HDEO too much of dichotomy?

[mechanicx]

With HD oils you have primarily 15W40 conventional and then 5W40 group III synthetic. It seems they need the 40 grade but does anyone else think there should be a 15W40 synthetic that is on the light end of 15W and heavier end of 40 grade, or maybe a 10W40 synthetic? To get a 5W40 with group III it seems you need to use a good amount of VII. And some of these seem to shear at least in gasoline engines. Unless you are trying to start a diesel in very cold temperatires I'm not really seeing the need for the 5W grade rating.

With spark ignition engine oils the grade spread didn't really change much from conventional vs synthetic. Is it that diesels fuel shear the oil less? If that is the case then why not a 10W40 conventional HDEO? Or would this have negative effects on volatility.

It just seems HDEO comes primarily in 15W40 and then 5W40. There must be different requirements for diesel vs gas but I'm not clear on what they are. Otherwise there wouldn't be two standards for spark ignition and compression ignition and they could be rolled into one.

 

[440Magnum]

Its been a while since I read up on it, but I don't think that Rotella T6 (for example)uses much in the way of VI improvers. Its technically a group III base, but its the Shell XHVI (extreme high viscosity index) base that is really pretty far beyond your average group III base in performance. As the name implies, its got a very high "native" viscosity index to start with.

T5, on the other hand, is available in 10w30 and 10w40 grades, and conventional Rotella is available in 15w40. About the only thing they don't have is a thin-side oil, like a 5w30 or 5w20. But then that's not their target market.

I agree its a little unusual that thesynthetic HDEOs are pretty much limited to 5w40, but I guess the market just isn't large enough to warrant anything else... yet.

 

[addyguy]

There are some companies that make 10W-40 HDEO's. Petro-Canada up here has a couple, but there definetly aren't many.

I suspect a lot of 15W-40's have flow/pump characteristics closer to a 10W oil, but the stick with the 15W-40 designation to not cause a mix-up between HDEO's and 10W-40 PCMO's, which were common up until 10 years ago.

There are very few 15W-40 PCMO's, if any, so a 15W-40 is automatically recognized as a 'diesel' oil right away.

 

[ARCOgraphite]

I would think the raison D'etre of synthetic 5w-hdeo is for cold starting of med and light duty diesel - hence the 5w. HD diesel would not be shut down in cold service unless for repair or long layover. 10w offers no large advantage over the 15w. I think even though the slack wax base group iii+ has a great VI vII are still required. Unless you have a tricky dumbell blend VII are requied in limited qty even in a PCMO 10w-30 PAO syn. Look up Chevron PAO base stock VI, they are typ WAY under (numerically less than) the final blend VII.

 

[rslifkin]

Of course the oils still need VII, but less than they would for a dino oil of equivalent viscosity spread, for example.

Personally, I like the 5W-40, as I wouldn't want to start my Jeep in 20* weather with a 15W-40 in there, but don't want to run a xW-30 either.

 

[440Magnum]

Originally Posted By: ARCOgraphite
HD diesel would not be shut down in cold service unless for repair or long layover.


That's getting less and less true as more and more areas pass "no idle" laws. I recently noticed that truckstops with overnight parking now aircraft-style HVAC hoses to be connected to sleeper cabs so operators can stay comfortable in the sleeper with the engine off.

 

[m37charlie]

Look at this list of MB228.5 HDEOs:
http://bevo.mercedes-benz.com/bevolisten...ent_action=show

They are all HDEOs, mainly 10W40 with some 10W30 and 5W30 and a couple of 5W40s.

Charlie

 

[lipadj46]

Originally Posted By: m37charlie
Look at this list of MB228.5 HDEOs:
http://bevo.mercedes-benz.com/bevolisten...ent_action=show

They are all HDEOs, mainly 10W40 with some 10W30 and 5W30 and a couple of 5W40s.

Charlie


OK but try to get those in the USA, I assume that the OP was talking about domestically available HDEOs.

