11 quarts to fill my truck after oil change

64BAwagon · May 20

I recently changed the oil in my new 2025 L5P Duramax along with a new PF63 filter. It took 11 qts to get the dipstick to read at the top of the full mark. I thought this was a 10 qt engine ? Could it be that the pan was revised for a more thorough drain ? Banks has been making a big deal out of the pan not draining completely.

Anyone else notice this ?

Chuck FB · May 20

1 hour ago, 64BAwagon said:

I recently changed the oil in my new 2025 L5P Duramax along with a new PF63 filter. It took 11 qts to get the dipstick to read at the top of the full mark. I thought this was a 10 qt engine ? Could it be that the pan was revised for a more thorough drain ? Banks has been making a big deal out of the pan not draining completely.

Anyone else notice this ?

You've got me curious, while I don't have that answer I was wondering if you think there is something reshaped in the area of the drain hole bung to lower that area from the rest of the sump area. They wouldn't have been able to get rid of the thread length of that weldnut style bung unless they redesigned the bung to stick below the surface of the pan which certainly some engine manufacturers do to avoid creating the stand pipe effect. I brought up the video from Banks where they put on the clear pan they made to give a visual and of note, they are showing a certain amount of oil that is sitting inside the pickup tube that ran out once the pan was lowered so the pickup was no longer in that oil pool at the bottom of the pan. Is it possible that you left yours drain longer and the pickup tube was allowed to drain out completely. Or the other thought, did you drive the front of your truck up on ramps or jack up the front as that could have had enough of an effect to not only drain the pickup tube but more of the oil normally left in the pan if the truck was left in a level condition throughout the oil change procedure. Banks claimed there was an additional quart of oil they got out of the engine by dropping the pan, what was in the pan along with what came out of the pickup tube that then added up to 11 quarts.

Edited May 20 by Chuck FB

64BAwagon · May 21

It was on a slight incline but not nearly enough to account for extra. I always let my vehicles drain since I am in no hurry. I just thought it was coincidental to the Banks rants. Not that he doesnt have a point but he surely has heard of the 7.3L Ford/International OR Internationals DT466, those things retained some oil in the high pressure system for sure. The DT466 dipstick never looked like it had clean oil on it even 15 minutes after changing it.

I am not going to lose any sleep over it for sure. I can still recall the days when it wasnt uncommon to do a half oil change with filter on a heavy truck. I believe it was referred to as "sweetening" the existing oil to save the cost of a full change.

Edited May 21 by 64BAwagon

Chuck FB · May 21

32 minutes ago, 64BAwagon said:

It was on a slight incline but not nearly enough to account for extra. I always let my vehicles drain since I am in no hurry. I just thought it was coincidental to the Banks rants. Not that he doesnt have a point but he surely has heard of the 7.3L Ford/International of Internationals DT466, those things retained some oil in the high pressure system for sure. The DT466 dipstick never looked like it had clean oil on it even 15 minutes after changing it.

I am not going to lose any sleep over it for sure. I can still recall the days when it wasnt uncommon to do a half oil change with filter on a heavy truck. I believe it was referred to as "sweetening" the existing oil to save the cost of a full change.

Banks in my thinking is pushing a bit too hard on the marketing gimmicks but that's how sales are made from creating interest. I certainly wouldn't worry about it either and just change oil on a regular basis without doing "extended drain intervals" as is the phrase often used in later years with commercial engines, and use a decent filter ( no Chinese knock offs that look like genuine brand name filters ). Change your fuel filter often as well and again with a genuine brand filter and a person is way ahead of some that try to tell themselves the dash will let them know when to lift the hood !. I already know from seeing your approach to prior vehicle maintenance that your way ahead of the curve when it comes to taking care of your investment.

As to the DT466, I don't believe that is the engine that Ford used from IH, this is a heavy engine and also did not use that high pressure oil system for the injectors as it has its own external injection pump with the high pressure lines running to the injectors. The DT466 is an inline 6 cylinder engine by the way. The reason that comment interested me is that I happen to have a tandem that my dad bought new way back that has the DT466 and when I do an oil change on it, its oil does stay clean for a while ( unlike all this garbage with the EGR crap these days ). Isn't the 7.3 something like a 444 ci and yes a V8 with all that high pressure oil injection system ... never owned one but they were impressive for power/torque in their day without a doubt.

64BAwagon · May 21

I mis spelled my comment, it should have said "or" instead of "of" I was speaking of two different engines that used the high pressure oil system to drive the injectors. The 466 is used in a lot of vocational trucks and many school busses. It also comes rebadged as a Detroit diesel series 40.

Chuck FB · May 21

13 minutes ago, 64BAwagon said:

I mis spelled my comment, it should have said "or" instead of "of" I was speaking of two different engines that used the high pressure oil system to drive the injectors. The 466 is used in a lot of vocational trucks and many school busses. It also comes rebadged as a Detroit diesel series 40.

And I had my mind on the older DT466 as I knew they kept on cranking up the hp and torque on them but what I didn't realize is that they switched over from the typical injection pump of the first ones in the late 1970's to the HEUI being introduced in 1994 it says with an overlap of the later type of mechanical fuel injection pump for a few more years on certain applications. A lot of years and changes along the way it appears with that engine, that's really no different than a Cat 3406 that went through a variety of fueling systems and series names or the Cummins 855 with its cam series. The sad part is that its the government that forced them to do the impossible with engine emissions which shoved them all into history by way of ending production or the toilet by way of giving themselves a black eye by creating a complete problem child with inventions strapped on that were doomed to fail. The little history blurb I found gives a dry weight of the DT466 as 1425 pounds, a little on the heavy side for a pickup but perfect for school buses and some motorhomes. By the way the tandem we have is a 1981 S1900 series and I believe its engine was rated at 210 hp which may sound horrible in this day and age but it moved quite a few loads of grain as well as gravel in its day and I know I was at if not above 60000 lb gross at times ( slightly over loaded ! ). But going back to your comment on the oil turning black instantly after an oil change, yes I could see where the 466 would have gone into that theme as well after they put the HEUI system on it. I did find a figure on the 7.3/444 for weight, its a pig too at 920 pounds and makes me wonder what the big three pickup diesel engines weigh these days.

