5W30 VS 10W30 above freezing temps

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westwind999

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I've been thinking about putting some 10W30 Rotella T or T5 in my car that is rated for 5W30 year around. Most of the specs don't really indicate what the viscosity would be when the temperatures are above freezing most of the time. How far apart would the 10W30 be VS a typical automotive conventional 5W30? Is there some possibility of seeing any increased wear due to the 10W30? If so, why?

I'm looking for facts, not what's in the owners manual as a general recommendation.

Thanks
 
I don't know about facts... I feel like this whole site is 99% opinion.

I've just started experimenting with 10W-30 for the summer time.
I have noticed on my particular car it runs quieter upon startup.
 
Originally Posted By: CELICA_XX
I don't know about facts... I feel like this whole site is 99% opinion.


It is.........that's why I always laugh when somebody wants facts.
grin2.gif
 
Originally Posted By: Merkava_4
Originally Posted By: CELICA_XX
I don't know about facts... I feel like this whole site is 99% opinion.


It is.........that's why I always laugh when somebody wants facts.
grin2.gif



And 99% of the folks who had facts have left.
 
Originally Posted By: Merkava_4
Originally Posted By: CELICA_XX
I don't know about facts... I feel like this whole site is 99% opinion.


It is.........that's why I always laugh when somebody wants facts.
grin2.gif



10.gif
 
Originally Posted By: SEMI_287
Originally Posted By: Merkava_4
Originally Posted By: CELICA_XX
I don't know about facts... I feel like this whole site is 99% opinion.


It is.........that's why I always laugh when somebody wants facts.
grin2.gif



And 99% of the folks who had facts have left.


The only facts are what you'll find in your owner's manual.
 
What's written in your manual is there in the manual...that's a fact.

However, it's written the way that it's offered generally for other than engineering reasons, oft political, and oft beancounters, and in the latter, laziness is common too, with charts and specs that are really decades old in cases.
 
IMHO, if I lived in Canada, which is colder than this years arctic Ohio weather, I would run the thinnest oil I possibly could to avoid as much cold startup wear as possible.

And yes, If you ask for an opinion, that is probably what we will get on BITOG....

If you want facts for your vehicle, run UOA's on the oil to see how the wear metals are trending with different brands and weights. That is about as close to fact as you are going to get.
 
Originally Posted By: Cooper

If you want facts for your vehicle, run UOA's on the oil to see how the wear metals are trending with different brands and weights. That is about as close to fact as you are going to get.


Nope.

http://www.bobistheoilguy.com/used-oil-analysis/

Originally Posted By: Doug Hillary

Secondly, it is easy to assume that by carrying out a UOA you will be able to determine how quickly the engine is wearing out. As well, if you change lubricant Brands you will be able to compare the wear metal uptake results and then make a balanced best lubricant choice to make your engine last longer.

Sadly that logic is seriously flawed.

Single pass (random) UOAs will provide some information regarding wear metals but unless you have a history of your engine’s performance up to around 1 million miles the results are simply that – UOA results! As an example a limit of 150ppm of Iron is a reality – after say 100k it means the lubricant should be changed and all is well. But what is the situation if you have 150ppm of Iron at 5k? Where would you look what would or could you do? So UOAs are really a diagnostic tool – one of many!

The other parts of the UOA Report will be much more valuable to you – it will tell you about the CONDITION of the lubricant and its suitability for further use. This will enable you to get the maximum safe use from the lubricant saving a valuable resource in the process.
 
10w30 is often recommended by manufacturers down to 0 degree Fahrenheit, while 5w30 is often cited as protecting down to -20 degrees Fahrenheit.

While this graph is pulled from Briggs and Stratton, it gives you a general sense of where oil protection/start-up lies across weights.

oil_viscosity_chart.jpg


All of which is to say, there is not much of a difference between 10w30 and 5w30 above 32 degrees Fahrenheit. There are many members on these boards who can offer their own anecdotal take, that in general you cannot tell the difference between the two oils during warmer summer temps.
 
There is more to cold start up wear than simple oil flow. Acid build up, condensation, cold parts, etc all play a role. Many manufacturers who recommend 5W30 also allow 10W30 down to 0*F.
Above freezing, you'll be hard pressed to see any difference between the two.

Regarding UOA's, we use them to measure wear all the time - it's a bad habit but it's tangible info we can look at and share. Even now I'll tell you that it's supposed to be used to check oil condition and then boast about single digit iron numbers in one of my Jeeps. We used to have a good member here named BuickGN. He and I had similar mind sets when it came to lubrication and he was also a racing enthusiast. I remember a real nice looking UOA he posted despite the engine running rough. Upon tear down, half a piston was in the oil pan.
I keep that in the back of my mind now when thinking about how good UOA's look.
 
Originally Posted By: Shannow
What's written in your manual is there in the manual...that's a fact.

However, it's written the way that it's offered generally for other than engineering reasons, oft political, and oft beancounters, and in the latter, laziness is common too, with charts and specs that are really decades old in cases.


touché Shannow I definitely see your point but I must say, if you have a warranty claim, your recipes better show you followed the mfr's/om recommendation.
 
Originally Posted By: westwind999
How far apart would the 10W30 be VS a typical automotive conventional 5W30?

Remember that you're not exactly comparing a 5w-30 SN/GF-5 to a 10w-30 SN/GF-5. You're looking at a CJ-4/SM 10w-30, which will be thicker than a "normal" 10w-30. Warranty and weather concerns aside, I can't see it being an issue.
 
Originally Posted By: crazyoildude
its not about facts its about what works for you..


Well actually, it is about the facts. How would I really know what's going on inside the engine? I mean, with either oil it's going to start and go OK but is it seeing more wear with the 10W30? I don't have a parallel universe to put different oils in and look into the future to see which one lasted the longest. Just because it works for a while and doesn't hammer and bang, doesn't mean that there isn't some long term damage happening.

Having said that, it looks to me based on the graphs of the different grades I would be seeing about 5 degrees C more viscosity using the 10W30. So if I'm starting the motor with 10W30 at 0C it would be seeing oil like it was -5C with the 5W30 auto oil. At operating temps the 10W30 is at about 12cSt VS about 10.5cSt for the 5W30. Not sure if maybe that gives me some marinal extra protection against viscosity breakdown on a hot day? Would there be a downside to 1.5 cSt higher at 100C? (Maybe .1% more fuel consumption?)

Any further thoughts?
 
Originally Posted By: westwind999
Originally Posted By: crazyoildude
its not about facts its about what works for you..


Well actually, it is about the facts. How would I really know what's going on inside the engine? I mean, with either oil it's going to start and go OK but is it seeing more wear with the 10W30? I don't have a parallel universe to put different oils in and look into the future to see which one lasted the longest. Just because it works for a while and doesn't hammer and bang, doesn't mean that there isn't some long term damage happening.

Having said that, it looks to me based on the graphs of the different grades I would be seeing about 5 degrees C more viscosity using the 10W30. So if I'm starting the motor with 10W30 at 0C it would be seeing oil like it was -5C with the 5W30 auto oil. At operating temps the 10W30 is at about 12cSt VS about 10.5cSt for the 5W30. Not sure if maybe that gives me some marinal extra protection against viscosity breakdown on a hot day? Would there be a downside to 1.5 cSt higher at 100C? (Maybe .1% more fuel consumption?)

Any further thoughts?


FYI, the visc calcs aren't accurate below 0C.
 
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