I'm currently running 5w30 Mobil 1, say I switch to 5w40 Rotella will this hinder performance n/a or boosted and mess up the engine in anyway? I heard going to a heavy grade reduces gas mileage and because its a thicker oil won't the engine work harder thus creating higher oil temps? Any suggestions would be awesome!!
The thicker viscosity create for a very minimal decrease in gas mileage yes. But, the temps of the oil run cooler than a thinner oil, as well as hold up to higher engine temps due to running it hard or high loads, much much better. The pros of thicker oils far outweigh the cons, of maybe one 1 MPG.
Just remember though, you are in a sometimes very cold climate. You need to select your weights accordingly.
That is why there is a chart that shows the heat ranges of different oil weights.
Down here in the summer, I run 20w-50 in the colder months, 10w-40 to 15w-50.
Having your oil reach the temp where it liquifies and offers no proection is very bad. Thin weight oils will always do that before thicker weight oils. Higher ZDDP content also adds another level of protection.
American blends, you have to really know where to look. European blends are much better. As their weights decrease, they increase the level of ZDDP. They aren't restricted by the EPA. :eviltongue:
