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Any advantages going to a synthetic oil? Reading about it says improved power better fuel mileage? Is it safe going from Rotella 15w40 conventional oil to synthetic??
 

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Simply put.... For most folks Synthetic cost 2x much, lasts 2x as long.

End game is a push.

It boils down to how often you want to get under the truck....
 

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I run synthetic Amsoil in mine, engine, trans, rear diff. As far as improved mileage, more power, etc... I've not seen or felt any. I've got a 99 Cummins that's been modded pretty much from day one. 165,000 on it and I decided to pull the cab to take care of some of the body cancer and pull the engine to fix a couple things and squeeze some more power out of it. It's got a fueling box, injectors, compound twins, fireringed head, etc... and was laying down 600hp for a long time. I wasnt easy on it either, it was my daily driver, towing truck and fun truck sled pulling. When I tore it down I found the block cracked, broken pistons, cracked head, etc.. only thing that was good was the crank and rods. I got new pistons and sent the entire rotating assembly out to have balanced. The shop said they couldnt believe the crank and rod journals were so nice yet, all they did was polish them and I can still use stock bearings. They asked what oil I've been using in it. That being said, synthetics are better as far as wear protection, long term, but if you're looking for mileage and power increases, save your money.
 

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All I run is Rotella 5w40 T6. I run it all year round. Great price and good protection. You will have no issues switching to it but one thing to note. If you have any slight oil leak issues on your engine or oil cooler switching to the T6 will likely cause more of a leak to appear. The synthetic molecules are smaller and more uniform. Great for heat transfer (especially for the turbo) but makes small leaks bigger. Dean
 

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If you have any slight oil leak issues on your engine or oil cooler switching to the T6 will likely cause more of a leak to appear. The synthetic molecules are smaller
Is this a real post? "Smaller" ?? The Amsoil bypass deal filters down to 2 microns.

2 microns equals 0.002 mm. Two thousands of a millimeter.

Dino and synthetic oil flows through these just fine so a molecule of dino oil must be FAR smaller than 2 microns.

And you think that wont leak, but a synthetic oil will?
 

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Is this a real post? "Smaller" ?? The Amsoil bypass deal filters down to 2 microns.

2 microns equals 0.002 mm. Two thousands of a millimeter.

Dino and synthetic oil flows through these just fine so a molecule of dino oil must be FAR smaller than 2 microns.

And you think that wont leak, but a synthetic oil will?
What does a filter micron rating have to do with this? Do a bit of research. Synthetic oil will not cause leaks but it will cause small leaks to leak a bit more. Dean
 

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Synthetic Oil

Simply put.... For most folks Synthetic cost 2x much, lasts 2x as long.

End game is a push.

It boils down to how often you want to get under the truck....
I buy Rotella T6 full synthetic oil for a few dollars more per gallon than T5 or T4 oil and I shop around and never pay more than $20 per gal and on sale $16 per gallon actually cheaper than many places out there just look around. I change any oil about 5000 miles and over the years have been sold on synthetics due to their better lubricating properties and most have more detergents and have kept my engines cleaner over the years. In the mid 90s I had an S10 with a 2.8 that I used Mobil 1 from the first oil change where at 323000 miles I had to replace the black RTV on the rear intake and the rockers were clean with no sludge. A valve started sticking around 460000 miles so I got rid of it.
 

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I’ve been happy with Rotella T5 15-40. If you can get T6 for just a bit more, go ahead. I change oil often enough (due to lots of dusty/dirty conditions, amount of start/stop cycles, etc.) that I go with T5, as T6 is always more $$$ out here

Hope this helps.
Ely
 

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T6 the cost difference especially if you shop around for sales is not much when your servicing a $50K piece of equipment.

But the T5 and T4 are quality products. none of them would hurt my feelings using regularly

my .02 good luck
 

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Any advantages going to a synthetic oil? Reading about it says improved power better fuel mileage? Is it safe going from Rotella 15w40 conventional oil to synthetic??

