So winter is coming up and it gets pretty cold in WV. I have some amsoil 5w-40 that my brother gave me and my question is can I use this safely in my FC?

Basically is 5w40 too thin of oil for a S4 1.3 NA ?
Im thinking since its an older car I should probably do 10w30 (compared to 20w50 summer) but since it gets so cold and the oil tends to flow slower and thick and i figured 5w40 would not do this. Whats your opinion?

 

From the FAQ:
Can I use synthetic oils in my Rotary engined car?
Yes and no. Mazda officially does not recommend the use of synthetic oils in rotary engines, however, long term and racing use has shown that the better synthetics (Redline, Amsoil, Neo, Royal Purple, Mobil1) are perfectly fine to use in a rotary engine, and will generally result in a 1 to 2% horsepower gain. However use of poor quality synthetics (like Valvoline, Castrol Syntec, Havoline, Etc) will result in build up due to high ash content left from these oils when they are burned. It is believed that is why Mazda did not recommend synthetics, because the couldn't pick favorites.

I've never been a fan of synthetics, although they do have their benefits under certain operating conditions, so I have used only Dino oil in all my vehicles with no problems, but if you have the oil available, it shouldn't be a problem. Mazda recommends a 5-30 when under freezing temps, so the 5-40 qrade will be fine.

 

I just run delo400

As far as your oil... What do you think the W stands for?

 

10w/30 will cover you from -20° to +90°F...also according to the FSM.
I run it pretty much year round unless there is a long road trip during the summer...then I switch to 20w/50.

 

Yeah I know 10w30 is good pretty much year round, I know synthetics are fine in a rotary . I was mainly asking if 5w40 would provide good protection. My understanding of the 5w40 is: it is a 5 weight oil that act likes a 40 weight? I just didnt want it to be too thin

 

10w30 and call it a day.

 

The W stand for winter.

It tells you the viscosity at low temperatures like a cold start up. The next number tells you the viscosity at high temperature like after the car is warmed up.

Anyways 5w-40 would be fine.

 

It's a multi\-viscosity oil. the first number is cold viscosity, the latter is operating temp. So 5W30 will better (in theory) in winter because while it is cold, the viscosity is very thin so it can coat your parts faster. Then, when it warms up, it will thicken and add a better film for wear.
Just don't go blasting around before the motor warms up completely.
http://www.upmpg.com/tech_articles/m...ity/index.html

Just for the record, I use high quality full synthetics for every fluid, always.