Why specifically use 5w30 when you could just use 0w50 grade engine oil for all cars?

[ElChanclo]

This feels like a dumb question, I've obviously missed something here, but I can't get a straight answer from google.

If 5w30 is rated from -35c to 35c, and 0w50 is rated -40c to 50c, then why not just use the latter for most cars?

 

[rtv900]

because for one 0w-50 is probably double the cost
50 weight hot is still too thick for street use anyway so it won't perform as well. 50 weight is for track use where you're going to be running 300 degree oil. On the street you won't get over 220
5w-30 is the best all around oil for street use. It'll be fine starting up when it's 5 degrees F outside, and it'll be fine driving hard on the street when it's 95 degrees F out

 

[oddball]

The engineers spend quite a bit of time figuring out the right weight oil for a particular engine. It's not the "rating". The specific clearances they designed, the use for the engine, how it heats and cools, and extra features (various control solenoids, squirters, etc) in an engine will make specific viscosities preferable over others.
You *can* run any viscosity and it'll run just fine. Too thin and you risk bearing damage. Too thick and you risk things like cam phasers not working correctly.
That temp rating chart is just one - very minor - aspect of an oil. I don't think that chart is actually useful. I think all it's trying to say is the temp range over which the oil stays within its rated viscosity? or stays within a certain minimum and maximum viscosity? Regardless, it's not actually useful.
Getting a wider viscosity rating, like 0 to 50, requires a lot of chemistry magic, so those oils will be more expensive and will likely break down quicker. The 0 viscosity stuff is pretty new. It's "better" to use as narrow of a rating band as possible. 10w-30 has been around a very long time and is easy to make. The push to 0 weight is for fuel economy when cold.

 

[Thomby]

I asked something similar a while back, not about 50 weight, but 0-30 (or 0-40 if you want to go a bit thicker for track duty). IE keep the same weight but have it flow better at startup and while cold.

Getting a wider viscosity rating, like 0 to 50, requires a lot of chemistry magic, so those oils will be more expensive and will likely break down quicker. The 0 viscosity stuff is pretty new. It's "better" to use as narrow of a rating band as possible. 10w-30 has been around a very long time and is easy to make. The push to 0 weight is for fuel economy when cold.

This is similar to the answer I got: in a perfect world, at a given weight (-30 or -40), you'd want 0w over 5w or 10w, to minimize cold/startup wear. But in reality, it takes more additives to stretch the oil's behavior and get it to act thinner when cold while keeping its viscosity up high.

So like with many other things, there's a tradeoff, and the marginal wear prevented by going from 5w to 0w might not be worth the decreased life/protection at operating temp.

Better might be just to use remote start or let your car idle an extra minute at startup, don't wind the engine out til its fully warmed up, etc. Should cause less engine wear than 95% of cars out there that get cranked and driven hard ice cold, anyway.

 

[D.J.]

50 weight hot is still too thick for street use anyway so it won't perform as well. 50 weight is for track use where you're going to be running 300 degree oil. On the street you won't get over 220

I concur - unlikely to get over 220F oil temperature on street
Max oil temperature of 98C (208F) on a 1+ hour commute a few days ago

 

[rtv900]

Better might be just to use remote start or let your car idle an extra minute at startup, don't wind the engine out til its fully warmed up, etc. Should cause less engine wear than 95% of cars out there that get cranked and driven hard ice cold, anyway.

^this is actually worse of all. The oil is ice cold, the engine is turning very slowly idling, so parts oiled with splash get minimal lubrication and things like squirters basically don't work at all.
Driving conservatively until it's warmed up is by far the best policy for modern cars.

 

[Thomby]

^this is actually worse of all. The oil is ice cold, the engine is turning very slowly idling, so parts oiled with splash get minimal lubrication and things like squirters basically don't work at all.
Driving conservatively until it's warmed up is by far the best policy for modern cars.

I find it very hard to believe that idling is going to cause more wear than revving to a few thousand rpm while accelerating the weight of the car...the difference in load is huge.

I have seen this recommended in those "best way to warm up your car" articles, and they never have anything substantive, but always have something about how idling wastes gas. So I'm more inclined to believe that it's non-car people figuring the car will be fine either way, or they don't know/care about its condition in 50-100k miles, they just feel like idling is bad.

 

[Ohiocruiser]

I find it very hard to believe that idling is going to cause more wear than revving to a few thousand rpm while accelerating the weight of the car...the difference in load is huge.

I have seen this recommended in those "best way to warm up your car" articles, and they never have anything substantive, but always have something about how idling wastes gas. So I'm more inclined to believe that it's non-car people figuring the car will be fine either way, or they don't know/care about its condition in 50-100k miles, they just feel like idling is bad.

In what world do you consider "driving conservatively" means revving it to few thousand rpm?? Start the car. Wait ~30 sec for oil to reach every component it suppose to lubricate. Drive it, keeping rpm under ~1500, till the oil reaches operating temps (around 5min). At least that is what I do.

