Switching from 0w-20 to 0w-30 experience

[tiger862]

30k worth of data on my Frontier 3.8 shows a loss of 1.5 mpg going up to a 30 grade oil from 20 grade. Same oil brand and series. I just changed tires and loss another mpg. With these fuel prices I will be going back to a 20 grade. I feel like there are millions of miles on a 20 grade oil from different manufactures without engine loss. Now what is interesting is this is city as hwy mileage is the same. For those that don't know I use my truck for work and put close to 400 miles a week with 60% city driving. Lots of stop and go with some idling mixed in.

19 mpg city and 24.3 mpg hwy on 20 grade
17.5 mpg city and 24.3 mpg hwy on 30 grade

1000 miles on new Firestone Destination LE 3 17.5 mpg with 30 grade.

Hopefully it will get better as I drove like a grandpa for last tank and got 17.8 and that was 100 miles on the hwy with cruise set at speed limit.

 

[EBruce]

After warranty I switched my 2019 Jeep Grand Cherokee Limited 3.6 V6 to 5-30 Mobil 1. Nothing changed except engine noise, it is more quiet for sure. Still getting 18/24 for fuel mileage. Here in NE Florida where the temps for the last month were mid ninties I feel like the 5-30 a better choice than 0-20. It's what the the same engine uses in many other countries, and earlier models of this PUG engine used.

 

[DCDG]

2021 Jeep GC 3.6 4x4. Owned since new currently with 87k. Used various brands of 0w20 with Valvoline flavors for the last 20k. Mostly 5-6k intervals. Switched to AMSOIL Signature Series 0w30 for this oil change.

I know this isn’t a laboratory test. But this trip we take from Ohio to Florida is one we take every summer for the last 16 years with the same route without deviation. Once there our vehicle sits for the week and we take the FIL’s van when we go places. So it’s as close to a consistent “real world” experience as I can personally get.

Engine: The 3.6 is relatively noisy as is. With the 0w30 it sounds less raspy and smoother. I felt no noticeable drag on the engine.

MPG: The cars computer is relatively accurate. The car has the total trip MPG listed at 24.6. I logged my fill ups and by hand it came out to 24 even. Last year with 0w-20 on the same trip the car had it listed at 25 with by hand calculation it was 24.2. So I guess technically it lost a fraction of MPG’s with 0w30 but in my opinion that could be just in the margin of error.

Oil Temperature: With 0w-20 oil temperatures would top out at 199 degree. Usually sitting at 194 most of the time. I don’t ever remember it hitting 200 on these trips. With 0w30 it sat at 197 most of the trip but would peak at 204.

Oil Pressure: With 0w-20 during idle and cruising it sat at 30 psi and top out at 78 psi under hard acceleration. With 0w30 during idle/cruise it sat at 31-32 psi and top out at 82 psi under hard acceleration.

Oil Usage: During these trips I’d usually “top off” a small negligible amount to bring it back to the top of the full mark. This trip it’s stayed exactly on the same full mark. No top off needed.

With my OCD I researched for months going back and forth on if I should move from a 20 to a 30 weight. With these engines having dry start concerns I landed on 0w30 over a 5w30. Will it all make a difference in engine life? I have no idea, I sure hope so! Thanks for reading.
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It’s doing everything a slightly thicker oil would do. The mpg ain’t nothing to worry about any variable can drop the mileage by a few tenths. 30 wt has slightly more drag thus the higher oil temp and pressure doesn’t flow as fast or shed the heat like the 20 wt the difference is too minuscule to shake a stick at. Since the 20 wt performs well within its operating range the choice is solely preference no science backed data here either one is offering more or less protection.

I’ll just throw out there my brother in law has a 2013 dodge with the 3.6 in South Carolina very hard on the car and lax with maintenance. He gets Walmart oil changes of nothing special the sticker says they use 5W20 the engine may not be quiet as a Swiss watch movt but it runs like a good Japanese knock off.

 

[GW.]

Personally I’ve never seen a measurable mpg difference going up a grade. I certainly have seen differences from fuel, tires, temperature, driving style etc. It’s very hard to pin point with so many variables. Even in fleets it’s fractional at most.

As far as protection there isn’t an official wear study that I’ve read that shows lower viscosity out performing or equaling a higher viscosity in wear. Now whether that impacts your engine during ownership is the real question. But with fuel dilution/shear and severe service I personally like the headroom.

 

[DCDG]

30k worth of data on my Frontier 3.8 shows a loss of 1.5 mpg going up to a 30 grade oil from 20 grade. Same oil brand and series. I just changed tires and loss another mpg. With these fuel prices I will be going back to a 20 grade. I feel like there are millions of miles on a 20 grade oil from different manufactures without engine loss. Now what is interesting is this is city as hwy mileage is the same. For those that don't know I use my truck for work and put close to 400 miles a week with 60% city driving. Lots of stop and go with some idling mixed in.

19 mpg city and 24.3 mpg hwy on 20 grade
17.5 mpg city and 24.3 mpg hwy on 30 grade

1000 miles on new Firestone Destination LE 3 17.5 mpg with 30 grade.

Hopefully it will get better as I drove like a grandpa for last tank and got 17.8 and that was 100 miles on the hwy with cruise set at speed limit.

Many pound the sand with a religious belief and cult like following that a 30 wt will single-handedly out perform modern 20 wt's. Modern full synthetics in a 20 wt are very robust and the differences are too slim for the daily driver. The reason you're seeing slightly better city mileage with the 20 wt is because of its ability to flow at lower temps it's possible both oils aren't getting fully up to operating temperatures and highway the 30 is thinning out at highway temps balancing out the differences. Looks like the 20 wt does a good job staying a 20 perhaps if it were thinning out maybe one would see a few tenths more mpg on the highway.

