esters in group III

Al

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Hopefully Molakule will post here. But I would think not. Esters are used in combination with PAO's to offset PAO's seal shrinkage properties. Besides Group III oils advertise (scam public) as "Synthetic Oil" [LOL!] -why would they want to subtract from their bottom line by giving the customer a "true" synthetic component. [ September 01, 2003, 07:11 AM: Message edited by: Al ]
 
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Yes, virtually all Group III based synthetic oils have some esters blended in. This is needed for solubility reasons and because Group III alone is just as poor at seal swell as PAO. The one exception that I know of is Shell Rotella T Synthetic. Shell blends some Group I in to get the solvency and seal swell needed.
 

MolaKule

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If you go to the interesting Articles thread and search on "Esters, General," you will see the ester most widely used for miscibility purposes:
quote:
Hydroxyalkyl Carboxylic ester... This ester is used in many motor oil formulations that contain PAO(s) and is used to increase the VI, cause a slight seal swell, adds miscibility (mixibility) for additives, increases oxidative stability, and acts as a Friction Modifier.
It is also used in Group III oils as well, as per G_MAN's comments.
 
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'Kule, This is not meant to be a silly question...I am actually quite serious...considering where a lot of esters come from, if German Castrol is, as we suspect, heavy in esters, why doesn't it smell like coconuts?
 

MolaKule

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Not all esters have an aroma. I have here at my fingertips a bottle of TMP esters, it is water clear and it has no smell to it. In my lab, I have a quantity of pentaerithyritol polyol ester of ISO 100 viscosity, and it does not have any aroma as well. Some vegetable and synthetic esters (such as flavorings) do have an aroma. Unhydrogenated soybean oil stinks like road kill. Most synthetic esters for motor oils, such as TMP, TME, PE, Di-PE, and even the di-esters have no discernable botique at room temperature. I think what you may be detecting by smell are the additives. Some additives vary from sweet to pungent. Solvent dyes have almost paint-like aromas in concentrated form.
 
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quote:
Originally posted by MolaKule: Not all esters have an aroma.
To add, not all esters have a pleasant aroma, either. "Eau de skunk" comes to mind... More on topic, Lubegard's products (heavy on synthesized liquid wax esters) smell like something that died and is rotting in the bottle. Anyone wanting to experience an example of an essentially odorless ester need merely pop the cap off a fresh sample of salad or cooking oil and inhale at the rim. ALL animal and vegetable fats are esters. [ September 01, 2003, 11:02 PM: Message edited by: Ray H ]
 
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