use 10w-30 in place of 5w-30?

Maximus96

Diamond Member
Nov 9, 2000
5,388
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i have a bunch of chevron brand 10w-30 oil left over from my old car. can i use it in place of the 5w-30 that i normally put into our 06 nissan murano? we live in the bay area, ca so i don't think cold weather and viscosity is a problem.
 

HarryLui

Golden Member
Aug 31, 2001
1,518
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91
Read your owner manual. There is usually a section that tells you what oil you can use.
 

TridenT

Lifer
Sep 4, 2006
16,800
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I wouldn't do it... I'll use what is exactly recommended for my car because... oh snap, it's supposed to be done that way.
 

Vette73

Lifer
Jul 5, 2000
21,503
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yes 10w30 should meet the same standards as 5w30 just will not go as low temp. For your area the lowwer end of the 5 or 10 eight should not a issue.
 

earthman

Golden Member
Oct 16, 1999
1,653
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71
Won't make any difference whatsoever. The higher number is what matters when the car is warmed up.
 

Zenmervolt

Elite member
Oct 22, 2000
24,514
36
91
10w30 will be perfectly fine provided that it meets or exceeds the API service specifications outlined in your car's owner's manual. If you lived somewhere that had very low temps commonly, then there might be issues, but 10w30 should be good down into the 20's.

ZV
 

fleabag

Banned
Oct 1, 2007
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here is the better question, why would you use the higher viscosity oil (the W part) when you can use the lower one? I mean if they're the same viscosity when they're warmed up, and they generally choose the oil with a lower cold viscosity for cold climates, what would be the need for a higher cold viscosity then? I'd have figured that since things would have contracted so much at low temperatures that they'd use an oil with a higher viscosity at low temperatures, not lower.. Yes I understand moving parts at a high viscosity in frigid temperatures would be a major problem but what about the wear and tear of using a lower viscosity?
 

Zenmervolt

Elite member
Oct 22, 2000
24,514
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I'd have figured that since things would have contracted so much at low temperatures that they'd use an oil with a higher viscosity at low temperatures, not lower.. Yes I understand moving parts at a high viscosity in frigid temperatures would be a major problem but what about the wear and tear of using a lower viscosity?

1) All oil, even multi-grade oil, is thickest when cold and thinnest when hot. The weight range (e.g. 5w30) is not a description of absolute viscosity, but rather of viscosity characteristics. It means that, when the oil is cold, it behaves substantially similarly to a straight 5 weight oil and when the oil is hot it behaves substantially similarly to a straight 30 weight oil. This means that, even though it thickens when cold, it doesn't thicken as much as straight 30 weight would and that, even though it thins when warm, it doesn't thin as much as straight 5 weight would. Even when using 5w30 oil, it is thicker (more viscous) when cold than it is when hot.

2) The reason that lower weights of oil are preferred in very cold environments is because the higher an oil's viscosity, the more it resists the oil pump's efforts to build pressure. The thicker the oil, the longer it takes for the finer parts of the engine, such as the valvetrain, to be brought up to operating oil pressure. Lower weight oils allow the engine to "pump up" to operating oil pressure faster. This effect is especially pronounced in very cold climates. The oil's natural tendency to thicken when cold is more than sufficient to account for the increase in tolerances due to cold parts contracting even when using oils with very low cold weights.

ZV
 

Bignate603

Lifer
Sep 5, 2000
13,897
1
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here is the better question, why would you use the higher viscosity oil (the W part) when you can use the lower one? I mean if they're the same viscosity when they're warmed up, and they generally choose the oil with a lower cold viscosity for cold climates, what would be the need for a higher cold viscosity then? I'd have figured that since things would have contracted so much at low temperatures that they'd use an oil with a higher viscosity at low temperatures, not lower.. Yes I understand moving parts at a high viscosity in frigid temperatures would be a major problem but what about the wear and tear of using a lower viscosity?

