone puts oils on clearance sales in November, $2 a quart to start with, then down to $1 a quart. I had loaded up on synthetic oils for $10 to $5 a jug.
Edit Walmart clearanced Castrol gold bottle and GTX last winterfor $3 to $2 a quart.
https://bobistheoilguy.com/forums/threads/walmart-castrol-gtx-clearance-ymmv.365471/

 

Some Jeep models also have Lifetime ATF. I kinda like it. It's next to impossible to even check, let alone fill the ATF where they locate the service port. I love engineer's, NOT.