Synthetic Oil - Do you use it in Cummins Engine?

[Kidoo]

Anyone did switched to synthetic oil? I wonder if there is any bad effect to switching to synthetic oil on a 2003 Cummins. My engine book says we can do it.

I would like to put 10W40 year long. It should be easier to start in colder temps and should last a year per oil change.

Anyone using 5w40 synth. year long? This is what I use in my Ford Diesel.

[Jarlaxle]

jcthorne wrote:

mci7 wrote:
There are zero reasons to use the synthetic oils,
Like many sales ads, it is just a feel good thing, Having only used the Shell 15W-40 in all my Diesel engines, the vehicles wear out before the engines.
Do what makes you feel better. !
Dave M

If your trucks are wearing out before the engines, you need to take better care of your trucks.

I saw a 7.3 PSD in an F-550 ramp truck wind up 930,000+ miles...and it NEVER got anything but whatever 15W-40 the boss got a good price on! Original turbo, even had 3 original injectors!

Around here, they don't wear out...they RUST! (Or, like that F-550, they get wrecked.)

[Jarlaxle]

mci7 wrote:
There are zero reasons to use the synthetic oils,
Like many sales ads, it is just a feel good thing, Having only used the Shell 15W-40 in all my Diesel engines, the vehicles wear out before the engines.
Do what makes you feel better. !
Dave M

That! Synthetics are better...but in almost all cases, it just doesn't matter, because regular oil is good enough.

[Kidoo]

From what I read, I see a few advantages for synth.
Better cold starts
Better lube for the turbo
Quicker flow of oil and quicker lube for cold or cool temps
Probably better for keeping engine cleaner

[wildmanbaker]

jcthorne wrote:

mci7 wrote:
There are zero reasons to use the synthetic oils,
Like many sales ads, it is just a feel good thing, Having only used the Shell 15W-40 in all my Diesel engines, the vehicles wear out before the engines.
Do what makes you feel better. !
Dave M

If your trucks are wearing out before the engines, you need to take better care of your trucks.

He's right, the trucks do wear out before the engines. They get beat to death on the highways, and work 10 to 16 hours a day. Take a ride in a rig that has a million miles on it and see if you can hear.

[Ivylog]

If you are going to change once a year reguardless of miles NO.

[jcthorne]

mci7 wrote:
There are zero reasons to use the synthetic oils,
Like many sales ads, it is just a feel good thing, Having only used the Shell 15W-40 in all my Diesel engines, the vehicles wear out before the engines.
Do what makes you feel better. !
Dave M

If your trucks are wearing out before the engines, you need to take better care of your trucks.

[P_Kennedy]

mci7 is right in that it is your choice but to think that lubricating oils are the same chemical make up that was available as little as 10 years ago is mis-information. Even the dino oils are enhanced with detergents and friction additives. The base stock is different due to refining methods and the government requirements. If the only advantage is a cold start on a diesel without preheat you are chasing the wrong goal, 5000 mile oil changes are a personal choice. Trucking companies average 12-15000 mile oil changes working the engines hard all day everyday. The video was part of a Mobil 1 advertisement but what he was showing you is a fact, all you have to do is ask a diesel mechanic about coking oil on turbo bearings. Series 4 synthetics are chemically engineered oil molecules which makes a cleaner and more stable oil molecule which flows at lower temperatures and burns off at higher temperatures. Zero advantages I will disagree, personal choice definitely. Cummins compatible they agree within break in specs. I know that getting my diesel started is minor after living in the cold north for 50+ years, seeing oil pressure within 4-5 seconds at -20 or lower is saving my bottom end and valve train. Worrying about it in a motorhome not as critical because they usually are not used in those temps. However there have been several posts on here about costly engine failures and some were heat related which synthetic oils are better at handling. Take your oil sample to a lab for testing and see if they agree all oil is the same and what's in yours. I also like LED technology too makes me feel good.

[PatStab]

Our motorhome is old, a 1992 American Eagle we thought about changing to synthetic but changed our minds. The manual says change oil every 5000 miles so my husband stuck with the 15 40 rotella. Since we are changing it frequently enough we don't think it will make a difference.

We keep it in a garage here in Indiana. Last winter when I was going to leave on a trip and it was in the 20's and 30's I put a heater near the engine for a day and the night before I left. The engine kicked off ok. I have an engine heater to plug in but have never used it. I assume it works, may try it this winter before we leave to see if it works. On the generator we have a heater switch to hold for 30 seconds and it starts right up. So the oil we are using is fine.

Also as old as it is we did not change to synthetic for the transmission either, if it were newer we would have.

[mci7]

There are zero reasons to use the synthetic oils,
Like many sales ads, it is just a feel good thing, Having only used the Shell 15W-40 in all my Diesel engines, the vehicles wear out before the engines.
Do what makes you feel better. !
Dave M

[P_Kennedy]

Excellent video which completely explains why shutting down a hot turbocharged engine "cokes" the oil onto the bearing shaft and bearing. Pyrometer readings are what tells you when the turbo is red hot, water temp tells you when the head is being cooled adequately. Dino oil starts to burn or coke at a lower temperature than synthetic oil. Only Mobil 1, Royal Purple, Amsoil Premium oils are true PAO Series 4 synthetics the others are series 3 blends which are good but "dino" based. Like I said dino will do the job but synthetic does it better but costs more.

[Kidoo]

06Fargo wrote:
Mobil 1 video on synthetic oil in turbocharged engines

It does the same on my Ford Diesel 6.0. The problem on this engine is with dirty injector which operates with oil. If you use normal oil, it will get sticky. If you use T6 Rotella synth., the injectors stays cleaner and will last much longer.

[noteven]

Mobil 1 video on synthetic oil in turbocharged engines

[Kidoo]

My son has a cummins in a Dodge. He switched to synthetic at around 100000 miles and did not have any problem. The engine does start much better in the minus 30 temps.

I am also a bit afraid of seals and gaskets, I have no leak at all right now.

[P_Kennedy]

$30-45k engine, $300-500 oil change once a year, superior product in every way, nope no advantage. Motorhome owners are notorious for quick start ups and idle 10 minutes then work the******out of a cold engine which is pushing a fully loaded unit as per the many claims here. Then no matter how hot or cold they need to be running with the light vehicles up the hills/traffic and most don't watch the water temp guage and have no pyrometer to see how warm the top end is getting. Nope no advantage. Yup the other stuff works and does a good job but oil sampling and engineered oils give you the technical truth of the engines condition internally. Yes you can use synthetic oil if the engine is past initial break in and not leaking a bunch of oil from the gaskets and seals.