I don't have any heavy towing with the L5P yet but my LB7 and LBZ equipped trucks would use a little oil under those conditions towing, especially in hot weather. I never ran synthetic so having 5W on the low end of the temp range may also make a difference. I don't know what GM's warranty statement is for oil consumption of the newer DPF equipped vehicles but at one point it was not more than 1 qt per 1,000 miles and then they started stating 1 quart per X gallons of fuel consumed which was a better measure of the amount of work the engine was doing. In any case your consumption is well under what used to be considered acceptable.

I am also interested in the experience of others as to what is considered normal. In light usage my oil consumption is insignificant. I did the first complete fluid change at 1,000 miles and with just over 4,000 on the replacement oil it is still at the full level.

Did you do the last oil change yourself or was it done at the dealer? They aren't always careful with getting the right amount in. I have a good dealer who did the free changes on my 2016 Corvette Z06 but there were many stories about dealers who ended up overfilling these vehicles because they have a dry sump engine with two drain plugs (crankcase and oil tank) and in many cases the dealer only pulled one plug leaving the engine partially filled and when they added 10 quarts on top of the remaining old oil the combined oil found places to come out.

 

Thanks. I'm thinking it's probably okay but I was hoping to hear others' experience.

I did the oil change myself. I have a 2-quart bottle that I fill in order to get exactly 10 quarts (the oil I've been using comes in 4-quart jugs) into the crankcase, and I always check the oil after filling and it's right at the top of the cross-hatches on the dipstick.

 

I've used Mobil 1 for turbo diesels in my LB7 since the oil hit the shelves in maybe 2004. Got 400k now and I did 3 months towing campers all over the country back in 2013. 30k miles in 3 months. Add that to towing my 10k lb boat all over creation and I've done a lot of towing with Duramax and Mobil 1. Have never added a drop of oil to my truck over 16.5 years of driving it. Not sure about L5P but as far as I know it's not normal. Maybe it's a break-in thing and will go away soon?

 

I'd be using the recommended 15W-40 for the operating conditions you are describing.

GM suggests 5W-40 for easier starting below 0*F. (for the 6.6L)

Mobil 1 Delvac 1300 Super is available in 15W-40, if Mobil is your preferred.


https://www.mobil.com/en/mobil-delvac/products/engine-oils/mobil-delvac/mobil-delvac-1300-super

 

Is that a synthetic like Mobil 1? Checked out your link and it lists as just Mobil, not Mobil 1. Can't find any reference saying it's syn or not syn. Does say up to 1.5 x extended oil drain intervals though.

Digging around on Mobil's website it appears that Delvac 1 ESP may be the syn version of Delvac but it's only available in 5W-30, 0W -40 and 5W-40 flavors. It appears more geared toward 18 wheelers and such though.

I went full syn with mine because I think (think) the turbo could benefit from the high cook temp of full syns. And, because I ran it in all my previous gas trucks and other vehicles for close to 1 million combined miles w/o a hiccup with 10k mile ODIs.

 

Last month I made a trip to Kansas from NC (not towing). I had changed the oil right before departing and upon return the oil was showing in between the hash marks. I was wondering the same thing on the consumption...my LMM and LML never used oil like this. It was about 2600 miles. Looked in the diesel portion of the owners manual and it says anywhere between the marks is good.

 

I've had 4 Duramax trucks starting with a 2001. Towed fairly heavy with them all especially the last two. All seemed to use about 1 quart in 5K mikes when towing. When not towing much they don't use much at all. All four have had Mobil 1 Diesel Truck 15W-40.

 

BTW jd, I'm just down the hill from Badger in Reedley.

 

Beautiful area. Unfortunately for me, when Phil Murphy said he wanted to make New Jersey the "California of the East" I don't think he was talking about the sequoias.