 

[Volfy]

This feels like a dumb question, I've obviously missed something here, but I can't get a straight answer from google.

If 5w30 is rated from -35c to 35c, and 0w50 is rated -40c to 50c, then why not just use the latter for most cars?

That chart doesn't tell the whole story. Personally, I do not like multi-viscosity oils with very wide spread, like the 0W-50. To achieve that rating, a 0w-50 starts with a base oil with very low VI (Viscosity Index), hence the 0W designation, which allow it to pump and flow well at low temp. However, such oil will thin out too much when the temp rises, to the point where your oil pressure will drop off excessively and the oil's film strength also reduces to dangerous levels, potentially allowing for metal-metal contact. To remedy that, the oil mfr add viscosity modifiers, typically long-chain polymers, which help the low-VI base oil combat further viscosity reduction at higher temp. In the case of the 0w-50, it will thin out no worse than what a straight 50-VI oil would at high temp (100C).

The problem is... the wider the spread, the more viscosity modifier has to be added. These polymers do wear out over time. When they lose their effectiveness, the oil regresses back to having the characteristics of the 0w bae oil. Personally, I wouldn't want to run that risk - on the streets, and especially at the track.

It's your car, so you are free to use whatever oil you prefer. My suggestion... if you do run something like the 0w-50, change it more often than you would oils with less spread. If you do track the car, change it right before the event.

 

[Thomby]

In what world do you consider "driving conservatively" means revving it to few thousand rpm?? Start the car. Wait ~30 sec for oil to reach every component it suppose to lubricate. Drive it, keeping rpm under ~1500, till the oil reaches operating temps (around 5min). At least that is what I do.

Eh maybe should've said couple thousand, point was that even "normal driving" is multiple times your idle rpm, and with significantly higher load (piston side load, bearing load, etc).

 

[Volfy]

^this is actually worse of all. The oil is ice cold, the engine is turning very slowly idling, so parts oiled with splash get minimal lubrication and things like squirters basically don't work at all.
Driving conservatively until it's warmed up is by far the best policy for modern cars.

That was the best policy even for older cars. The problem was that with dumb carbs, cars quite often wouldn't run worth a crap, sometime even on full choke. Then the 70's oil crisis and the subsequent mpg mandates made this problem even worse. To where a lot of cars simply could not be driven when stone cold. This was where the "driveway warm up" practice originated from. It had nothing to do with engine longevity. However, the motoring public took it as such and turned it into the myth that pervades even today. Even though sensor feedback and computer control now allow every single car to start&run just fine at arctic temps, I still see folks idle their cars pointlessly to "warm up".

 

[Snicklefritz]

That was the best policy even for older cars. The problem was that with dumb carbs, cars quite often wouldn't run worth a crap, sometime even on full choke. Then the 70's oil crisis and the subsequent mpg mandates made this problem even worse. To where a lot of cars simply could not be driven when stone cold. This was where the "driveway warm up" practice originated from. It had nothing to do with engine longevity. However, the motoring public took it as such and turned it into the myth that pervades even today. Even though sensor feedback and computer control now allow every single car to start&run just fine at arctic temps, I still see folks idle their cars pointlessly to "warm up".

Short drives are a thing that I really don't like. So, I would rather warm up at both ends of the short drive by idling. Better policy is to take a longer drive route to my destination. That way the engine seldom gets turned off before at least reaching operating coolant temperature. Until I got the GT1 with the "gauges" screen, I never even thought about oil temperature separate from coolant temperature. Since then, I've been rather obsessed with checking oil temperature. I won't, for instance, do a launch until the oil temperature reaches just below 200F. I won't even engage the turbos much if at all until then. The Premium doesn't come with the "gauges" screen, so, I only go by the coolant temperature gauge. I know about how long it takes the GT1 to get to full oil operating temperature, and I treat the Premium the same way, wait until Ima pretty confident that the time has passed long enough to get the oil temperature up.

 

[Volfy]

Short drives that don't let the engine get up to operating temp is a whole 'nother topic all together. It is a serious one that can land your engine in hot waters (silly pun intended), especially if you use a fuel with substantial ethanol content. See here:

Like you said, the best safeguard is to go for longer drives occasionally, instead of the driveway warmup.

 

[D.J.]

In what world do you consider "driving conservatively" means revving it to few thousand rpm?? Start the car. Wait ~30 sec for oil to reach every component it suppose to lubricate. Drive it, keeping rpm under ~1500, till the oil reaches operating temps (around 5min). At least that is what I do.

What oil temperature would you consider operating temps?

It takes quite a while for the oil to heat, longer than the coolant. See my chart on post #5
CVVT temperature is engine oil temperature.

This chart was me driving after about 120 seconds of starting...

Took about 20 minutes for oil to get to FULL operating temperature - while driving.

Here's a more zoomed in version of the same chart.
I started driving at about:
8:28am
8:33am 5 mins of driving oil temp is ~48°C (118°F) - coolant is at 60°C (140°F)
8:45am coolant finally reaches full temp
8:48am oil reaches full operating temp (20 min in this case).
9:10am trans temperature reaches stable temperature

 

[Ohiocruiser]

What oil temperature would you consider operating temps?

