If a guy was typically running 5w-30 synthetic in the winter and 10w-40 synthetic in the summer, why not just use a 5w-40 synthetic year around? What are the downsides, if any?
5w-40 synthetic for year round use?
- Thread starter alyaz
- Start date
My diesel truck in signature use 5w-40 or 15w-40 year round in TX because that is the requirement for diesel truck.
So, it depends on what type of vehicle are we talking about.
Otherwise, it is just a philosophical discussion which is what you probably intend to do anyway.
So, it depends on what type of vehicle are we talking about.
Otherwise, it is just a philosophical discussion which is what you probably intend to do anyway.
No, not trying to get the oil debate going, just trying to find out if I am missing something here. I have run 5w-40 year round in diesel generators, diesel boats, gasoline UTV’s etc, all without issue. However, before continuing on just thought I would check. Guess my lack of understanding is around the ‘5w’ portion of the 5w-40, during summer use. All that really means is that it flows easier when cold, right? So once you get up to operating temperature that becomes mute, doesn’t it?
So you know about “the oil debate”? You learn fast. Your statement above is relatively correct except that it’s not about flow but rather about cranking and pumpability. But yes the oil is a 40-grade in both instances.
And it becomes moot, not mute.
And it becomes moot, not mute.
Copy thanks. Is there a way to close the thread?
I hope not
In your cases above, unless you want to change the oil at every season, then the use of 5w should reduce the need for OC every season.
I am not talking about the cars/trucks oil that need to be changed due to mileage anyway and that happen during season change anyway.
I am not talking about the cars/trucks oil that need to be changed due to mileage anyway and that happen during season change anyway.
Kestas
Staff member
I can think of two downsides to making this switch. One is the oil needs more viscosity improver, which is not a lubricant, thus reducing some lubricating properties of the oil package. The other is that 5W-40 shears down toward 5W-30 with time.
DON'T see your location BUT a 5-40 is made from 5W then LOTS of viscosity improvers bring it to a 40W at its spec!! lots of motorcyclist note issues with a 5-40 because it gets "weaker" sooner + of course a shared oil supply is harder on oils
This application would be for an ATV, where I generally change the oil every 50 or fewer hours.
Is this a shared sump application?
It has a wet clutch, but the 5w-40 is approved for wet clutches.
I use 5w-40 Delo400 full syn in all my outdoor toys/equipment- Yamaha outboard, ATV, jet ski, riding mower, etc.
I run Rotella T6 5W-40 in all my motorcycles, my boat and my Jeep all year round. Not a reason in the world to change grades for a season as long as the winter rating of the oil is proper for the extreme cold. The higher number does not matter once the engine is warmed up regardless of temperature.
In general, you are correct for short OCI's in engines easy on oil. Typically a 15W40 will stay in grade longer than a 5W40 will though, especially in a common sump geared motorcycle and should perform better in high temperature, high stress conditions.
Make your decision based on what you think your oil temperature is.