Anyway, thanks for the input. We are in Half Moon Bay now and I just had an oil change (brought my own oil/filter to a Jiffylube; I brought pretty much every tool I own but drew the line at my filthy 15-quart oil pan). They said it was 1/2-quart low, and I last topped it off in Las Vegas, so that's about 1000 miles ago (about 75% of which were towing miles, with many of them extremely hard since we took the scenic route through the mountains to Badger). We're heading up toward the redwoods today and I'm planning on stopping at an O'Reilly to stock up on more oil and DEF.

On that note, the guy who programmed the DEF readout in the DIC is an irredeemable imbecile. Why the hell does it just say "level OK" until you're about to run out of DEF, and then it gives you the mileage to empty?! I'm just going to ride around with about 15 gallons of DEF because under these conditions it seems like I'm using about a gallon every 500 miles or less.

 

I suspect because of the caustic nature of DEF they are probably using an optical sensor array to read the level and it is only designed to show level changes when it is fairly near the end of the fluid range. I agree it is irritating; maybe when these systems were first developed the engineers expected DEF to be a fairly short lived emissions technology so they didn't go with more involved instrumentation.

 

Is that your trailer the Passport Ultra-light?? How are you at 19K GCW? Maybe more like 15K and that isn't even making that truck grunt. More or less your truck weighs like 7700 lbs empty as in empty fuel tank. Add some people and fuel say 8200 which says that trailer is 10,800. You can drive into a CAT scale to see what it weighs but not sure I ever seen a 10,800 travel trailer. I don't know how your tail of the truck is down with a 3500 but it doesn't appear to me that you have a WD Hitch on it or it isn't setup correctly. My 2200 lb pin weight 5th wheel levels my truck yet the longer lever weight on the tongue of the trailer does help with drop.

As the trucks age they will use less oil when towing. My LBZ when it was newer religiously used a qt when towing then didn't use anything when it got up say past 30K miles. My current L5P used a qt on it's first tow but with 20K miles on it is uses less and less. I suspect as you get more mileage on the truck that it will use less oil but 1.5 qts /4000 miles while towing isn't anything to worry about.

No need to put that 5W-40 oil in these trucks while living in NJ. We might see all of 5 days with the temp below 10 degrees and that is where I live not close down to the city like where you are.

1qt per 1,000 miles gets you sued in this country as that was the cutoff point for oil usage lawsuits. Figure it this way 1qt/1000 miles says you change your oil in between every oil change on your average car and that doesn't fly.

 

We've got a 2003 Duramax/diesel/allison combo with about 140,000 miles on it and it has never used any oil. We've always used Mobil 1 in it from the start. We did have to have the injectors replaced at 99,000 miles and GM extended the warranty on those to 200,000 miles, but only 7 yrs and ours was 9 yrs old! Go figure.

 

So...
No negligible oil use.. now... here was pattern,

2017, from new, 50k miles now, 18-19k weight total towing Airstream trailer, used some oil, about 1 quart from new and on each of first 2 oil changes by dealer at about 6k miles each (oil monitor said there was about 1500 miles left when changed). DEF use about a gallon per 200 miles using Blue DEF. it improved a bit over time.

I switched to T4 Shell Rotella for 2 oil cycles after, to about 23k. I burned about around 1/2 quart per oil cycle and changed under 6k miles. The regen cycles were obvious, requiring extended drive time. I was using about gallon of Blue DEF per about 250 miles.

Interesting, I changed to O’Reilly DEF and the DEF mileage jumped immediately to over 300 miles per gallon.

I have run T6 Rotella since 23k.

First oil cycle used less than 1/2 quart. DEF use dropped to about 350 miles per gallon. The last change was July 2020 about 43k. I changed oil today at just over 50k.

I pull no faster than 65mph. Period.

I use tow-haul unless on level road and low winds.
When climbing or descending hills we drop 1-2 MPH per % of grade. I try to keep RPMs well under 3k on engine brake, as rule of thumb.

When leaving from a stop I gradually roll power to just over 2000RPM and hold throttle steady... let the engine pull to speed. I rarely force a “downshift” to adjust speed.

I let the engine slow the rig, minimal braking.. to a coast where necessary and possible.