The oil doesn't necessarily stabilize at the same temperature during all seasons. The oil temperature in most vehicles doesn't necessarily get up to a certain temperature and stay there in all seasons. Most cars don't have an oil cooler or a thermostat to regulate oil temperature so the temperature may fluctuate depending on the air temperature surrounding the oil pan. Because of this, car companies look at the operating oil temps for a variety of conditions and select the range of oil that provides good lubrication at the max and min air temps that they design the car for.

If his car calls for a certain oil viscosity range then that's what should be used. For cold air temps he probably can probably get away with a thinner oil than is speced out for his car and a thicker oil during warm parts of the year. However, I'd be wary about saying he should consider deviating from what his manufacturer recommends for the whole year.
 

fleabag

Banned
Oct 1, 2007
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1) All oil, even multi-grade oil, is thickest when cold and thinnest when hot. The weight range (e.g. 5w30) is not a description of absolute viscosity, but rather of viscosity characteristics. It means that, when the oil is cold, it behaves substantially similarly to a straight 5 weight oil and when the oil is hot it behaves substantially similarly to a straight 30 weight oil. This means that, even though it thickens when cold, it doesn't thicken as much as straight 30 weight would and that, even though it thins when warm, it doesn't thin as much as straight 5 weight would. Even when using 5w30 oil, it is thicker (more viscous) when cold than it is when hot.

2) The reason that lower weights of oil are preferred in very cold environments is because the higher an oil's viscosity, the more it resists the oil pump's efforts to build pressure. The thicker the oil, the longer it takes for the finer parts of the engine, such as the valvetrain, to be brought up to operating oil pressure. Lower weight oils allow the engine to "pump up" to operating oil pressure faster. This effect is especially pronounced in very cold climates. The oil's natural tendency to thicken when cold is more than sufficient to account for the increase in tolerances due to cold parts contracting even when using oils with very low cold weights.

ZV
If it's all relative, then how would one find an oil consistency so that it's the same consistency when it's hot and cold? If using an arbitrary scale, where 10 is the consistency when hot, for a 5w-30 oil, what would the consistency be when @ 50F? If that 5w-30 is a 20 when @50F and a 10w-30 is a 30 when @ 50F, what is preventing the use of 0w-30 in place of the 5w-30 then? I mean after all it's not like the 0w-30 when @50F is going to be thinner than needed when it's hot, right? So really, from the sound of it, you can always use the lowest "W" viscosity since it will never be less than the viscosity when it's warm..
 

Zenmervolt

Elite member
Oct 22, 2000
24,514
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If it's all relative, then how would one find an oil consistency so that it's the same consistency when it's hot and cold? If using an arbitrary scale, where 10 is the consistency when hot, for a 5w-30 oil, what would the consistency be when @ 50F? If that 5w-30 is a 20 when @50F and a 10w-30 is a 30 when @ 50F, what is preventing the use of 0w-30 in place of the 5w-30 then? I mean after all it's not like the 0w-30 when @50F is going to be thinner than needed when it's hot, right? So really, from the sound of it, you can always use the lowest "W" viscosity since it will never be less than the viscosity when it's warm..

1) We're not talking about differences between 0 and 50 degrees Fahrenheit when talking about multi-grade oils. An oil's weight is determined through a series of tests according to the SAE J300 specification. This test specifies a cold temperature and acceptable absolute viscosity information for an oil to carry a certain grade rating. For example, in order for an oil to carry a 5w30 rating, that oil must:
- Pass the 5W weight criteria for SAE J300
- FAIL the 0W weight criteria for SAE J300
- Pass the 30 weight criteria for SAE J300
- FAIL the 40 weight criteria for SAE J300

The winter weight tests occur between -10 and -40 centigrade and the standard weight tests occur between 100 and 150 degrees centigrade. At a mere 50 degrees Fahrenheit, pretty much any oil is going to be operating sufficiently close to its winter weight rating to be considered to be operating as though it were a straight winter weight oil.

