Oil considerations: 10w40 vs 10w30

[bohuggabee]

Sadly, castrol doesnt sell the high mileage gtx in 5w40. What i really want.... Was really hoping to try it. Used gtx 10w30 for a decade and love it. Very predictable oil and my jeep runs phenomenal on it ever since the switch. My main concern, i have 167,000 miles on my 99 4.0., now driving Very steep roads daily and i just want extra protection in my low end torque band. But castrol gtx vs edge, a high viscosity, and weight. You will just get a bit more oil before it replaces , and itll stay on the valves and springs longer. Reducing that low end cackle when i have to take sharp turns and torque up these ridiculous grades. My real question, is how a synthetic vs a blend could benefit in the long run. Fully synthetics are purer and stable and have better heat tolerance. The gtx would in theory gum up a bit, heat soak, add oil pressure over time, requiring more frequent oil changes. More burning solvents over time. I havent had any seal issues like others mention with gtx. However im wondering if that could start happening with a heavier blend. Building a corrosive carbon layer or transversely benefit . I use a high rated k&n filter. Its fantastic for smoothness.

 

[KennethS]

I havent had any seal issues like others mention with gtx. However im wondering if that could start happening with a heavier blend.

The thicker oil would be less likely to leak than a thinner oil.

 

[JEEPSTEVENANAIMO]

i personally use mercedes synthetic 5w40 229.5 quality.

 

[tworley]

Plain old high mileage 10W-30 oil. Whatever is available on the shelf. Don't overthink it.

 

[bohuggabee]

Plain old high mileage 10W-30 oil. Whatever is available on the shelf. Don't overthink it.

These roads are steep. And im frugal. So in the long run. Im going to try 10w-40 full synthetic for now. My understanding now is that my objective is more oil on my springs and valves and cams. Smoother torque up a high incline at lower rpm. Less carbon strings over time so less potential for resistant sludge. But idk everything about how the chemicals work. Its not like they specifically target carbon. Looking around the engine for it. Its there either way... ive used a blend for many years. I feel comfortable here trying full synthetic.

And i considered power loss. My jeep is stripped almost. Lightened as much as possible. So the extra viscosity and weight ratio wont matter.

But too. I was wondering about the fuel and oil mixture. Carbon strings in the combustion vs the full synthetic and what that does. I doubt itll be too much of an issue, however id love it anyone could advance my knowledge on it.

 

[KennethS]

I have used full synthetic in mine since 2002 with absolutely no issues, so I have nothing negative to say about it. I changed to the high-mileage version a few years ago and that stopped a rear main seal drip.

 

[basedbb69]

I use rotella t5 15-40. It's a great oil for any flat tappet motor.

 

[John Cooper]

Aimsoil is what you need might even get 50 MPG using it....... .

 

[Cooper Smith]

Aimsoil is what you need might even get 50 MPG using it....... .

Only downhill though. With camber on a vehicle without adjustable camber. Dare I say, not on a humid day? (seriously wtf was the rationale he used in that thread???)

I used to always say "RTFM" to posts like these on Facebook until GM's 6.2's got recalled for connecting rods, and the "solution" is a heavier oil. I'm not an engineer, but I work with them. They make bad judgement calls frequently. Like others have said, I may start putting Rotella 15w40 in my TBI 350. I only drive it in the summer anyways. All the friendly dinosaurs for a flat tappet cam.

@bohuggabee, I vote 15w40 too, assuming this isn't another troll post... vehicles like these aren't that delicate. Oil is oil, idk why you're getting in depth with drag coefficients or whatever, it's not that deep. You can run Costco oil in these and be fine, and buying oil and bulk probably saves you more money than overthinking the drag and fuel economy part of the equation. It's not gonna run noticeably smoother.

 

[John Cooper]

@bohuggabee, I vote 15w40 too, assuming this isn't another troll post...

Well that's a given......... sad thing is, he isn't even a good Trolll

 

[Cooper Smith]

Well that's a given......... sad thing is, he isn't even a good Trolll

A good troll would get angry reactions that haven't figured out that they're being trolled.