 

[bloc0102]

Originally Posted By: mechanicx
With HD oils you have primarily 15W40 conventional and then 5W40 group III synthetic. It seems they need the 40 grade but does anyone else think there should be a 15W40 synthetic that is on the light end of 15W and heavier end of 40 grade, or maybe a 10W40 synthetic? To get a 5W40 with group III it seems you need to use a good amount of VII. And some of these seem to shear at least in gasoline engines. Unless you are trying to start a diesel in very cold temperatires I'm not really seeing the need for the 5W grade rating.

With spark ignition engine oils the grade spread didn't really change much from conventional vs synthetic. Is it that diesels fuel shear the oil less? If that is the case then why not a 10W40 conventional HDEO? Or would this have negative effects on volatility.

It just seems HDEO comes primarily in 15W40 and then 5W40. There must be different requirements for diesel vs gas but I'm not clear on what they are. Otherwise there wouldn't be two standards for spark ignition and compression ignition and they could be rolled into one.


Just a note on oil marketing...you can't market an oil as a 15W if it passes a 10W CCS.

 

[cheetahdriver]

Originally Posted By: bloc0102

Just a note on oil marketing...you can't market an oil as a 15W if it passes a 10W CCS.


i don't think that's right. the SAE J300 specs are "below xx" with no lower limit set for each XXw range. IIRC widman noted a Amsoil 10w40 that actually was more of a 5w40.

 

[jmac]

Originally Posted By: cheetahdriver
Originally Posted By: bloc0102

Just a note on oil marketing...you can't market an oil as a 15W if it passes a 10W CCS.


i don't think that's right. the SAE J300 specs are "below xx" with no lower limit set for each XXw range. IIRC widman noted a Amsoil 10w40 that actually was more of a 5w40.


The J300 specs I think are like that, but the rule is in the API cert rules, have found it before on their website, so if a fully formulated retail oil meets the cold flow requirements of say a 5w-30, to carry the API cert mark it cannot be labeled as a 10w-30 for instance. It has been talked about here before as well.

 

[TiredTrucker]

Originally Posted By: ARCOgraphite
HD diesel would not be shut down in cold service unless for repair or long layover.


I suppose a long layover is relative. A lot of states and cities now require that heavy truck diesels cannot idle more than 10-15 minutes in an hour, regardless of weather. A lot of heavy trucks with 14L, 15L, and 16L engines are shutting down for several hours no matter the temps. Partly to comply with idling laws, but also to conserve fuel. Most of these trucks are using 15w40 grp II or maybe blends. Some are going with the 5w40 synthetics.

 

[bloc0102]

Originally Posted By: jmac
Originally Posted By: cheetahdriver
Originally Posted By: bloc0102

Just a note on oil marketing...you can't market an oil as a 15W if it passes a 10W CCS.


i don't think that's right. the SAE J300 specs are "below xx" with no lower limit set for each XXw range. IIRC widman noted a Amsoil 10w40 that actually was more of a 5w40.


The J300 specs I think are like that, but the rule is in the API cert rules, have found it before on their website, so if a fully formulated retail oil meets the cold flow requirements of say a 5w-30, to carry the API cert mark it cannot be labeled as a 10w-30 for instance. It has been talked about here before as well.



Correct, not sure how it works with independent marketers that aren't API Certified, such as Amsoil. If they're a member of ILMA, their ethics codes may apply.

 

[XS650]

Originally Posted By: cheetahdriver
Originally Posted By: bloc0102

Just a note on oil marketing...you can't market an oil as a 15W if it passes a 10W CCS.


i don't think that's right. the SAE J300 specs are "below xx" with no lower limit set for each XXw range. IIRC widman noted a Amsoil 10w40 that actually was more of a 5w40.


The text of the SAE J300 spec spells out that if an oil qualifies for the lower temperature xW spec it has to be labeled as such. Can't call a 5W-30 a 10W-30 and be in compliance with the requirements of SAE J300.

My copy of SAE J300 isn't new so the requirement may have changed, but I doubt it.

Under some conditions an oil that meets some xW temperature spec can be labeled as a straight grade oil. Most synthetic and some conventional straight weight oils could also qualify as some xW rating. IIRC, is has to do with whether VI improvers are used or not.