quick YACT: 5W-30 or 10W-30?

[andylawcc]

let me get this straight,
5w-30 is less thick/viscous so it is better suited for small engine with light use.

10w-30 is a bit more viscous and is for heavier duty and/or older cars with high mileage.

correct?

 

[Eli]

No, that is incorrect.

They are both 30 weight oils. They have the same viscosity at operating temperature.

The "W-number" is an arbitrary number that has nothing to do with actual viscosity. It's a measure of the oil's Cold Cranking Simulator results. The lower the W-number, the better the performance at lower temperatures. IIRC, to qualify as a "10W" oil, it must score at least 2500cP @ -20ºF.

To answer your question, we need to know a little bit more information, like where you live.. for starters.

 

[Pepsi90919]

what does it say on the oil cap/owner's manual?

 

[Heisenberg]

Use whatever the manual says, although you could probably use either one without problems.

 

[Kipper]

I blend the two 1:1 for four quarts. I find that I burn less oil that way. If I go four quarts of 5W30 straight, I tend to end up with 1 QT/800-900 miles disappearing.

 

[SWScorch]

my car recommend 5W-30, although it says 10W-30 is acceptable during the summer

 

[isekii]

I did 10-w30, but now i'm using 5w-30.

 

[andylawcc]

Originally posted by: Eli

To answer your question, we need to know a little bit more information, like where you live.. for starters.

Toyota 1.8 EFI gasoline 4 banger . Horsepower: 105. Compression Ratio: 10.0:1
I believe the user manual recommends 10w-30
I currently living in Missouri. It has HOT summer and snowing winter.


right now I bought a 5Quart jug of 5W-30 Pennzoil and 10W-30.
I have been using 10w the whole time, and I did a 50:50 mixing for my last oil change just for fun.
I know it probably won't make a difference,
but doesn't less viscous means less friction(and protection)?

 

[Vette73]

I use Mobil 10W30 year round. I also, unless it requires soemthing different, use the same thing in all my customers cars/trucks.

 

[Eli]

Originally posted by: andylawcc

Originally posted by: Eli

To answer your question, we need to know a little bit more information, like where you live.. for starters.

Toyota 1.8 EFI gasoline 4 banger . Horsepower: 105. Compression Ratio: 10.0:1
I believe the user manual recommends 10w-30
I currently living in Missouri. It has HOT summer and snowing winter.


right now I bought a 5Quart jug of 5W-30 Pennzoil and 10W-30.
I have been using 10w the whole time, and I did a 50:50 mixing for my last oil change just for fun.
I know it probably won't make a difference,
but doesn't less viscous means less friction(and protection)?

Let me take this opportunity to repeat myself.

There is no difference in viscosity between 5W-30 and 10W-30. They are both 30 weight oils at operating temperature. Where they do differ, is in their cold temperature performance.

Pennzoil 5W-30 scores 6600cP @ -30ºF
Pennzoil 10W-30 scores 7000cP @ -25ºF

The lower the cP, the more fluid the oil is. As you can see, the 5W-30 is clearly more fluid at lower temperatures. The only difference you will see between these two oils, if at all, is slightly harder starts on cold mornings with the 10W-30.

They are nearly identical spec-wise. The Pennzoil 10W-30 is slightly more shear stable than the 5W-30. Definately use it over the 5W-30 in the summer time.

5W-30 should be acceptable in the winter; if you want to be hardcore you can get some 0W-30, but it is usually synthetic.

Yes, lower viscosity means less friction and generally less protection. But by using 5W-30 over 10W-30, you are not using a different viscosity. They just have a different "viscosity curve" through their operating temperature range.

I'm running 15W-40 in the 2.0L 3SFE in the Camry and in the HiPo Chevy 350 in my truck.

Yes, the Camry manual calls for up to a 50 weight oil in the summer time. So I'm actually mid-ground. I'm not sure what I'm going to use this winter.

I was thinking about Castrol 5W-50. It is synthetic, though.. Haven't decided if I want to bother, especially since the Camry has seen only conventional oil it's whole life.

We need to get the leaking distributor shaft fixed, at the least, before switching to syn.Protection > MPG, IMO.

 

[Kadarin]

The 5W-30 will flow better when the engine is cold, meaning it should help reduce wear when the engine has not warmed up yet.

 

[andylawcc]

Originally posted by: Marlin1975
I use Mobil 10W30 year round. I also, unless it requires soemthing different, use the same thing in all my customers cars/trucks.

did you ever have to use 5w-30 or other? I rarely see anything other than 10w-30 in most mechanic shops.



and thank you Eli for your detail reply.



anyway, one last thing if you don't mind.
does less viscous = less protection and more friction ? (yes, I got it, 10w-30 = 5w-30 for viscousity in operating temp)

 

[FrustratedUser]

Originally posted by: andylawcc

Originally posted by: Eli

To answer your question, we need to know a little bit more information, like where you live.. for starters.

