Oil temp vs. ability to hold insolubles in suspension

wwillson

Staff member
Messages
3,738
Location
Naperville, IL
Does anyone know if there is a relationship between oil temperature and the ability of that oil to hold insolubles in suspension? Blackstone says that 0.7% is the safe limit for insolubles in a gasoline engine. It's a given that hot liquids are more soluble that cold liquids. Could it be possible that the "safe" insolubles limit in the cold of winter might be lower than in the heat of summer? Wouldn't it make sense that when oil cools down to an overnight low of say 0 degrees that some of the suspended insolubles might settle out of the oil? Conversely, wouldn't it make sense that suspended insolubles might not settle out durning the summer with an overnight low of say 70 degrees? If my hypothesis is correct wouldn't it then stand to reason that the limit for wintertime insolubles would be lower than summertime insolubles? Thanks, Wayne
 

Al

Messages
19,236
Location
Elizabethtown, Pa
Well its a logical well thought out question. I don't have the knowledge to determing how much of the dirt/insolubles are kept in suspension by the detergnet action and if the temperature of the oil really affects it a lot. My guess is that it probably doesn't matter a whole lot..and the reason I say that is that very rarely to they go over .6 . Now trucks (diesels) get way beyond that (and yess the composition of oil allows that) but just as in trucks there is margin of design in the oil and don't fortet the filter can change that dynamics. So a lot of wind by me [Roll Eyes] - but I'm willing to bet its not an issue. [Smile]
 
Messages
2,361
Location
Texas
quote:
Originally posted by wwillson: Does anyone know if there is a relationship between oil temperature and the ability of that oil to hold insolubles in suspension? Blackstone says that 0.7% is the safe limit for insolubles in a gasoline engine. It's a given that hot liquids are more soluble that cold liquids. Could it be possible that the "safe" insolubles limit in the cold of winter might be lower than in the heat of summer? Wouldn't it make sense that when oil cools down to an overnight low of say 0 degrees that some of the suspended insolubles might settle out of the oil? Conversely, wouldn't it make sense that suspended insolubles might not settle out durning the summer with an overnight low of say 70 degrees? If my hypothesis is correct wouldn't it then stand to reason that the limit for wintertime insolubles would be lower than summertime insolubles? Thanks, Wayne
Wayne, it is an intelligent question. However, I think you are thinking about water and its properties, temperature changes will make some things precipitate out of water. Engine oil may be another matter. I think when oil gets too much in it, the insolubles will come out, but I think that that oil pump stirs the oil too much otherwise to do this. Also, I think unless the detergents were exhausted that suspeend the insolubles they would stay in suspension no matter what the temp. Also if this was the case members that winter in Canada would report massivie accumulations of sludge in engines from insolubles coming out of solution in the oil. Doesnt seem to happen unless something is wrong with the engine or the oci has been extremely overextended or the engine has been operated at too high a temp. Just my 2 cents. Dan
 
Top