2) It's not possible for an oil to be the same viscosity at all temperatures. Physics doesn't work like that. No oil will ever be the same consistency at all temperatures. It is the nature of fluids to increase in viscosity when cold and decrease in viscosity when hot.

3) Reasons for not using, say, a 0w30 instead of a 5w30 is that the greater the range between the winter weight (the "5w") and the standard weight (the "30"), the more viscosity modifiers that must be added to the oil. More viscosity modifiers means less base oil stock and consequently means less ability to lubricate as well as less ability to absorb contaminants safely without becoming acidic.

ZV
 
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Bignate603

Lifer
Sep 5, 2000
13,897
1
0
If it's all relative, then how would one find an oil consistency so that it's the same consistency when it's hot and cold? If using an arbitrary scale, where 10 is the consistency when hot, for a 5w-30 oil, what would the consistency be when @ 50F? If that 5w-30 is a 20 when @50F and a 10w-30 is a 30 when @ 50F, what is preventing the use of 0w-30 in place of the 5w-30 then? I mean after all it's not like the 0w-30 when @50F is going to be thinner than needed when it's hot, right? So really, from the sound of it, you can always use the lowest "W" viscosity since it will never be less than the viscosity when it's warm..

For someone that's so focused on fuel efficiency I'm surprised you're not proposing the thinnest oil possible. Oil functioning at the correct viscosity will have less parasitic drag on the engine while still providing good lubrication. Suggesting that they use a thicker oil than necessary would lower fuel efficiency.
 

fleabag

Banned
Oct 1, 2007
2,450
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3) Reasons for not using, say, a 0w30 instead of a 5w30 is that the greater the range between the winter weight (the "5w") and the standard weight (the "30"), the more viscosity modifiers that must be added to the oil. More viscosity modifiers means less base oil stock and consequently means less ability to lubricate as well as less ability to absorb contaminants safely without becoming acidic.

ZV
So is the use of synthetic 0W-30 going to be better overall in terms of lubrication and efficiency as the use of 5w-30 dino oil? It sounds like to me you are saying that a straight 30 oil is going to last much longer than a 5 or 10w-30 oil would.. How much worse is a 0w-30 going to be in comparison to a 5w-30? Also is the increase in viscosity modifiers when going from 5w-30 to 0W-30 going to be higher than 5w-20 to 0w-20?


For someone that's so focused on fuel efficiency I'm surprised you're not proposing the thinnest oil possible. Oil functioning at the correct viscosity will have less parasitic drag on the engine while still providing good lubrication. Suggesting that they use a thicker oil than necessary would lower fuel efficiency.
I didn't suggest using a heavier weight oil...:hmm:
 

overst33r

Diamond Member
Oct 3, 2004
5,761
12
81
For someone that's so focused on fuel efficiency I'm surprised you're not proposing the thinnest oil possible. Oil functioning at the correct viscosity will have less parasitic drag on the engine while still providing good lubrication. Suggesting that they use a thicker oil than necessary would lower fuel efficiency.

Car manufacturers are doing precisely this. Most cars these days use 0 or 5W-XX to get better mpgeeez.
 

Bignate603

Lifer
Sep 5, 2000
13,897
1
0
I didn't suggest using a heavier weight oil...:hmm:

You didn't, but typically you're going nuts about every possible drop of gas you could save to the point where you want to start removing your power steering. For something that actually is a reasonable thing to think about when you're maintaining your car I'm surprised you didn't even mention fuel efficiency when picking oil.
 

Arkaign

Lifer
Oct 27, 2006
20,736
1,379
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1) All oil, even multi-grade oil, is thickest when cold and thinnest when hot. The weight range (e.g. 5w30) is not a description of absolute viscosity, but rather of viscosity characteristics. It means that, when the oil is cold, it behaves substantially similarly to a straight 5 weight oil and when the oil is hot it behaves substantially similarly to a straight 30 weight oil. This means that, even though it thickens when cold, it doesn't thicken as much as straight 30 weight would and that, even though it thins when warm, it doesn't thin as much as straight 5 weight would. Even when using 5w30 oil, it is thicker (more viscous) when cold than it is when hot.

