Amsoil??

[amsoilman]

ACerf



The difference between the XL 7500 oils and the other "long Drain" oils from Amsoil are a totally different makeup. The base stock as well as the additives are completely different. These XL 7500 oils were introduced specifically for the "Quick Lube" market.

They include 5W-20, 5W-30, 10W-30, and 10W-40 grades. They are designed for 7,500 mile or 6 Month Drain intervals, which ever comes first. Yes, they do have the API certification "donut" on the label. These oils would not, and should not be considered for the CTD engines, as they only have an API "S" rating, meaning they are for Spark ignited engines only.



Wayne

amsoilman

 

[RobertMiller1]

How do you extended drain interval guys address the fact that heat over time destroys the long chain polymers in multi vis oil?



One of the main reasons for changing multi vis oils is the break down of the added long chain polymers to the oil base. Over time these polymers can no longer "unwind" themselves, and you are left with a 10w, 5w or 15w oil.



I know of no oil analysis that addresses this very important subject.



at 600,000 miles, you have probably been running a 15w or lighter oil for 575,000 miles.

:--)



This last sentence is not gospel. But should be thought provoking!:-{} :-{}

 

[RobertMiller1]

turbos

turbos are a very good reason to go with a synthetic oil.



you really need the benifits of extended drain interval to justify the costs. If I can get the final questions in my mind answered about extending the interval ... Well I would prefer to go with a synthetic.

 

[Edward]

RobertMiller1

Originally posted by RobertMiller1

How do you extended drain interval guys address the fact that heat over time destroys the long chain polymers in multi vis oil?... .

at 600,000 miles, you have probably been running a 15w or lighter oil for 575,000 miles.

Robert

I haven't heard of this before but if it is true then that has to be some darn good 15w to go for 575,000 miles wouldn't you say?



Edward

 

[amsoilman]

I know of no oil analysis that addresses this very important subject.

RobertMiller1,



Every oil analysis done by a competent oil analysis lab will test the oil for Viscosity.



Example of history from a customer of mine:



Dodge CTD using 15W-40 with 8,923 miles on oil, Viscosity was

13. 15 cSt@100 C.



Same truck, same oil with 33,679 miles on oil, Viscosity was

13. 07 cSt@ 100C.



To be considered a 40 grade oil when "NEW" the Viscosity at 100 C. has to fall between 12. 50 cSt @100 C. and 16. 29 cSt @ 100 C.

So you see, this particular oil in this truck did infact have the Viscosity checked, and was found to be within the limits.



I do agree with you on the fact that multi-Viscosity oils use polymers in them, but in some high quality synthetic oils, the heat does not break them down as easily.



Wayne

amsoilman

 

[RobertMiller1]

"... I do agree with you on the fact that multi-Viscosity oils use polymers in them, but in some high quality synthetic oils, the heat does not break them down as easily... . " appears to be a more plausible answer. Will have to look into this further.



I am a big fan of synthetics, but the extended change intervals finds me cautious. The fact that the major manufactures (like cummins) do not support it.



But if it can be safely done for 2x or 3x, then the better synthetics have the potential of being cheaper and less poluting.

 

[JohnE]

A little misconception in some of the posts.



Adding long chaim polymers to LIGHT base stock oil increases the 100°C viscosity. I believe Torco first introduced multi-vis oils to the market back in the early 50's. Refining of base stock has improved as has the quality of polymer additives over the years.



Look at the life of modern day dyno oils in natural gas or LP fueled (spark ignition) engines. Initially the unstable polymers burn off and slightly decrease viscosity. As the hours increase the base stock degrades and viscosity increases significantly. Oil analysis on these engines is not based on TBN reduction, but on viscosity increase.

 

[JRG]

Break Down

I do agree with you on the fact that multi-Viscosity oils use polymers in them, but in some high quality synthetic oils, the heat does not break them down as easily.

I saw this in my fresh 383 stroker in my Landcriuser. The dino oil would drop pressure after a 30 min drive. Switched to synthetic 5w-50 ad it NEVER dropped again even after hours of run time.



I see the quandary, to spend the extra $ on oil that you may never see the benefit from because if you change the dino at reasonable intervals it may not make any difference.



I use synthetic based on first had knowledge as do most of the others here. There are however some that do not see a need to spend the extra 50% to gain 2-3,000 miles on a oil change (stock) I can respect that as I do understand it.



I will use the synthetic mostly because of turbo heat and my experience with "shear",or "breakdown" due to that heat. After all I have spent plenty on other "stupid things", just ask my bo... wife.



JRG