Last week we pulled 800 miles and used no oil. There were only 3 times we went into engine brake, never went over 2500RPM. Using a Big Ben tablet and big fat pencil I got 12.4 MPG.

the truck is a BEAST. I can make it get 1 MPG when I MUST to blend into traffic... or drop to 55 MPH for 15 MPG

IF I RUN THE TRUCK EMPTY I get 24-26 MPG at 70MPH... I get near30 when chugging around town under 59 MPH

If anything changes I will try to let you know.
Ping pack for other discus..

 

So...
No negligible oil use.. now... here was pattern,

2017, from new, 50k miles now, 18-19k weight total towing Airstream trailer, used some oil, about 1 quart from new and on each of first 2 oil changes by dealer at about 6k miles each (oil monitor said there was about 1500 miles left when changed). DEF use about a gallon per 200 miles using Blue DEF. it improved a bit over time.

I switched to T4 Shell Rotella for 2 oil cycles after, to about 23k. I burned about around 1/2 quart per oil cycle and changed under 6k miles. The regen cycles were obvious, requiring extended drive time. I was using about gallon of Blue DEF per about 250 miles.

Interesting, I changed to O’Reilly DEF and the DEF mileage jumped immediately to over 300 miles per gallon.

I have run T6 Rotella since 23k.

First oil cycle used less than 1/2 quart. DEF use dropped to about 350 miles per gallon. The last change was July 2020 about 43k. I changed oil today at just over 50k.

I pull no faster than 65mph. Period.

I use tow-haul unless on level road and low winds.
When climbing or descending hills we drop 1-2 MPH per % of grade. I try to keep RPMs well under 3k on engine brake, as rule of thumb.

When leaving from a stop I gradually roll power to just over 2000RPM and hold throttle steady... let the engine pull to speed. I rarely force a “downshift” to adjust speed.

I let the engine slow the rig, minimal braking.. to a coast where necessary and possible.

Last week we pulled 800 miles and used no oil. There were only 3 times we went into engine brake, never went over 2500RPM. Using a Big Ben tablet and big fat pencil I got 12.4 MPG.

the truck is a BEAST. I can make it get 1 MPG when I MUST to blend into traffic... or drop to 55 MPH for 15 MPG

IF I RUN THE TRUCK EMPTY I get 24-26 MPG at 70MPH... I get near30 when chugging around town under 59 MPH

If anything changes I will try to let you know.
Ping pack for other discus..

first.. what do you have for a truck... I assume a 3500 l5p due to your trailer weight but you have no rig in your sig...

second.. there is NO WAY you are getting 30MPG empty or otherwise with an L5P unless its being pushed from behind..
same with 24-26MPG empty at 70mpg,.. NO WAY..

I have not towed heavy with mine yet.. so I cant speak to 300 miles per gallon of DEF.. I seem to be getting more like 1000 miles to the gallon.. which is right at 2% dosing per gallon of fuel... assume you milage is 10mpg instead of my 19 MPG and that would halve to 500mpg.. then likely figure a higher dosing % during high boost etc.. so 300-400 MPG might be accurate...

but your MPG are in fantasy land..

 

I had the same concern then I found this:

https://static.nhtsa.gov/odi/tsbs/2016/MC-10137984-9999.pdf

Seems like it is normal under towing conditions.

 

Yeah that service bulletin has been discussed ad nauseam. Just because GM came out with a service bulletin that says it's normal to use a quart of oil every 350 miles doesn't mean it's so. It appears to just be a golden parachute to relieve them of any warranty liability to fix an oil burner presumably either because they don't know how or they're unwilling to do so.

Either way, it's reprehensible that a U.S. automaker would come out with such a bulletin. Fill up your fuel tank and dump in a quart of oil twice a day? How do they say that with a straight face?

 

Yeah that service bulletin has been discussed ad nauseam. Just because GM came out with a service bulletin that says it's normal to use a quart of oil every 350 miles doesn't mean it's so. It appears to just be a golden parachute to relieve them of any warranty liability to fix an oil burner presumably either because they don't know how or they're unwilling to do so.