Toyota 1.8 EFI gasoline 4 banger . Horsepower: 105. Compression Ratio: 10.0:1
I believe the user manual recommends 10w-30
I currently living in Missouri. It has HOT summer and snowing winter.


right now I bought a 5Quart jug of 5W-30 Pennzoil and 10W-30.
I have been using 10w the whole time, and I did a 50:50 mixing for my last oil change just for fun.
I know it probably won't make a difference,
but doesn't less viscous means less friction(and protection)?

Why did you even ask the question?

 

[Eli]

Originally posted by: andylawcc

Originally posted by: Marlin1975
I use Mobil 10W30 year round. I also, unless it requires soemthing different, use the same thing in all my customers cars/trucks.

did you ever have to use 5w-30 or other? I rarely see anything other than 10w-30 in most mechanic shops.



and thank you Eli for your detail reply.



anyway, one last thing if you don't mind.
does less viscous = less protection and more friction ? (yes, I got it, 10w-30 = 5w-30 for viscousity in operating temp)

Lower viscosity usually means less protection, but friction will also decrease, resulting in a (very slight, almost certainly negligable) MPG improvement. This is why Honda "recommends" xW-20 oils. Adequate? Perhaps. Ideal? Certainly not, IMO.

You can use 5W-30 all year around if you want to. It won't hurt anything, and you won't have to worry about buying different grades. As Astaroth33 says, it will help reduce wear on your engine at startup. If you're the type of person that starts it and goes, this could be quite beneficial.

 

[Vette73]

Originally posted by: andylawcc

Originally posted by: Marlin1975
I use Mobil 10W30 year round. I also, unless it requires soemthing different, use the same thing in all my customers cars/trucks.

did you ever have to use 5w-30 or other? I rarely see anything other than 10w-30 in most mechanic shops.



and thank you Eli for your detail reply.



anyway, one last thing if you don't mind.
does less viscous = less protection and more friction ? (yes, I got it, 10w-30 = 5w-30 for viscousity in operating temp)

I do use 5W30 in cars that have less then 6K. But anytime after 6-9K I switch to 10W30. Yes 5w30 flows a little better when cold, BUT its polymers have to stretch further to make it work as a 30 weight so it has a GREATER chance of breakdown in that matter. Kinda like stretching a rubber band 3 inches vs 4 inches. It might be able to do both, but the chance of the 3 inch breaking before the same 4 inch one is slimmer.


But keeping up with reg. oil changes is a MUCH better protection then trying to decide between 5w30 and 10w30.

 

[Eli]

Originally posted by: Marlin1975

Originally posted by: andylawcc

Originally posted by: Marlin1975
I use Mobil 10W30 year round. I also, unless it requires soemthing different, use the same thing in all my customers cars/trucks.

did you ever have to use 5w-30 or other? I rarely see anything other than 10w-30 in most mechanic shops.



and thank you Eli for your detail reply.



anyway, one last thing if you don't mind.
does less viscous = less protection and more friction ? (yes, I got it, 10w-30 = 5w-30 for viscousity in operating temp)

I do use 5W30 in cars that have less then 6K. But anytime after 6-9K I switch to 10W30. Yes 5w30 flows a little better when cold, BUT its polymers have to stretch further to make it work as a 30 weight so it has a GREATER chance of breakdown in that matter. Kinda like stretching a rubber band 3 inches vs 4 inches. It might be able to do both, but the chance of the 3 inch breaking before the same 4 inch one is slimmer.

This is true, and is why, At least in the case of Pennzoil, their 10W-30 is more shear stable than their 5W-30. When those polymers shear, the oil literally thins out and becomes less than 30 weight. Fortunately(depending on your point of view), you also have oil vaporization fighting to thicken the oil, so I suppose it kinda evens out, at least a little... assuming your engine is in pretty good mechanical shape and isn't diluting the oil with fuel.

I'm curious why you insist on 10W-30. You could be doing your customers a disservice, depending on where you live. I don't think 10W-30 would be appropriate for Northeast winters, for example.

But keeping up with reg. oil changes is a MUCH better protection then trying to decide between 5w30 and 10w30.

Absolutely.

Instead of fussing over the oil you use(as long as it is the proper viscosity..), spend a little extra time paying attention to your air and oil filters.

They are more important than the brand of oil you use.

 

[Vette73]

^


No, NO northeast. I agree. If you live in a REALLY cold place 5w30 (or even a Syn) would be called for. But I had my shop in Wilmington NC, no really cold snow days, just lots of heat. hence the 10W30 over 5w30.

 

[andylawcc]

Originally posted by: FrustratedUser

Why did you even ask the question?

doesn't hurt to ask a question right? beside, I also wanted to know the difference between the two, not just which one to use.

Kinda like stretching a rubber band 3 inches vs 4 inches. It might be able to do both, but the chance of the 3 inch breaking before the same 4 inch one is slimmer.

one of the best technical-to-layman analogy ever

Fortunately(depending on your point of view), you also have oil vaporization fighting to thicken the oil, so I suppose it kinda evens out, at least a little

whao....

 

[Slacker]

Go with the manufacturers recomendation