J30 Oil type
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professordesign
- Posts: 9
- Joined: Tue Nov 19, 2002 8:53 am
- Car: J30
J30 Oil type
When I bought my my '96 J30 from an Infinity dealer two months ago the dealer put 5w-30 weight oil in it. The manual says not to use 5w-30 but 10w-30. The dealer says 5w-30 is what is standard at his dealership.Any thoughts on this subject?
All other thinsg being equal (same brand):
10w-30 is genererally a much better oil than a 5w-30.Its more stable, puts a lower varnish load on your engine (cuz less VII's).Also it will have somwhat better lubricity since the extra VII's a 5w-30 has over a 10w-30 displace some of the base oil.Also a 10w-30 is plenty thin for the winter anywhere but the northern US.
On a side note in most applications and locations a Xw-40 (suchas a 5w-40,10w-40,15w-40) oil is generally a much better choice when engine protection is your priority than the ofetn recommended Xw-30 oils.The reason is that a 30 weight oil will save maybe a fifth of a mpg a fact that is very important to car manufactuers struggling to keep their federally mandated CAFE mpgs down.Some of the penalites assed by the USA govt for exceeding CAFE are pretty expensive (100's of millions of $$) giving manufacturers a hi incentive to squeeze every drop out of a given design.The easiset and cheapest (since no cost to manufacturer) trick to achieve this is to lower viscosity recommendations.You will note that almnost all manufacturere have lowered their recommendations in viscosity significantly vs earlier year in US.
Some myth supporting this is out there (like "todays engines have tighter bearing clearnaces blah blah" but you will find that the viscosity recommendations are lower in teh exact same engines as made 15 years ago (the GM 3.8 comes to mind as just one example among many).Even the same engines that are recommended as 10w-40 or 20w-50 in France/Germany/Italy etc are recommend as 5w-30 year 'round here in US, the exact same engine!!!!:eek
Anyway, there are very few vehicles that wont benefit at least in some fashion (however minor) from a swicth to a Xw-40 weight oil in all situation but a northern winter.
In my Q (smashed 5 days ago:() I run/ran ValvolineSYnPower 5w-40 all year (Kentucky).
Fred...
10w-30 is genererally a much better oil than a 5w-30.Its more stable, puts a lower varnish load on your engine (cuz less VII's).Also it will have somwhat better lubricity since the extra VII's a 5w-30 has over a 10w-30 displace some of the base oil.Also a 10w-30 is plenty thin for the winter anywhere but the northern US.
On a side note in most applications and locations a Xw-40 (suchas a 5w-40,10w-40,15w-40) oil is generally a much better choice when engine protection is your priority than the ofetn recommended Xw-30 oils.The reason is that a 30 weight oil will save maybe a fifth of a mpg a fact that is very important to car manufactuers struggling to keep their federally mandated CAFE mpgs down.Some of the penalites assed by the USA govt for exceeding CAFE are pretty expensive (100's of millions of $$) giving manufacturers a hi incentive to squeeze every drop out of a given design.The easiset and cheapest (since no cost to manufacturer) trick to achieve this is to lower viscosity recommendations.You will note that almnost all manufacturere have lowered their recommendations in viscosity significantly vs earlier year in US.
Some myth supporting this is out there (like "todays engines have tighter bearing clearnaces blah blah" but you will find that the viscosity recommendations are lower in teh exact same engines as made 15 years ago (the GM 3.8 comes to mind as just one example among many).Even the same engines that are recommended as 10w-40 or 20w-50 in France/Germany/Italy etc are recommend as 5w-30 year 'round here in US, the exact same engine!!!!:eek
Anyway, there are very few vehicles that wont benefit at least in some fashion (however minor) from a swicth to a Xw-40 weight oil in all situation but a northern winter.
In my Q (smashed 5 days ago:() I run/ran ValvolineSYnPower 5w-40 all year (Kentucky).
Fred...
