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Mixing Brands
- Thread starter artbuc
- Start date
Who said an engine will blow up though? Also that’s a pretty low standard to set. That would be like judging the food solely based on the fact it didn’t give you food poisoning.Engine didn’t blow up, wear levels were fine, id be cool as a cucumber seeing that report
How was your meal, sir?
Well, I didn’t die or get explosive diarrhea. So, A+!
- Joined
- May 27, 2002
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- 651
Some years ago I bought a new Volkswagen. In its manual there were recommendations on what oils should be used. The one thing I remember was that the owner was to select the proper oil and stick with it. No mixing. I've never seen that on other cars I bought.
Patman
Staff member
Long term members here will remember that when I would switch over a car to German Castrol 0w30 I would do something that I called the Patman flush. I would drain the old oil for about a half hour and then I would add 2L of Castrol 0w30 and idle the engine for maybe 30 seconds. Then I would drain that out for about a half hour. This way the engine would not have all that much of the previous oil left behind. I mostly wanted to do this because I wanted to see how well this oil held its viscosity so I didn’t want any of the previous oil’s viscosity to be a factor. GC 0w30 was such a radically different oil that it was a good idea for it not to get mixed with other brands, especially when running it for longer intervals right away. I don’t do this anymore but I do think about it from time to time.
Got it, I will not do it again. But,, talking about 1 qt out of 6 total. Not going to lose sleep over it.
You sir have been awarded the “BITOG Of The Day Award” just for mentioning the long venerated and coveted, “Green Elixir.”
JTK
$100 Site Donor 2025
For the guys that say absolutely no mixing; As mentioned by @BrendanC above, is this your belief for top up oil as well?
You're 1000 miles from home on a vacation road trip and you discover your 5qt sump is 1qt low. Are you driving from store to store trying to find the exact oil you have in the sump? That is beyond BITOG silliness that being the case and I've been around as long as the "Patman Flush".
I believe most of us BITOGers agree that we'd prefer not to mix different brands of oil on a fresh oil change. I know with my fleet I've done it many times when my stash of whatever was a quart lower than I thought and I had to top up with something similar.
You're 1000 miles from home on a vacation road trip and you discover your 5qt sump is 1qt low. Are you driving from store to store trying to find the exact oil you have in the sump? That is beyond BITOG silliness that being the case and I've been around as long as the "Patman Flush".
I believe most of us BITOGers agree that we'd prefer not to mix different brands of oil on a fresh oil change. I know with my fleet I've done it many times when my stash of whatever was a quart lower than I thought and I had to top up with something similar.
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4WD
$50 site donor 2025
OVERKILL
$100 Site Donor 2021
There's a chasm between the relatively reasonable position of "I try to avoid mixing when possible" and "I'm Slim Shady the Super Chemist and I'm making the ultimate oil by mixing 2 quarts of Synlube with 2 quarts of City Star and 2 quarts of Supertech, I call this the 2/2/2 Super Combo and my Blackstone UOA tells me it's the BEES KNEES!!!".
One can quite easily acknowledge that a mix doesn't carry over any of the approvals that the constituents each held while simultaneously holding the view that it's unlikely to hurt anything. It's not ideal, but it's unlikely to be detrimental.
Well I’ll blow some minds and make a few people upset. I have an old farm truck that gets “whatever is on the shelf” for oil. After every oil change in anything I own I always drain the empty bottles and jugs of the last drips into a single container. I also was given some empty Amsoil barrels to use for burn barrels. I turned those upside down and drained them, collected what came out. Anyway, my farm truck is currently running an oil concoction consisting of 0w20, 5w20, 5w30, 10w30, non detergent 30, and even a 2 ounce bottle of two stroke oil I found on the floor in the barn. There is semi synthetic, conventional, and full synthetic. Brands include Amsoil, Pennzoil, super tech, parts master, oreillys, valvoline, Mobil 1, Castrol, Convoy, Cenex auto gold, harvest king and probably a couple others I have forgotten. I had about 2.5 quarts of these oddball drippings and the rest (3.5 quarts) was 5w30 (still of various brands and varieties). It’s been 2800 miles and 17 months as of today. Oil pressure is fantastic, previously noisy lifter is quiet as a church mouse, so far not a thing wrong as far as I can tell. If it blows up tomorrow it’ll be hard telling if it was as from the oil or if it’s from 3 decades of abuse and neglect adding up. Now I would never do this in a vehicle or machine I truly cared about and wouldn’t recommend the same to others but I guess my point is, 1 quart to top off an engine that isn’t the same as what’s already in there is likely going to be just fine, don’t overthink it.