There is very little different in terms of performance. The synthetic lasts a little longer, but realistically unless your removing soot from the oil, your change interval will be before either oil package is depleted. Synthetic has better cold start characteristics so in cold climates its more free flowing. Thats about it. Its safe to go from one to the other back to the first and so on if you like. Some people run synthetic in the winter and conventional in the summer. Basically run whatever makes you happy. For me, thats dino oil every 4K ish.
 

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There is very little different in terms of performance. The synthetic lasts a little longer, but realistically unless your removing soot from the oil, your change interval will be before either oil package is depleted. Synthetic has better cold start characteristics so in cold climates its more free flowing. Thats about it. Its safe to go from one to the other back to the first and so on if you like. Some people run synthetic in the winter and conventional in the summer. Basically run whatever makes you happy. For me, thats dino oil every 4K ish.
Agree and like Bob said, if you're going to go twice as long (15k-20k) between changes, go synthetic. After all the research I did before making my decision, I decided to go with regular 15w-40 and change it every 5k or so. Filtration is just as or maybe more important than the oil you use. Use good efficiency filters and change them and the oil often!

Good Luck in your decision!
 

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I am going to start off by saying i am not an oil expert. I run Amsoil 5W-40 and have been in my duramax since about 1000 miles. The main reason i went to full synthetic is to get the 5W-40 rating as i live in a climate where one day it could be 30 above and the next it could be -10 and I only put enough miles on my pickup to change oil once per year. The ability to have an oil that allows for better cold starts is why i went the synthetic route. I did do an experiment last year and put Amsoil 15W-40 in just to see if i could tell a noticeable difference in cold starts as well as to see if these two maintained similar oil pressure at operating temp. I did find there was a pretty considerable difference in the cranking speed but the pressure at operating temp was the same, as to be expected.

I guess IMO if you live in a climate where you have both cold and hot extremes i prefer to run a synthetic for the 5W-40 rating, or if you want to extend you oil service intervals go synthetic.
 

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I am going to start off by saying i am not an oil expert. I run Amsoil 5W-40 and have been in my duramax since about 1000 miles. The main reason i went to full synthetic is to get the 5W-40 rating as i live in a climate where one day it could be 30 above and the next it could be -10 and I only put enough miles on my pickup to change oil once per year. The ability to have an oil that allows for better cold starts is why i went the synthetic route. I did do an experiment last year and put Amsoil 15W-40 in just to see if i could tell a noticeable difference in cold starts as well as to see if these two maintained similar oil pressure at operating temp. I did find there was a pretty considerable difference in the cranking speed but the pressure at operating temp was the same, as to be expected.

I guess IMO if you live in a climate where you have both cold and hot extremes i prefer to run a synthetic for the 5W-40 rating, or if you want to extend you oil service intervals go synthetic.
I just switched to 15w-40 Amsoil AME in my powerstroke and will be switching the Duramax on its next change. I noticed the powerstroke ran much more quiet with the Amsoil.
 

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$120 for 4 Gallons is $30 a gallon, not a bad price

Rebate brings it down to $20.25 a gallon

Unbeatable.......
 

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Simply put, if you use synthetic, then stick to their recommended oil change intervals. Otherwise, you are wasting money if you change your oil sooner as with the recommendations of conventional oil. Synthetics give you the ability to extend oil change time frames. Both conventional and synthetic oils today provide good protection. One simply can go longer oil change intervals.
 

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Tests clearly show synthetic oil to be far superior to mineral based. One big advantage is that you can get 5w-40 syn oil and only 15w-40 mineral so in cold weather and cold starts you will see a big difference. Oils are not developed by oil companies, but by speciality companies that sell additive packages to Shell for mfg of their oil. I was visiting the largest of these several years back and they have extensive dyno cells, chem labs, etc and do a lot of back to back testing. So I asked which is the best diesel oil, he went and asked one of the gurus and Shell Rotella was the answer by far. I may be dumb but not stupid I just use Rotella T6 5w-40 now.
 
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