15w50 Mobile 1 To Think For LS6?
So dose anybody else run 15w50 in a LS1 or 6 without any issues?
I live in Houston. When it is hottest it is maybe 100*F (although very rarely up to 110's*F). The oil temperature is going to be at least double that at operating temperature, and it isn't going to be hugely different whether the ambient temp is 60*F or 100*F if your coolant temps are taken care of... this assumes you aren't beating the car on a road course. Obviously if you are seeing very high oil temps from extreme use that is a different issue, but the correct answer would be oil cooling not thicker oil. This is in large part due to higher weight oils only having very marginal improvement in viscosity (less thin) over lower weights at very high temperature, but significantly worse viscosity at low temperature (too thick).
As far as the actual topic, if you were running a synthetic my blanket type answer would be that you should run more or less as little cold viscosity as you can since no oil is going to be too thick at ambient cold start. The answer is a little different with conventional oils because of the way they are formulated is a bit different and they are conceptually like the weight cold with VII's to make them perform similarly to the hot weight at temp (and so larger spreads are somewhat less than ideal and the oil will migrate towards the cold "weight" over time as the VII's are depleted).
German Castrol 0W30 is very popular around here because it is thin when you need it to be thin (at cold start) and is slightly thicker than an average 30 weight at operating temperature (really like a light 40). I run 5W30 Pennzoil Platinum year round here in Houston as it is nearly as thin as 0W cold.
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