It takes quite a while for the oil to heat, longer than the coolant. See my chart on post #5
CVVT temperature is engine oil temperature.

This chart was me driving after about 120 seconds of starting...

Took about 20 minutes for oil to get to FULL operating temperature - while driving.

Here's a more zoomed in version of the same chart.
I started driving at about:
8:28am
8:45am coolant finally reaches full temp
8:48am oil reaches full operating temp
9:10am trans temperature reaches stable temperature

View attachment 84397

If the stock oil temp gauge is accurate, I would say it's in 160-170 degrees range. Takes me a while to get to 200, probably 20-30min. But it's not like I start flooring it as soon as it get there. My engine very rarely sees anything over 3500 anyway. But if and when I floor it, I make sure it's around 200.

 

[rtv900]

In what world do you consider "driving conservatively" means revving it to few thousand rpm?? Start the car. Wait ~30 sec for oil to reach every component it suppose to lubricate. Drive it, keeping rpm under ~1500, till the oil reaches operating temps (around 5min). At least that is what I do.

exactly. In comfort mode which is what I use when I'm just commuting or warming up, this car shifts around 1500 in general

To remedy that, the oil mfr add viscosity modifiers,

yep, exactly why those huge spread oils sound great but really aren't that great

Eh maybe should've said couple thousand, point was that even "normal driving" is multiple times your idle rpm, and with significantly higher load (piston side load, bearing load, etc).

you are conflating higher than idle rpm with some sort of damaging situation in an engine. This is not the case, that's why we have dual viscosity oil. It's perfectly safe to have "multiple times" idle rpm, which is basically 600rpm. The engine warms up 10x's faster which is what you want. Letting it sit and putter for 20 minutes is not a positive thing.

The problem was that with dumb carbs

I have a 1950 truck and this is the ONLY reason I let that sit and warm up, because I literally have no choice. If I drive it in winter temps and leave before a solid 10 minute warm up it will basically stall out at every stop and I have to flutter the gas to prevent it once I go into neutral and it drops to idle. Very difficult to do when you need to use the brake also. Often I'll have to use my left foot on the brake and flutter the gas pedal with my right. Totally miserable to do.
And agreed that is exactly why that ridiculous myth about warming up cars has stuck around for 30 years after carbs went away. Throttle body injection wasn't much better but once sequential port injection came about it was a game changer. Warm ups do nothing but foul up the oil, waste fuel and pollute needlessly.

 

[Volfy]

BTW, just because the temp at the oil temp sensor hasn't reached 200F doesn't mean elsewhere in the oil circulation path, it hasn't reached 200F (or whatever temp high enough to boil off entrained moisture).


Also, another way to look at idling vs. driving warm-up is to consider the amount of work done by the engine.

When idling, the engine is metering just enough fuel to do just enough work to overcome internal friction, just enough to keep the engine turning over. The very little fuel burnt means very little heat produced, which means the engine will warm up very slowly.

Once you start driving, the engine is doing actual work to move/accel the vehicle, which take much more fuel to produce much more heat energy to do much more work. Obviously a large portion of the heat energy is converted to mechanical work moving the vehicle. However, as much as we have improved the thermodynamic efficiency of the modern Otto Cycle gasoline engines, it is still only around 20-40%. That means more than 1/2 of the heat energy produced is "wasted". That heat either goes out of the tail pipe, or into heating up the powertrain and exhaust.

Obviously, a driver needs to balance between warming up the car as quickly as possible and not loading the engine too much before it has reached operating temps. So... go easy on the accelerator pedal and don't rev the engine excessively while the engine is still warming up.

 

[Thomby]

you are conflating higher than idle rpm with some sort of damaging situation in an engine. This is not the case, that's why we have dual viscosity oil. It's perfectly safe to have "multiple times" idle rpm, which is basically 600rpm.

It's not just the piston speed, but also the side load on the major thrust face. It's why cylinders wear into ovals. You don't think this will occur at a higher rate when the oil is 150 degrees below its operating temp and you have a load sufficient to accelerate the car's weight? Vs. nearly zero load?

 

[Ohiocruiser]

It's not just the piston speed, but also the side load on the major thrust face. It's why cylinders wear into ovals. You don't think this will occur at a higher rate when the oil is 150 degrees below its operating temp and you have a load sufficient to accelerate the car's weight? Vs. nearly zero load?

So, what are you saying? Are you warming your engine up for 30+ minutes before you drive? Or do you know some way to warm in up quickly to 200 without driving it?

 

[Thomby]

So, what are you saying? Are you warming your engine up for 30+ minutes before you drive? Or do you know some way to warm in up quickly to 200 without driving it?

I'm not saying to wait until full operating temp, but to minimize load at the most extreme temp. There's probably a diminishing return as you get further from ice cold, but it's hard to imagine a few minutes and 50-100 degree head start before putting a load on the engine isn't preferable...