Can you mix 5w30 and 10w30?
 

So, i just put oil back in my car after drilling and tapping my oil pan. However, i got 3 quarts put in when i realized that one of them was 5w30 and the others were 10w30. They mustve gotten mixed up at autozone somehow. Anyway, should i drain $24 worth of oil or just run with it?

I don't see a problem with it.

ive done it lots of times with my old civic, i dont know what the effects are,
but i didnt see anything happen over the 2 years i drove it,
and i mixed alot, civic liked to leak oil from oil pan, so i added w/e i could find

It will make 7.5w30.

No you can't!

The Hydrocabons molecular structure is different, the 5W will seperate from the 10W. When this happens, out gassing occurs. This outgassing of Hydrogen will dry out your valve seals, and your Hydraulic lifters will collapse.

Same thing happens when you mix Synthetic with Dino oil...

Oh. I've never heard this. I guess the OP shouldn't do it then. Thanks for the info.

i just googled this for a few mintues,
everywhere i looked said its not a problem
i checked a few dif forums ,
as long as pressure is good,
there shouldnt be a problem.

jefe - please back up ur info, if u r indeed correct, ide like to have proof,
where did you find out about the hydrocarbons?

Done lots of reading on it and there is no problem with mixing.

I'd like to see whatever he's read to think they aren't mixable.

:friday:

well, i wont worry about it then. thanks for the help!

it's fine, makes the mixture whatever it mathematically comes out to be

:giggle:

Everyone is so serious around here lately...

IT WAS A JOKE PEOPLE

I can't believe people didn't get it. Read the whole post.

I hear your muffler bearings will seize and your airbag fluid will freeze up.

you know if this was posted on m.net, there would be a thread here making fun of it.

yeah, youre probably right... better to be safe than sorry?

Just curious....if mixing is ok then what what the hell is the point of selling all different types of oil like 5W30, 10W40, etc??? Also it was my car I think I would rather dump that oil put all the same type. Is $24 dollars worth of oil worth the cost of a motor if in case something did happen.

Zarish, you can't be serious. That's like asking "Why do they sell both Rum and Coke?" Just because the two are inter-mixable does not mean they are the same.

0w20 is a thin oil. 20w50 is a thick oil. Some engines require one, some engines require the other. That's why they sell both types. If you mix the two together, you will in fact get a homogeneous mixture rated somewhere in between the twp grades. The engine won't blow up, nothing will settle out of anything else, lifters will not collapse and seals will not fail.

@Joe Perez,

"Just because the two are inter-mixable does not mean they are the same."

This is exactly why I asked, your answer is within your own question. Anything can be mixed if you want to mix it, but that doesn't mean it will be ok to do so. You talk about rum and coke? Even rum and coke will effect your body and organs in a certain way, yes you will not die from it, but it will effect your organs in the long run. I know what you guys are saying, but I was just wondering how the oil mixture will effect the seals? There are two different viscosity oil in the engine flowing through. There is got to be more to this. Not to make an arguement out of it, but like I said I am curious to learn more cause I personally think its no simple as it has been made to look.

ok, simple english, all oil is the same basically, some thicker some thinner, you take two different viscocities and you mix them you will a third viscocity somewhere in between the two you mixed...does that make more sense?
not trying to be an ass, just trying to help you understand it

so what if I mix rum and coke with 5w30? what'll I get then?

We had a party last night for a bunch of new pilots who just qualified at the boat. It was a Big Lebowski theme. Everybody was drinking caucasian's and they ran out of Kahlua. Somebody mentioned just using cream and chocolate syrup, so that's what we went with... not bad.

Zarish, I think you might be missing a big part of the oil nomenclature. 10w30 doesn't mean it's half 10 and half 30. The viscosity of the oil will change as it's temperature changes. When the oil is cold, it's viscosity will be very thick, which aids in getting everything coated very quickly on startup. As the oil gets hot, it gets thinner, allowing it to flow better through the engine when it's running faster. That's why you should really let an engine get warm before you hammer on it.

I believe oil weight is measured at 0* and 100* for multiweight oils. That's celsius.

