I currently run Amsoil 15W-40 oil in my engine, as I have for the past 30,000 miles. I know that a benefit of running synthetic is extended drain intervals, however I have always changed my oil every 7,500 - 10,000 and done oil analysis. I also run Fleetguard filters. In an effort to save a little money, I am considering switching back to Rotella. I was wandering if it would be safe to switch from synthetic back to dino, and if there are any special steps I would need to take in order to do so. Any advice is greatly appreciated!

 

I did and it stopped using oil. Engine still runs strong as ever.

 

I dont see a problem with it. Does your oil analysis come saying you need to change it or do you just go ahead and change just to be safe. You shouldnt have to do anything to change back to dyno.

 

The oil analysis always comes back saying the oil is suitable for continued use. I just change it to be safe.

 

If your changing your even though the oil report tells you the oil is still good your wasting oil and your money.

 

I've ran the Amsoil 15W-40 for just over 60k with changing the oil every 20k. Sent in an oil analysis all 3 times....always came back that oil was good to go for another 5k then do another oil analysis. I just always changed it at 20k...

No issues at all. Doesn't burn a drop of oil with 20k intervals. Motor seems to run "smoother" with the Amsoil than it did with the Rotella...could just be wishful thinking though.

 

you trusted the claimed and substantiated benefits of the synthetic oil disregarding the added cost initially but refuse to trust the technology to analyze it and reap the rewards of that product.... Hmmmm.

Why don't you go rethink your decision to ignore technology and trust what they tell you with a 20,000$ piece of test equipment. Stay with the synthetics and go as long as they say to. It depends on so many variables as to when the right time is to change the oil. Remember, oil doesn't wear out, it gets dirty. If you can't clean it sufficiently to continue the job it was designed to do, then you have to throw it out and put some new clean stuff in.

 

It's not the fact that I "ignore technology and not trust what they tell me", it's the fact that I have always gone by what the manufacturer of the engine has said to do. It clearly states in the owner's manual that there are two different service intervals to go by, one for normal service and one for extreme service. It also states in there "the same oil change interval is to be followed for synthetic oil as for petroleum based oil. Also, synthetic oil must meet the same performance specifications as petroleum oil." With Cummins being the company that designed, built, and tested the engine, I feel that their technology and recommendations should be trusted. It is one thing if a dealership or quick lube tells you to change your oil at 7,500 or 15,000 miles, but it is another when Cummins says to. Another thing I am not completely comfortable with is that Amsoil 15w-40 is not API certified. Amsoil states"recommended for all diesel engines or gasoline engines requiring any of the listed specifications" and API CI-4+/CF/CF-2/SL are listed, but no where on the bottle will you find an API certification seal. I have ran Amsoil for years in various applications, and I know that they make some superior products. I respect everyone's decision to put in their trucks what they choose. In my specific application, I would like to switch back to an API certified oil and change it at the intervals that Cummins says to. Therefore that is why I turned to this forum to seek advice from experienced CTD owners on whether or not I could easily transition from synthetic back to dino oil.

 

OK, cool. You've answered any questions I guess then. Dont throw money at having it analyzed... and don't waste money on synthetic oils, go by the mfg suggested change interval and use "dino oil" or in my opinion, prehistoric vegatative oil- since there was a lot more vegetation than dinos back then... and be done with the matter.

No big deal... didnt mean to ***** you off. Just my opinion. Take it or leave it... all the same to me. You have a good oil change ethic there, stick to it and I dont see you having any oil related problems with your CTD.

 

No offense taken, thats what these forums are designed for, so one can get advice/opinions from many others. Just wanted to make sure that switching oil types will not cause me to have any type of catostrophic engine failure.

 

Did any of you notice that the engine noise when ideling is a little louder with synthetic? or is it because I used Mobil one synthetic for turbo diesels 5w-40?
I have been using the Rotella 15w-40, but since its fall I thought I would try the synthetic. for winter this year. Last year I used the 15w40 in winter but I didn't start the truck on the colder days, maybe a few times in the 20's here in virginia. It seemed ok. I don't drive it every day
First time I have tried the Mobile one

 

One reason Cummins does not show a longer oil drain interval when using synthetic oil is because most all of the oil on the shelf in the stores that are labeled synthetic are just highly refined group III crude oil and not 100% man made group IV or group V synthetic oil like Redline, Amsoil or Royal Purple make.

 

I didn't notice my engine being a little louder while ideling while using synthetic, actually I'd say it was a little quiter. I have never used 5w-40 though, I have always used 15w-40 so that could be the difference. I noticed you are in VA, I am in SWVA as well down near Bristol.

 

Its like the injectors are louder or something. But I can tell a definite difference after driving in an hour, when sitting in the driveway. I used Fully synthetic Mobil 1 Turbo Diesel Truck 5W-40. It says with SuperSyn which is engineered for hard-working diesel engines.
I don't think mine works that hard though. First time using synthetic, same Fleetguard oil filter. I don't know, we drove it to WVA camping weekend before last and it ran perfect, oil pressure normal, but it was a little louder with that cummins truck noise, you know when you start it.. Which is fine. I like it, I just noticed it.

Oilbuner04: thats nice area down there. we visit Abingdon often and E&H.