Either way, it's reprehensible that a U.S. automaker would come out with such a bulletin. Fill up your fuel tank and dump in a quart of oil twice a day? How do they say that with a straight face?

calling this twits face straight... ?
GM logic.. comon'man....

 

I like fantasy land.... cool rides there.....

 

my reaction after hearing 30MPG L5p... after spitting my AM coffee through my nose...

 

I cant imagine the DOC / SCR / or DPF would survive long in a 2.6 q per 1000 mile enevironment ... low ash oil or otherwise..

this is probably the limit because any more than that and you would likely have a runaway diesel.. it would burn the oil after key off...

 

Et al,,,
My apologies for my mileage bold face lie.

Second, I may have failed the OP as well as I intended no thread unraveling.

Mea culpa, mea culpa, mea maxima culpa.

Not good for me to type after taking my anti-seizure med and trying to post. No excuse. I should have proofed the copy.

We have 2017 2500hd (I thought I had that in my profile.. I will fix that ASAP)

There are so many factors to “mileage”, etc.. we can only generalize after observation.

We live near I35, traffic runs 75+MPH and that is where I have had some mileage over 25MPG... NOT TOWING. Nothing in the truck but me. But the air is moving pretty fast when in a constant slug of traffic.

Traffic does change it.. lower of course. And yes, I do run with the trucks sort of obeying the speed limit of 70MPH, not 75MPH.

When running alone (Texas back roads, no trailer) I get over 20MPG average on the pencil. I drive 60-65 unless I need to make up time and run posted limits.

In town I hit maybe 15MPG on a tank but speed limit is 40 MPH and lower.

The Airstream is 1999 3 axle. It’s GVWR is 9800#. I have upgraded to 12”drum and 3750# axles plus frame strengthening for 11,250# possible weight of the trailer. When my bride has it packed, we are right at 10,000#. Add in the 2500HD Crew cab, fiberglass bed cap, 200# front guard, 500# of gear, 200# WD hitch, 5 gallons extra diesel and 5 gallons generator fuel, full fuel, myself and a friend over 275# each plus my dog we crossed CAT scales over 18k...

On our run to Louisiana and back we got 12.6MPG on the pencil.. 860 miles towing.

Hope this helps my penance for my transgressions..

Peace

 

Diocsesan

ok .. had to look that one up....

Definition of diocesan : a bishop having jurisdiction over a diocese Examples of diocesan in a Sentence Recent Examples on the Web The diocesan website includes a statement from Dallas Bishop Edward Burns connecting the need for social distancing with the story of the Good Samaritan.

I am glad we got that cleared up... clearly I must be off my meds this AM .. that is just not making any sense to me....?

 

JD.. cut paste, then did edit... apparently duped.

Using the web browser is causing a problem. Will change method

 

out of 2767 fuel ups.. and over 1 million miles none of the 48 vehicles on fuelly got a tank better than 20.. only less than 1% of those fuel ups got 20...

and none of the 48 '27 2500hd diesels have an average better than 18

these numbers jibe with my '19 and every guys truck around here that I am familiar with.. just in case anyone reading this thread is wondering what is wrong with their trucks MPG.. this is REALITY ...

unicorns do exist possibly.. but I have never seen one...

 

 

I was referring to the claim of 20mpg at 60-65, 15mpg around town, and 12.6 towing his trailer.

My 2017 with 305/55r20's has been running consistently 1mpg less than DIC ( I can print the excel sheet if you're interested), and on the highway cruising I can average between 19 and 22 depending on the day. This assumes nothing over 70mph, no windy conditions, no load other than myself and maybe two of my kids. I have never done a fill up after only driving highway, so I guess technically I cannot strictly verify those numbers. I can only offer my observations while on the highway and compare it to what my DIC reads compared to hand calc'd numbers.

15 around town is normal. 12.6 towing seems a little high to me, but not out of the realm of possibility.

