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Mobil Delvac 1300 Super 15W40 CK4/SN

20K views 9 replies 4 participants last post by  rdg 
#1 ·
I understand the factory oil fill in the Duramax is still Mobil Delvac 1300 Super 15W40. Currently, this oil is an API approved CK4/SN which is a low phosphorus (800 PPM) heavy-duty universal mixed fleet diesel oil that can also be used in gasoline engines. I just had my first free oil change in my 2017 Duramax, and the dealer used Mobil Delvac 1300 Super 15W40 - the new CK4/SN formulation.

The previous generation of Delvac CJ4 HDEO performed well in my 04 Duramax, and I used Delvac successfully for many years. However, I have not seen any used oil analyses (UOAs) on the new CK4/ SN Delvac 1300 Super 15W40. I am curious how the current CK4/SN formulation is performing in the Duramax, especially considering the lower level of phosphorus.

Any feedback on the performance of Mobil Delvac 1300 Super 15W40 CK4/SN would be appreciated.
 
#2 ·
First, I'm not an oil geek. There are not that many UOAs posted on the L5P. Currently, there is just one on BITOG running Delvac 1 ESP in 5W-40 which carries a CK-4 certification. Wear rates were excellent. I have 2,000 miles to go on my first free change (Delvac 1300 Super). I'll sample and post the report on BITOG. I think the more important question is how similar is the L5P to previous generations re wear rates. GM says it shares displacement and name and little else. Gale Banks said pretty much the same in his videos. If the wear rates track previous generations then we are golden. These engines just don't care as long as the oil is the proper grade and certification.
 
#3 ·
Your point is taken on how similar the new L5P Duramax will be on HDEOs. My 04 D-max wear rates were low using the previous generations Delvac 1300 Super.

We are actually looking at two (2) input variables now: the L5P and low phosphorus CK4/SN Delvac. To date, there has not been UOA postings for either. In my opinion, it's important to establish a data base of UOAs on both the L5P and Mobil Delvac 1300 Super 15W40. I, too, will be posting UOAs on BITOG for my next OCI.

I appreciate the response.
 
#4 ·
Hello ! I am new to the forum and have a question about oil. I have a 2002 Duramax 2500 and have always used synthetic oil in my 2002 2500 GMC, usually Mobile 1 and have had good luck so far. Occasionally I used Rotilla when Mobile one was not available. I just had my oil changed and specified I wanted SYNTHETIC OIL. Usually I buy my own synthetic oil and take it to the dealer. This time I decided to let the dealer use their synthetic GM oil. I was told they have GM synthetic and had my oil changed. MY QUESTION IS : Is GM oil PN 88862612 SYNTHETIC OIL ? I was told also that it was Mobil 1 Delvac . I really hope someone can help with my question. Thank you. I have always used synthetic in all my cars, vans ,truck and lawn equipment and have been VERY satisfied. Thanks for any help ! Duke
 
#5 ·
MY QUESTION IS : Is GM oil PN 88862612 SYNTHETIC OIL ? I was told also that it was Mobil 1 Delvac .
https://www.gmpartsgiant.com/parts/gm-oil-88862612.html

I am not an oil expert by any means but have read lots of oil posts. I googled that part number and it appears to be a 15W40. See link above. In most cases this would mean that it is not fully synthetic. It may possibly a synthetic blend. That said, I think it will probably do a good job for your engine.
 
#7 ·
Duke13 - I actually have just 5500 miles on my Duramax. Most of my diesel experience is driving VW TDIs. When I am not pulling a trailer, I am getting about 18 - 19 mpg average on the Duramax with 70% highway and 30 % stop and go. Looks like I would get around 21 to a maximum of 23 mpg on a highway only trip .
 
#8 · (Edited)
My google-fu on that part number says it's bulk Mobil Delvac 1300 which would be a full syn.

There is a Duramax owner on BITOG (dnewton3) whose day job is statistical analysis. He downloaded over 500 Duramax UOAs from Blackstone and his conclusion is at normal change intervals the Duramax doesn't care what oil is in it. They turn consistently low wear numbers regardless of brand. His mantra is that as long as the oil is in the proper grade and carries the correct API certification you are wasting money on short OCIs with expensive oil. That said, I've got 2.5 gallons of Schaeffer's for my next change. Old habits are hard to break. After that I'll run T5 which is a blend and then SuperTech which is a full syn and now certified CK-4/SN and see what my UOAs show.
 
#9 ·
Hi Guys, Thanks for the input. I found out some interesting info. gm pn 88862612 is Mobile delvac but is the normal diesel oil used by most Gm Dealers. Mobile 1 delvac is a full synthetic, viscosity of this oil is 5w-40. Viscosity of mobil delvac is either 15w-40 or 10w-40. So if you are expecting a full synthetic be sure it is mobile 1. I have a gallon of Mobile 1 Synthetic for diesels and the viscosity is 5w-40. I have been using Mobile in my 2002 GMC diesel since new and hate to change. I know the synthetic oil keeps the motor clean. I had a 1990 Liumina that I used Mobile 1 the entire time and got 214,000 miles. You could look in the engine via the oil fill cap and it was as clean as new. I have A 1991 gmc VAN AND HAVE ALWAYS USED Mobile 1, A 2017 Chevy Impala AND USE mOBILE 1 AND ALL MY LAWN TRACTORS AND ANYTHING I HAVE THAT USES OIL GETS mOBILE 1. Thanks for your input. Duke
 
#10 ·
Well, I used my last free dealer oil change a while back on my 2017 3500HD Dmax. The dealer changed the oil and filled with Mobil Delvac 1300 Super 15W40 CK4, and it's approaching time for my next oil change. I am not sure which oil I will use. Mobil Delvac 1300 Super 15W40 is the factory fill in the Dmax. I understand that Mobil is advertising that Mobil Delvac 1300 Super 15W40 CK4 is now a synthetic blend. However, the rub is that there are no regulations governing the minimum amount of synthetic base stock used in synthetic blended motor oil.

Since the L5P has been out a couple of years, I am curious if there is still a following for Mobil Delvac 1300 Super 15W40 CK4 in the Dmax. Or, feedback on any other HDEO brands would be helpful.
 
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