 

[BobUser]

30k worth of data on my Frontier 3.8 shows a loss of 1.5 mpg going up to a 30 grade oil from 20 grade. Same oil brand and series. I just changed tires and loss another mpg. With these fuel prices I will be going back to a 20 grade. I feel like there are millions of miles on a 20 grade oil from different manufactures without engine loss. Now what is interesting is this is city as hwy mileage is the same. For those that don't know I use my truck for work and put close to 400 miles a week with 60% city driving. Lots of stop and go with some idling mixed in.

19 mpg city and 24.3 mpg hwy on 20 grade
17.5 mpg city and 24.3 mpg hwy on 30 grade

1000 miles on new Firestone Destination LE 3 17.5 mpg with 30 grade.

Hopefully it will get better as I drove like a grandpa for last tank and got 17.8 and that was 100 miles on the hwy with cruise set at speed limit.

Again, nah.

Simply too many variables in city driving ... you are way outside the 0.5-2% expectation ... even if extremely cold wouldn't expect that much difference.

 

[kschachn]

Many pound the sand with a religious belief and cult like following that a 30 wt will single-handedly out perform modern 20 wt's. Modern full synthetics in a 20 wt are very robust and the differences are too slim for the daily driver. The reason you're seeing slightly better city mileage with the 20 wt is because of its ability to flow at lower temps it's possible both oils aren't getting fully up to operating temperatures and highway the 30 is thinning out at highway temps balancing out the differences. Looks like the 20 wt does a good job staying a 20 perhaps if it were thinning out maybe one would see a few tenths more mpg on the highway.

Many pound sand with a religious belief that a 20-grade is somehow superior to a 30-grade. It is, but only for fuel consumption. Not for any other reason. So if that is your one and only criteria then your post makes some sense.

And it's not about flow.

 

[kschachn]

As far as protection there isn’t an official wear study that I’ve read that shows lower viscosity out performing or equaling a higher viscosity in wear. Now whether that impacts your engine during ownership is the real question. But with fuel dilution/shear and severe service I personally like the headroom.

No, the wear studies (posted here multiple times) always show that a higher HT/HS reduces wear. It isn't linear but it is always less wear.

 

[GW.]

No, the wear studies (posted here multiple times) always show that a higher HT/HS reduces wear. It isn't linear but it is always less wear.

Exactly, physics is real.

 

[DCDG]

Many pound sand with a religious belief that a 20-grade is somehow superior to a 30-grade. It is, but only for fuel consumption. Not for any other reason. So if that is your one and only criteria then your post makes some sense.

And it's not about flow.

Not this guy here. Why should I chase something that isn't in existence? My vehicles, friends and family vehicles are doing everything they're supposed to with a 20 wt. If the vehicle calls for something else then that's what it would get. Until then its toes in the sand for this bloke.

 

[cptbarkey]

Same Pentastar engine as OP but a little less fancy with a 2014 Grand Caravan, I went from 5w30 to Delo semi syn 15w40 in my ranch Grand Caravan.

3.3k miles later, absolutely no change in MPG or butt dyno at all.

Startup rattle is lower, but I didnt switch for any reason except my whims and years of reading this forum that things would be ok.

 

[Pablo]

I only notice a very slight seasonal MPG change in our vehicles over the years. I mean even my Toy 3.5 Tacoma running SAE 40 range, v SAE 20 range, no MPG difference. But summer, maybe an indicated 0.5 mpg gain over winter, due mostly to fuel and ALL fluids being relatively more viscous.

 

[kschachn]

Exactly, physics is real.

For most people.

 

[Indestro]

Many pound the sand with a religious belief and cult like following that a 30 wt will single-handedly out perform modern 20 wt's. Modern full synthetics in a 20 wt are very robust and the differences are too slim for the daily driver. The reason you're seeing slightly better city mileage with the 20 wt is because of its ability to flow at lower temps it's possible both oils aren't getting fully up to operating temperatures and highway the 30 is thinning out at highway temps balancing out the differences. Looks like the 20 wt does a good job staying a 20 perhaps if it were thinning out maybe one would see a few tenths more mpg on the highway.

Not this guy here. Why should I chase something that isn't in existence? My vehicles, friends and family vehicles are doing everything they're supposed to with a 20 wt. If the vehicle calls for something else then that's what it would get. Until then its toes in the sand for this bloke.

These are good points. However, on the other hand, we have all seen various vehicle manufacturers change their engine oil recommendations *after* their vehicle is on the market and engine problems are reported. From what I recall, manufacturers always go from their original recommendation to a *higher* viscosity recommendation. I have never seen them change to recommending a lower viscosity oil.

If anyone has examples of manufacturers changing their recommendations to a lower viscosity engine, please let me know.

Indestro

 

[BobUser]

Not this guy here. Why should I chase something that isn't in existence? My vehicles, friends and family vehicles are doing everything they're supposed to with a 20 wt. If the vehicle calls for something else then that's what it would get. Until then its toes in the sand for this bloke.

Cool - you are inaccurate, but it’s OK cause it’s your vehicle and your decision.

 

[DCDG]

Cool - you are inaccurate, but it’s OK cause it’s your vehicle and your decision.

This is your opinion.

 

[tah8436]

Heck, even a headwind vs tailwind can affect MPG on the same road trip by +/- 10%. I think trying to spot the MPG differences yourself after changing oil grades is a fool’s errand.

IMO, better to instead use the known ~1% loss figure to rationalize if it’s worth the slight extra gas cost to bump up oil grade.