I just moved to Washington State from Georgia and am currently using Mobil 15W-50 on my built motor. Since it is a lot colder here and will be getting much colder in the following months I was curious if I needed to change to something else thinner. I switched to the 15W-50 after reading that it could help with the small leak I have on my TN turbo (seems to work as well no more oil in intercooler). I was using 0w-40 before.

 

i woudl run a 10-30 and you sould be fine

 

Contrary to popular belief the weathers here is WA aren't that bad. When I was in TN I was hurtin from the cold, WA winters are kinda mild.

 

I was curious too. It get kind of cold her in NM but nothing too harsh. My Z spits oil smoke randomly. I was guessing it was the turbo seals and was going to try a thicker weight next go round. (currently using Mobil1 10-30) With winter coming Im wondering if I should stick with this weight.

 

I run 5w30 in Winter and 10w40 in Summer. Seattle doesn't really experience that much severe weather. Yes, it's colder most of the year, but nothing drastic, for the most part.

 

Uhm your motor stays a fairly constant temp because of your cooling system. Unless you're having problems with getting your motor up to temp then changing the weight of your oil isn't going to do much.

The weight rating of your oil has more to do with the build of the motor than the temps you're running your car in. If you're on a stock block run what the factory recommends, if you're on a built motor run what the builder tells you to run. Plain and simple.

Also I wouldn't run Mobil 1, read the forums and you'll understand that Mobil 1 isn't the same oil as it used to be.

 

I read some and was under the impression that the Mobil 15W-50 was different than some of the other mobil oil that was crap. Kind of like how the Mobil 0W-40 gets good reviews. This is from the oil analysis thread.

 

Hey OP, where were u getting the oil leaks?

Also, GTM runs mobil 1 0w40 on their built motors so I dont see a reason why it's not good.