Why do you guys assume I or anyone else does not know what oil is or what viscosity is or that I am missing a big part of the nomenclature???? Anyways, I don't think you guys understand what I am asking. Next time you guys do your oil changes don't bother looking at what the tag reads, just put in any mixture of oil. A quart of 5W30, 10W30, 5W50, and another one of your choice. Who cares since its all the same anyways right??? Oh and forget about rum and coke, they are not even the same even though you mix it and drink it. If any of you ever are in a hospital and need blood, don't worry bout the blood they insert in you body, since the blood is all the same and the different blood types don't matter. Not trying to be an ass, but I do notice that on this forum you guys seem to know it all. Wonder why the forum even exist. Sorry if offended any of you guys, but this is the fact.

We assume that from the nature of your questions. That's the basics, so we figure coving all of them will net you where you want to be.

If your car is rated at 10w30, and you need a total of 5 quarts, than adding one quart of 10w30 and 4 quarts of say 40w50 isn't recomended.
It is probably better if you add oil close to your weight req.
IE: you need 10w30, so adding a bunch of 5w30 to your 10w30 wont do anything wrong. Adding 20w50 to it wont do anything wrong most likely, but why risk it?

We are all assuming the closer to the real req mix, the better, and the more of the right mix will allow you more breathing room to add diff. viscosities. But, it is all guesses as to what your motor will take.
1/5 being effed up has been proven not to really do much, especially since its only in 3 - 5k miles. Make it a habbit and who knows? change 4/5 of those quarts and see what happens. give us a good experiment to work with

"We are all assuming the closer to the real req mix, the better, and the more of the right mix will allow you more breathing room to add diff. viscosities. But, it is all guesses as to what your motor will take.
1/5 being effed up has been proven not to really do much, especially since its only in 3 - 5k miles. Make it a habbit and who knows? change 4/5 of those quarts and see what happens. give us a good experiment to work with"

I don't believe in mixing viscosities, so I am not the one who should be giving you guys the experiment to work with. Since most here think its ok, they have nothing to worry about and maybe one of them should try it and give us the experiment to work with...

I have made my point, and rest my case. Lets see who here wants to try running their motor this way and experiment.

Some advice to whoever likes mixing oils:

-Do not, however, mix synthetic and normal oils (unless the synthetic's manufacturer specifically says it's OK).

-Try to stick with the same brand and of oil since mixing brands might have different additives added to their oil and might not be compatible with another brands additives and minerals.

-Never mix detergent and non-detergent oils. An oil that is rated, say 10-30 or 20-50 with one that is rated, say, SAE30 or SAE20.

Try staying as close as possible with oil mixtures that are close to what is recomended run safely on the particular car, since after mixing two different oils you really don't know exactly what the resulting mixture's viscosity is.

No, you can't. It's impossible.

quick, someone tell zarish where 89 octane gas comes from.

whales

Considering what abuse our engines get, compared to the average use, we all should be running racing oils anyhow ;)
Ever considered that most racing oils seem to be 10-60 and the likes, pretty thick, pretty high temperature resistant.

Dont even know what i wanted to say from the start ;) but hell, climate can make you choose a different oil than recommended, just think before.

It really doesnt matter. I had an '83 Porsche with over 300k miles on it before I wrecked it. The motor casing was never opened up, not once. I just did regular maintenance on on it. Depending on the use of the car I would put different grade oils in it. When I wrecked it back in '04, I had 40 weight racing oil in it. Normally I ran 20w50. I will say the motor rev'd a tad slower and I got a tad less mpg with the heavier weight oil vs a 10w30 blend. But, who cares it was a Porsche. Now, we all have our Porsche kill stories, but there is something about owning one. Anyway, there was always talk among the Porschephiles that switch from dino to synthetic would ruin our seals. Not once did we ever see either affect our cars in a negative way.

But, if you are asking about grades of oil, viscosity and what ifs, then you dont need to run an aftermarket forced induction set up in your car. If you can't grasp simple oil concepts then may the Lord help you with anything REALLY difficult.

That sounds like an awesome party. Did you "do a J"?

It wont mess up your car at all. i had done that a few times. just make sure next time put the right oil in. lol we all have our moments

I had a 1981 Celica that leaked and burned oil like nobody's business. I was young and broke at the time and started reusing old oil. That car still ran when I donated it to charity. Had over 300,000 km. Pretty sure I mixed the oil couple of times. Never did change the filter.

Ok you got me beat. hands down. buddie of mine ran out of oil in his car, dumbass, and he was 40 mile from home and broke so he kept driving. when he did put oil in it, car ran fine.

lol thats funny. what did the charity think if there new BMW?:giggle: