Switch to 5w20 for the winter?
 

I was wunning 5w20 for the first few changes until I heard about the smoking issues and then upped it to 5w30. Turbo finally shit the bed and I got it changed out just before I hit 60k miles a couple of months ago. I was thinking of switching to 5w20 for the winter but wanted to get some opinions before I do so. TIA.

Why were you running 5W20 in the first place? The manual states you are to use 5W30. In addition why would change to 5W20 for the winter time. The 20 indicates the viscosity of the oil while the 5 indicates the outside air temperature range of the oil.

My manual says 5w20 but there was some debate on that in another forum and supposedly it was an error. My thought was to use thinner oil for the colder months. Am I wrong to do this?

It is an error. You should be using 5w30 minimum. 5w40 is what a lot of dudes run.

The cold weight is all you should be worried about in the winter. In this case, they all start with 5 so there's not much difference. A better question would be "switch to 0w30 or 0w40 for the winter?"

No need to run different viscosity in the winter. That's the beauty of multiple viscosity oils...

Hmm how odd. My manual also says 5w30 for the speed trim. I know the manual they give us is for both the reg mazda3 so you gotta make sure anytime you use that thing to look for the "with turbo" indications. Last time i got my oil changed at my dealership, they were put 5w20 in mine cuz they thought it was a regular 2.3 mazda3 5-door. They were nice enough to re-drain it and put 5w30 syn like i had asked them to.

Also, the whole lowering the viscosity of oil during winter isnt required anymore i think... from what i understand oil has the 2 weights to act as "all season" i.e. act like a 5w during cold and 30w during hot, hence 5w30? They used to sell oil back in the day that only had 1 viscosity number then people did have to change it during climate changes.

OK, fair enough. I'll stick to the 5w30.

Ha 5w20. I'll never run anything less than 5w40.

I use 5W-40 all year round in New Jersey. 5W is for cold startups. After the car warms up, I want a 40 weight to keep up with the turbo heat.

I use 5w30 Royal Purple--car runs smooth as silk. I'd never run 5w 20...

5/40 would be my choice but you can also go 0-40 if you are concerned with the cold.

the 20 portion of your oil is determines how it acts in hot temps...ie when your car is already warmed up....the first number is telling you how it will act in cold temps....ie...when your car is cold....so...if you are really concerned about cold temps go with a 0w-30 or 40...dont reduce your second number...

You shouldn't get cold enough in East Fishkill, NY to have to use a 0W oil. When I had my S2000 and was living in Grand Forks, ND where it'd routinely get to -25 degrees F ambient at night and maybe warm up to above 0 temps during the afternoon in January and February, I switched from a 10W-30 to a 5W-30 in a car with a 11.1:1 compression ratio and had no issues with cold startups with a 5W. The coldest temps up in Fishkill are probably mid teens on average.