The truth about mixing oils is that any oil with an API license or otherwise passing ASTM D6922 is guaranteed to be miscible and not separate which would cause damage. However, as noted it does not guarantee that the resulting mixture meets any of the licenses, specifications nor approvals that the individual oils may meet or carry. It also does not guarantee that the mixture will qualify for any specific winter rating.
So make your own determination if that is important or relevant to you. Some boutique blenders state that their formulations are such that mixing is completely acceptable.
So make your own determination if that is important or relevant to you. Some boutique blenders state that their formulations are such that mixing is completely acceptable.
Patman
Staff member
I’m pretty confident in saying that most people on here who are embarking on a long road trip would have checked the oil and topped it off before leaving, so they would not find themselves in a situation like this. And if they had a vehicle that was a known consumer of oil they would have an extra quart or two in the trunk for those trips.
Even though my Civic doesn’t consume much oil (about half a quart every 5k) I still have extra oil in my trunk. When I buy a 5qt jug I only need 4.5 quarts for the oil change and the other half quart gets saved for later.
BrendanC
$100 site donor 2024
exactly right. every fluid gets checked and topped off in any of my vehicles before leaving for a road trip. both accords have a quart of HPL PCEO 5w-30 in the trunks just in case. my pickup has never burned a drop of oil so i just verify level and take off. if your vehicle burns that much oil it may be better to buy more than you need when you’re buying oil change supplies and keep the extra in your trunk.
Jackson_Slugger
$50 Site Donor 2022
I've heard recently that EM and SOPUS actually have a joint additive package venture so they are probably closely related as far as add-packs. Lake Speed the YTer is the source....
JTK
$100 Site Donor 2025
I was looking for more of a yes or no answer. This is BITOG. Silly me!
Having been here about 20 years, I always get a kick out of this topic.
I believe, I may be wrong, that you can mix any API SP rated oil? Certainly shouldn't be harmful, but certainly not ideal. If you're doing an OCI as per the manual, probably not an issue. Especially if you're just adding a touch to bring it to full.
To be honest, my sons Hyundai Santa Fe takes like 5.1 quarts. I have a few single Mobil 1 quarts that I just use to give the sump a "splash" to the Valvoline R&P to bring it to the full line. Not ideal, but doubt it hurts anything.
If it is really bad, my 10 year old Honda engine lawn mower is in trouble. It has gotten a little of this and a little of that every Spring.....some of the mixes were like 10 years old....
To be honest, my sons Hyundai Santa Fe takes like 5.1 quarts. I have a few single Mobil 1 quarts that I just use to give the sump a "splash" to the Valvoline R&P to bring it to the full line. Not ideal, but doubt it hurts anything.
If it is really bad, my 10 year old Honda engine lawn mower is in trouble. It has gotten a little of this and a little of that every Spring.....some of the mixes were like 10 years old....
I now do my elderly neighbors oil changes, in their 3 vehicles, a car, suv, and diesel pickup.
Told them that if they were picky about oil and filters, to bring me their favorites, or else just pick me up OEM filters to fit them, and I would use my oil choice, which is Mobil1 0W40 European in gas engines, and Valvoline Premium Blue 5W40 in the diesel. He laughed so hard, and told me he just put whatever he had around in the 3 of them, since they were new, and wasn't even sure what was in them currently. I found that funny, and glad he isn't on BITOG or his head may explode.
Told them that if they were picky about oil and filters, to bring me their favorites, or else just pick me up OEM filters to fit them, and I would use my oil choice, which is Mobil1 0W40 European in gas engines, and Valvoline Premium Blue 5W40 in the diesel. He laughed so hard, and told me he just put whatever he had around in the 3 of them, since they were new, and wasn't even sure what was in them currently. I found that funny, and glad he isn't on BITOG or his head may explode.
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