A bad troll gets called out and keeps going. I really hope this isn't the "keep going" part. That or he is overthinking vehicles more than I've ever seen.

 

[KennethS]

buying oil and bulk probably saves you more money than overthinking the drag and fuel economy part of the equation.

Wal Mart has Mobil 1 full synthetic 5 quart jug for $26.

 

[Obi-Wan]

Have you considered a more eco friendly option? Tom and Ray promote it exclusively.

 

[bohuggabee]

I have used full synthetic in mine since 2002 with absolutely no issues, so I have nothing negative to say about it. I changed to the high-mileage version a few years ago and that stopped a rear main seal drip.

Thats since 2002. As far as i know it was ran with typical oil for 117,000 miles. It eventually was gumming up sensors and the throttle body... after i got it and drove 10,000. So i concluded to switch to the blend and slowly reduce all that over time. No problems since 127,000 except mechanical stuff. But i figure now its so long. I can switch to a full synthetic without hassle.

Ive never noticed an oil leak, just burns it from not starting right away.

When i changed the starter. The fly wheel was very clean too. Valves all look much cleaner and the intake manifold too. As opposed to when i got it and it was just mucky inside everything. Even the oil pressure sensor was oozing junk and its fine since. Took a long time for it to finally all clean up.

 

[bohuggabee]

Wal Mart has Mobil 1 full synthetic 5 quart jug for $26.

Can we trust walmart oil? Everything they sell is typically degraded in quality some how. Can castrol really express that their oils sold from walmart much cheaper are still the good ole business model and quality or have they been reducing quality for their profit ?

 

[Obi-Wan]

Buy A jug of Rotella 15w-40 and be done with this nonsense. Your thought process is a perfect example of analysis paralysis.

 

[bohuggabee]

Buy A jug of Rotella 15w-40 and be done with this nonsence. Your thought process is a perfect example of analysis paralysis.

Go away... if you havent noticed. Im ignoring all the useless crap you say for attention. Im actually talking cars. Get it?! Idc what you say anymore.

 

[bohuggabee]

I use rotella t5 15-40. It's a great oil for any flat tappet motor.

Idk if you are serious but i do mention weight issues because i live where temperature can be unpredictable. 10 weight is fine for start up till negative temps. Had to buy a special battery just for the times i want to go somewhere in minus 10... weight doesnt mean much to me. Its the viscosity that im analyzing. And besides. I already have it all figured out. When increasing viscosity switch to full synthetic. Otherwise no benefit from the same weight and viscosity of the blend. The hydro carbons wont be a problem.. carbon strings break in odd ways. As the hydrogen frees and the length of carbons fracture. The expansion of the chamber is varying that pressure and heat over time. The hydro carbons and physics back then werent really a direct science. It was a lower tolerance engine specifically for this reason. I can get the benefits of the flow rate and viscosity on my timing without worrying about the slow build up of carbon bonds. That intolerance engines...

 

[Apparition]

Can we trust walmart oil? Everything they sell is typically degraded in quality some how. Can castrol really express that their oils sold from walmart much cheaper are still the good ole business model and quality or have they been reducing quality for their profit ?

 

[bohuggabee]

Anyone wanting to talk oil instead of trolling... 5w-30 and 5w-40 and 10w-30 and 10w-40 all divide into the volume and circumference of your piston and chamber. You can incorporate compression and even thermodynamic radiation. But thats gonna be advanced for people that think wal mart isnt ripping you off... what is the viscosity ratio of 30 vs 40? Is it 10% more viscous? Or 1/3 more viscous? 100 viscosity is a solid. 0 viscosity is water or should technically be a super fluid...and no resistance to flow. There are no room temperature super fluids. No idea what they have 0w oil... if the tolerance of my engine changes a .001-.0001. Im loosing by compression ratio of fuel mixture how much gas outside of the piston? Can anyone guess? Didnt think so! I could explain it for you if you werent all ass holes trolling me. I just am calculating the potential benefits of a fraction of viscosity over the course of thousands of miles of driving to have a subtly smoother torque band.

Idk bubba. I just know i got up that hill. Mean while. My jeep is going to out live me and i dont need a mechanic.