64BAwagon · May 22

My 2025 is an exact duplicate of my 2024 gasser except for the Duramax and the dual alternator setup, it weighs 800# more than my gasser.

Chuck FB · May 22

38 minutes ago, 64BAwagon said:

My 2025 is an exact duplicate of my 2024 gasser except for the Duramax and the dual alternator setup, it weighs 800# more than my gasser.

Was your 2024 model also a 3500 ?. I gather you had the two battery system in your 2024 but not the dual alternators. The only other item that comes to mind that I believe would be different is your duramax being a 3500 will have the 12" rear diff and I have no idea what its weight is compared to the 11.5" diff. I wonder how much of the extra weight of the duramax truck is the actual engine vs all that lovely emissions equipment as I've assumed a dpf is fairly heavy but never had one in my hands to know, and then there is the def tank and I don't know if factory weights calculate a full tank of fuel ( diesel more dense than gasoline ) and if they figure in a full tank of def, probably more coolant capacity, more engine oil etc. I know, that's a rather deep dive I just did but certainly there are items associated with the diesel platform that ultimately add weight to a road ready truck that are not just engine block related but of course that engine is going to be one hefty piece of extra weight over an L8T block. Lately I was comparing the axle weights of my gas truck to a farmer who weighed his 2024 duramax and the glaring difference was that front end weight and where I can squeak by with 40 psi in the front tires, the duramax with one person in the cab and nothing much else in the truck would require 50 psi to carry its front end.

64BAwagon · May 22

Both were 3500's identically optioned with dual batteries. The 2025 had the L5P, dual alternators, upfitter switches and the high idle option. The rest is exactly the same RPO codes as the 2024 other than the 2025 is Sterling Gray and the 2024 was Cajun red tintcoat which may have added a few ounces due to the tri coat paint. LOL. I am sure all the ancillary equipment for the emissions items you mentioned add quite a bit to it. I know the rear diff on the diesel does have additional gussets that the gasser didnt but I dont know for certain that the ring gear size is different. I do know that they were both underfilled by a qt of gear oil so that remains the same.

Chuck FB · May 22

34 minutes ago, 64BAwagon said:

Both were 3500's identically optioned with dual batteries. The 2025 had the L5P, dual alternators, upfitter switches and the high idle option. The rest is exactly the same RPO codes as the 2024 other than the 2025 is Sterling Gray and the 2024 was Cajun red tintcoat which may have added a few ounces due to the tri coat paint. LOL. I am sure all the ancillary equipment for the emissions items you mentioned add quite a bit to it. I know the rear diff on the diesel does have additional gussets that the gasser didnt but I dont know for certain that the ring gear size is different. I do know that they were both underfilled by a qt of gear oil so that remains the same.

I know I've seen in video in the past as to some differences externally to identify the 11.5 vs the 12 inch diff but I've not had any desire to be crawling around under the duramax trucks at the dealership in the grime to look up close myself. So the claim has been anyway that the 2500 model with the duramax came with the 11.5 diff and possibly a bit lighter drive shaft and some torque management going on in the low gears. Where as the 3500 got the 12" and not the same torque management but it would be tough for even a GM tech to find out every detail either if GM doesn't want certain information known. I am not sure when the 12" diff even came out, I think its only in more recent years and would imagine due to the cranking up of the power output that they felt the need to even put a 12" in the truck. The duramax has that larger steel dampener or whatever it is on the nose of the pinion, that looks like a hefty piece. Oh that's right, the diesel is being under filled on the rear diff just like the gas version, isn't that nice ( that adds up to dollars of oil savings in someones pockets ! ).

I am assuming then that you have the same tailgate on both trucks and I think the standard tailgate is steel although I never confirmed that, but for sure the origami tailgate as I call it that I opted for is all aluminum as the magnet test proved that. If one tailgate is heavier that the other, that I could not tell you.

64BAwagon · May 23

I only have a few hundred miles on mine right now but I have never once seen it in first gear, always starts in second.

bruceb58 · May 25

On 5/23/2025 at 4:08 AM, 64BAwagon said:

I only have a few hundred miles on mine right now but I have never once seen it in first gear, always starts in second.

What does it do in tow haul mode?

MG386 · May 25

verified with idash, truck always starts in 2nd gear for normal mode. Tow/Haul it always starts in 1st gear. 2024 3500 L5P SRW

64BAwagon · May 26

I havent towed with mine yet, I am waiting for the new 5th wheel hitch to arrive. The guy that bought my 2024 made me an offer if I would leave my old hitch in the truck. I got about 20% less than the price of a new one in exchange for my 5 yr old one. That way he didnt have to mess with the RV dealer to get it installed, his new trailer was similar to mine.

On a side note, the 2025 I just bought cost us approximately 10 times what my first new truck did in 1981. The 81 wasnt a 3500 diesel for sure but it was a common model back then, V8 shorthbed

ShotgunZ71 · May 27

When changing oil, put in the required amount by the manufacturer, not what the dipstick says. Once this is done, then you have a level on the dipstick that you know is the true "full" mark.