A little bit about how using synthetic oils, influence viscosity considerations:
I feel that 5w-30weight oils (at least as a syn) are an obsolete weight, despite their recent popularity with manufactueres.Why?, because you will <always> be able to get an oil that is better on one end of the performance envelope, than any given 5w-30 at the same price.
Example: You can buy a winter oil in a 0w-30 that will be a much better winter oil for the same price as its syn from same brand in 5w-30 yet the hard running protection will be equal.
Now the sharp reader will say: "AHA! Hypocrisy! Can't I now just use the arguments you used against 5w-30 vs 10w-30 with VII"S and their effects on your choice of 0w-30 over 5w-30?"
The answer is no, the reason is when you have syn base stokcs you need a lot less (if any) VII's to achive a given viscosity range (there is also such a thing as pour point depressents but I will leave them out to keep this discussion simple).So the differnce in non base lube addivtives froma 0w-30 to a 5w-30 is negligible making the 0w-30 a suoperior choice especially in winter.
On the other end of 5w-30 There is 5w-40 (for a long time the "standard" european grade, like our 10w-30 used to be here).
The 5w-40 (in a syn) wil cold start just as well as a syn in 5w-30 but provide superior film stregnth reserve for fully warmed up drving, and especially hi rev/hiload drving situations, .So the 5w-30 is obsolete here as well.There is abosulutely no need to run a 5w-30 if using synthetic oils for the reasons outlined above.
Fred....
I feel that 5w-30weight oils (at least as a syn) are an obsolete weight, despite their recent popularity with manufactueres.Why?, because you will <always> be able to get an oil that is better on one end of the performance envelope, than any given 5w-30 at the same price.
Example: You can buy a winter oil in a 0w-30 that will be a much better winter oil for the same price as its syn from same brand in 5w-30 yet the hard running protection will be equal.
Now the sharp reader will say: "AHA! Hypocrisy! Can't I now just use the arguments you used against 5w-30 vs 10w-30 with VII"S and their effects on your choice of 0w-30 over 5w-30?"
The answer is no, the reason is when you have syn base stokcs you need a lot less (if any) VII's to achive a given viscosity range (there is also such a thing as pour point depressents but I will leave them out to keep this discussion simple).So the differnce in non base lube addivtives froma 0w-30 to a 5w-30 is negligible making the 0w-30 a suoperior choice especially in winter.
On the other end of 5w-30 There is 5w-40 (for a long time the "standard" european grade, like our 10w-30 used to be here).
The 5w-40 (in a syn) wil cold start just as well as a syn in 5w-30 but provide superior film stregnth reserve for fully warmed up drving, and especially hi rev/hiload drving situations, .So the 5w-30 is obsolete here as well.There is abosulutely no need to run a 5w-30 if using synthetic oils for the reasons outlined above.
Fred....
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greg_atlanta
- Posts: 1111
- Joined: Tue Jul 23, 2002 4:37 pm
- Car: 2008 G35 Journey Sedan, silver/black (no sunroof), 1992 Q45 (in a past life)
5W30 is good for newer cars (what dealer normally sees) and 10W30 is better for older cars. Mobil 1 has just changed their labeling to reflect that on their synthetic line.
There's a big push to increase fuel economy and if the manufacturer finds a lighter oil is 0.1% better then that's what they'll recommend. The Acura RSX uses 5W-20 -- which is not available except in Honda brand oil.
I find that 5W30 conventional oil burns off faster than heavier oils (or synthetic oils). I have to check my oil level more frequently with 5W30 and occassionally top it off, whereas I rarely have to do that with 10W30 synthetic, even after long trips.
It's usually cheaper to bring your own oil anyways!!
There's a big push to increase fuel economy and if the manufacturer finds a lighter oil is 0.1% better then that's what they'll recommend. The Acura RSX uses 5W-20 -- which is not available except in Honda brand oil.
I find that 5W30 conventional oil burns off faster than heavier oils (or synthetic oils). I have to check my oil level more frequently with 5W30 and occassionally top it off, whereas I rarely have to do that with 10W30 synthetic, even after long trips.
It's usually cheaper to bring your own oil anyways!!