Does thicker synthetic oil leak out less?

[adreed24]

I recently found out, from this site, that fully synthetic oils can be thicker, or thinner, than others. For example, Citgo Superguard fully synthetic oil 10W30, is supposed to be thicker than Mobil 1 10W30, (not the new extended stuff, but the regular SuperSyn).

If it's true, that fully synthetic oil leaks more than conventional oil, the question I have is: Does the thicker fully synthetic oil leak less, than thinner fully synthetic oils?

How would the outdoor temperature factor in?

 

[dickwells]

Not necessarily, The higher oil pressure make make loose seals leak more, I have noticed this with my old 88 GMC truck with 220K miles. As to the effect of weather, cool weather will make the oil thicker for a longer period of time (warm up) so there may be more leakage.

 

[JonS]

Just because M1 says it is 10.0 cst at 212f, doesn't mean this is what your engine will see. Your engine might have the oil at 200f, then you could be at 12.0 cst. Plus, these are just an average number picked by the refinery.

 

[Curious Kid]

Viscosity is viscosity, though I recall something being mentioned about a synthetic oil having a greater tendency to seep it's way into the smallest of nooks and crannies. Is this true? - I haven't a clue.

One thing synthetic are known for is their inherently better cleaning ability over standard dino stock, which may remove fill depositis on a seal that may have once been thought to still be in good condition. This probably explains the leaking main seals on the engine in my used car that started a year or two after putting in synthetic oil. I'm not sure I'll ever get around to replacing them, but the small oil spots are nerving!

 

[Dr. T]

When those on the board say that one 30 weight is 'thicker' than another, they're talking minute percentages....or decimal points therein. This will not make a **** of a difference.

As far as leakage...? Who knows, maybe just like dino oils...if you have less of a leak with dino 20-50, then you may have a lessened leak with synth. of the same viscosity (compared to a 5-30 for eg).

 

[dickwells]

"When those on the board say that one 30 weight is 'thicker' than another, they're talking minute percentages....or decimal points therein. This will not make a **** of a difference."

Maybe, maybe not. We know that viscosity is a continuous range chopped into arbitrary segments for ease of characterization. This being the case a high viscosity 30Wt (11.9) is much closer to a low viscosity 40wt (12.1) than it is to a low viscosity 30wt (I can't recall but I am guessing 10.0).