Based upon used oil analysis it seems like no conventional 5w30 oils hold there viscosity completely for the average oil change interval (3000+ miles). When do you think a 5w30 becomes a 5w-20? 2000 miles or less? Do high mileage oils stand a better chance of maintaining viscosity? Thanks
Any dino 5w-30 hold it's viscosity??
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I think the best conventional holdsis viscosity is the castoral gtx if I remeber reading used oil analysis correctionly. But even High Mileage oils will shear down eventally.
High Mileage oils probably hold their rated viscosity better because they start out on the high end of their viscosity rating. I don't know if they will hold their viscosity better percentage wise or not. Some engines will beat up an oil worse than others.....so your question will be virtually impossible to answer. Just because an oil shears down in viscosity, doesn't necessarily mean that it will not protect your engine.
Most 5w30 are 20 weights by at least 3000 and maybe sooner. Doesn't seem to hurt though.
Are most 10W-40s down to 30-weight at operating temperature after a similar amount of use?
I believe that Castrol GTX holds its viscosity well. I used it for several used oil analysis and the viscosity was always in the 30wt range. This is in a V-8 with 4-5K OCIs.
I know that a lot of people who use 10w30 all year switch to 5w30 during the winter for better cold weather specs, I think that most conventional 5w30's are a 5w-20 by 2000 miles.
Triple_Se7en
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I think Citgo reaches 20W before I can throw the empty jug into the recycle bin... lol
Does this hold true for synthetic 5w30's?
I was going to write a message to agree with you that 30wt dinos don't hold viscosity and shear back to 20wts and proving it by linking to the used oil analysis section.
Problem is, there are several that have held their viscosity! Some have not, of course, but surprisingly several HAVE held their 30wt vis. Take into account fuel dilution and coolant leaking issues when perusing through used oil analysis here. It surprised me!
Problem is, there are several that have held their viscosity! Some have not, of course, but surprisingly several HAVE held their 30wt vis. Take into account fuel dilution and coolant leaking issues when perusing through used oil analysis here. It surprised me!
"Most 5w30's shear to a 20 weight"
A very common phrase around Bitog - you probably see it several times each week.
But, in the defense of 5w30's:
1. The 5w30 grade relies on VI improvers, same as 10W-40's, and the long, spidery chain VI molecules are prone to shearing.
2. GF-4 and API Starburst practically mandate a viscosity reduction, as friction modifiers are not the entire solution to beating the PAO reference oil by 1.5-2.0% in the 96 hour Sequence VIB fuel economy test.
3. Sure, a 5w30 generally shears about 1.0-1.5 cSt, from 10.5 down to 9.0-9.5 cSt. But, other than Redline 5W-20, name a 20 weight oil that actually runs above 8.5 cSt? So a drained 5w30 after a 3K-5K OCI is still thicker than any 5W-20 sitting in the bottle!
So, my viewpoint is that the shearing is simply characteristic of the 5w30 grade, it is not a negative factor, it is/was present during the various GF-4 engine wear tests and it also is evident in some very fine reports that we see on the used oil analysis forum.
So, if anyone views this shearing as a negative, my suggestion is run a SAE 30HD, that should protect your engine from the bogeyman that creates this nasty shearing!
A very common phrase around Bitog - you probably see it several times each week.
But, in the defense of 5w30's:
1. The 5w30 grade relies on VI improvers, same as 10W-40's, and the long, spidery chain VI molecules are prone to shearing.
2. GF-4 and API Starburst practically mandate a viscosity reduction, as friction modifiers are not the entire solution to beating the PAO reference oil by 1.5-2.0% in the 96 hour Sequence VIB fuel economy test.
3. Sure, a 5w30 generally shears about 1.0-1.5 cSt, from 10.5 down to 9.0-9.5 cSt. But, other than Redline 5W-20, name a 20 weight oil that actually runs above 8.5 cSt? So a drained 5w30 after a 3K-5K OCI is still thicker than any 5W-20 sitting in the bottle!
So, my viewpoint is that the shearing is simply characteristic of the 5w30 grade, it is not a negative factor, it is/was present during the various GF-4 engine wear tests and it also is evident in some very fine reports that we see on the used oil analysis forum.
So, if anyone views this shearing as a negative, my suggestion is run a SAE 30HD, that should protect your engine from the bogeyman that creates this nasty shearing!
Citgo brand belongs to Venezuela. Given the kind of crap that wacko president of theirs has been pulling, I won't give my business to that company for any products if I can possibly avoid it.quote:
Originally posted by Triple_Se7en:
I think Citgo reaches 20W before I can throw the empty jug into the recycle bin... lol
Maybe Citgo should close their Cicero, IL plant so you can feel better, Rizzo. Sheesh, give them a break and, oh, let's keep politics under "General Topics".
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