2) The reason that lower weights of oil are preferred in very cold environments is because the higher an oil's viscosity, the more it resists the oil pump's efforts to build pressure. The thicker the oil, the longer it takes for the finer parts of the engine, such as the valvetrain, to be brought up to operating oil pressure. Lower weight oils allow the engine to "pump up" to operating oil pressure faster. This effect is especially pronounced in very cold climates. The oil's natural tendency to thicken when cold is more than sufficient to account for the increase in tolerances due to cold parts contracting even when using oils with very low cold weights.

ZV

ZV, this is kinda off track of the current discussion, but wanted your opinion.

I have the '08 Focus S 2.0 Duratec (16v DOHC i4, 10.0 CR), and the factory oil was Ford Syn-Blend 5w20. After the first oil change I dumped the synblend and have been using Mobil 1 SuperSyn 5w20. Seems great, but should I stick with this or consider other options?
 

LTC8K6

Lifer
Mar 10, 2004
28,520
1,575
126
Car manufacturers are doing precisely this. Most cars these days use 0 or 5W-XX to get better mpgeeez.

They have gone to lower W numbers, actually. -20 instead of -30, to get the better economy. The first number probably doesn't affect FE much, if at all once the engine is warm.

Ford issued a TSB recommending a switch from 5W-30 to 5W-20 on many engines going way back. The 3.8L V6 in my 1995 Taurus was included, for example.
 

WhoBeDaPlaya

Diamond Member
Sep 15, 2000
7,414
402
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Ford issued a TSB recommending a switch from 5W-30 to 5W-20 on many engines going way back. The 3.8L V6 in my 1995 Taurus was included, for example.
They did the same thing for the 3.9L V8 in the 1st generation Lincoln LSes.
 

fleabag

Banned
Oct 1, 2007
2,450
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They have gone to lower W numbers, actually. -20 instead of -30, to get the better economy. The first number probably doesn't affect FE much, if at all once the engine is warm.

Ford issued a TSB recommending a switch from 5W-30 to 5W-20 on many engines going way back. The 3.8L V6 in my 1995 Taurus was included, for example.
I wonder if Honda has done the same with their 90s civics.. The reason why I ask is because despite the Honda D engine being in the '88-'05 civics, it's only the '01+ civics that mention 5W-20 while the previous civics mention 5w-30..
 

BassBomb

Diamond Member
Nov 25, 2005
8,390
1
81
my 02 civic said 5W20 but 5W30 was allowed but only for one change (never consecutive)
 

PlasmaBomb

Lifer
Nov 19, 2004
11,636
2
81
Posted by fleabag
I didn't suggest using a heavier weight oil...
You didn't, but typically you're going nuts about every possible drop of gas you could save to the point where you want to start removing your power steering. For something that actually is a reasonable thing to think about when you're maintaining your car I'm surprised you didn't even mention fuel efficiency when picking oil.

He didn't suggest anything because he has only come off his ban...
 

PlasmaBomb

Lifer
Nov 19, 2004
11,636
2
81
I wonder if Honda has done the same with their 90s civics.. The reason why I ask is because despite the Honda D engine being in the '88-'05 civics, it's only the '01+ civics that mention 5W-20 while the previous civics mention 5w-30..

Dropping an oil grade at operating temp (40 -> 30, or 30 -> 20) reduces fuel consumption by about 2% according to castrol. While it may not be much in real life, it can squeeze you down a bracket with regard to taxes in the euro zone... (where tax is based on g/km and 1-2 g/km can be important).

Changing the ecu setup/oil/gearing is cheaper than other options.