Question for oil experts

[kenimpzoom]

When the 10W30 oil breaks down due to degrade of the VII polymers, what weight is the oil?<br /><br />Is it 10W or something else?<br /><br />Ken

 

[JRJ]

Re: Question for oil experts

The weight can vary. Break-down is one of the reasons we change oil.

 

[Bob_VT]

Re: Question for oil experts

I was under the impression that oil got thicker due to contamination and lubrication properties are lost from that contamination. Additionally I thought heat was the biggest enemy to oil.<br /><br />I do know that we change oil too often mostly due to old school habits and the sales tatics of most oil companies.<br /><br />I thing if 10W30 breaks down I thought you loose the 10 portion (effectiveness) and retain the sludge of the 30.

 

[LubeDude]

Re: Question for oil experts

Originally posted by Bob_VT:<br /> I was under the impression that oil got thicker due to contamination and lubrication properties are lost from that contamination.

C&P<br /><br /><br />The pour point depressant additives in a petroleum oil are used up quickly. As these additives are used up, the pour point (and borderline pumping temperature) of the oil rises. In addition, after the engine heats up the oil is subjected to high temperature conditions that burn off the lighter molecules in a petroleum oil, causing it to thicken.

 

[TheOilDoc]

Re: Question for oil experts

Originally posted by KenImpZoom:<br /><br />When the 10W30 oil breaks down due to degrade of the VII polymers, what weight is the oil?<br /><br />Is it 10W or something else?<br /><br />Ken

That is a very complex question. Not only are there several ways for the viscosity improvers to break down (overheating, sludging, fuel dilution, oxidation, contamination, extended use, etc.) but each way will result in a different viscosity, either increasing it or decreasing it.<br /><br />For example things like fuel dilution can easily decrease viscosity. While things like overheating can easily increase viscosity. Yet fuel dilution accompanied by overheating could mask the viscosity to appear normal.<br /><br />Usually, in an engine in good condition without fuel dilution, overheating, sludging, or excessive contamination, the viscosity improvers just break down from use. In this case the viscosity will generally decrease.<br /><br />

Origianlly posted by Bob_VT:<br /><br />I was under the impression that oil got thicker due to contamination and lubrication properties are lost from that contamination.

Thickening of oil due to contamination is a property of the oil's dispersant depletion. As contamination increase the dispersants deplete, the oil thickens, and additional contaminates can no longer be suspended in the oil. This is when the oil loses its lubrication properties and wear happens.

 

[20/20]

Re: Question for oil experts

some folks think the oil itself has become thicker because it has turned black and looks like sludge. It really isn't the oil getting thicker but the amount of contamination added,{metal, carbon etc..}