Quote from: Gjkrisa on December 27, 2016, 12:24:20 PM
I've used 0w30 in my Subarus and have always got a head gasket around the next or second oil change someone has mentioned this might create more oil pressure my Subarus are over 100k on had just had the head gaskets changed so I thought it would be fine using roral purple 0w30
Maybe it cleaned some stuff out.
But I've chosen to stay with 5w30 till someone else can prove the car will be fine with it.
I've owned two 2.2 imprezas .
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Not sure what you are talking about at all.....0w-30 or 5w-30 would not cause head gasket failure! period....At operating temp 0w-40 and 10w-40 have the same viscosity
At start up and when cold the 0W oil will flow faster with less resistance than a 5W or 10W.....At cold temps a 5W or 10W may be too thick to flow fast enough to vital engine parts which is why pressure is higher with cold temps, it is resistant to flow
Oil viscosity is determined by temperature....Temperature dictates viscosity
If your car recommends 5w-20 and you beat the crap out the car at a road course chances are you will have too low oil pressure because you've super heated the oil and it gets thinner which lowers oil pressure, to get the pressure back to what the engine needs you need to get a heavier weight oil
0w-30 would yield the same viscosity if driven super hard or in hot areas as 5w-20 if not driven hard for example.
Viscosity changes based on temp....When viscosity ratings are given there is always a standard temp constant
Just like fuel injectors are always displayed in flow at a given pressure....Change the pressure the flow changes....Standard fuel injectors are rated at 43.5 psi And I think oil is like 0c and 100c but I'd have to check