For anyone looking for a good tracking app, I like AUTOSIST. The free version only lets you track one vehicle at a time, but being able to export everything made trading my last truck in much smoother when I could account for every oil change, maintenance, and most every fuel up I had done in the truck. I put notes in now on my 2017 to track what the DIC showed compared to what the mileage calculated out to be. Pretty handy. You can also access it via the web, too.

 

yeah man.. sounds more down to earth...

I have a 400 mile best on my DIC at just a bit over 20... BUT that was likely on a 55-65 stretch AND 400 miles where I didnt have a REGEN .. MPGs are great right up to a REGEN .. and you will get no less than ONE per 36 GAL tank.. regardless of how you drive or soot load verified in PRINT from a GM service manual document on how REGEN is calculated and triggered.. and 36 Gal or 800 miles are LIMITS.. regardess if you have ZERO soot load at that time.. it will REGEN for 22 minutes anyway.. I have watched it now 3 times on my truck where soot loads were between 9 and 14 % and did a full 20+ minutes at highway speed to REGEN...

for my last 2860 miles.. hand calc of 17.981 MPG and that is mostly 70% 55+mph I try and limit this trucks use for short around town stuff.. this is since Oct...

 

I've got less than one regen per tank, on back to back tanks no less. My truck has consistently regen'd at 800 miles. So when I'm towing a big RV, I get a regen roughly every third tank of fuel.

 

Maybe there is part of the reason your truck broke down

GMs docs on Regen to techs state that it will regen at 36 gallons or 800 miles. Unspecified engine time and a bunch of other conditions over and above a second trigger actual soot load

 

800 miles on regens caused the injector pump to go bad? I don't guess I follow.

 

2017 L5P, almost 28k miles.

Sitting here in at the Sequoia Resort and RV Park in Badger, CA (I'm from the NYC area) enjoying an epic Duramax/camper road trip and wanted to get some input from guys who are running their L5Ps pretty hard. My rig's GCW is 19k lbs and I changed the oil (Mobil 1 5W40 full synthetic turbo diesel truck oil and a Mobil 1 M1-303A filter) just before we departed. Since then I've put on about 4,000 towing miles (the vast majority of which was highway, plus some city driving and some crawling up and down twisty mountain roads with plenty of exhaust brake usage) and another 600-700 non-towing miles. Over that interval, the engine has consumed about 1.5 quarts of oil, and I'm curious to hear if others (especially @M.A.M. and anyone else who runs an L5P as a commercial towing rig) have experienced similar oil consumption.

Your oil is going somewhere and I would imagine it's the intake.. Only use 15w-40 in any circumstance. If it's cold turn the high idle function on remote start and let it run until the oil pressure drops to below 60. My l5p pulls heavy loads every day and I use around 1/2 quart every oil change. Im running Rotella T5 15w-40. Synthetic blend. I have 220k on my truck since yesterday and im still rolling.

 

What the H you doing in CA, JD That's a long haul there driver!

Seriously, I don't care for going there at all but Yosemite is still on my bucket list.

As you well know, my L5P has spent most of my ownership period in the shop. But when I did get to run it, I did not see any appreciable oil consumption. So far, I would have to say, not even measurable. I typically pull big 5ers and gross around 23k-24k and I go west a lot so mountains are pretty common. I've always ran Rotella T4.

I ran T4 in my LML up to 333k miles and it still wasn't burning a measurable amount of oil in 10k+ oil change intervals. And I guarantee you I pulled the snot out of that truck. Big 5ers, mountains and lots of them.

 

What the H you doing in CA, JD That's a long haul there driver!

Seriously, I don't care for going there at all but Yosemite is still on my bucket list.

As you well know, my L5P has spent most of my ownership period in the shop. But when I did get to run it, I did not see any appreciable oil consumption. So far, I would have to say, not even measurable. I typically pull big 5ers and gross around 23k-24k and I go west a lot so mountains are pretty common. I've always ran Rotella T4.

I ran T4 in my LML up to 333k miles and it still wasn't burning a measurable amount of oil in 10k+ oil change intervals. And I guarantee you I pulled the snot out of that truck. Big 5ers, mountains and lots of them.

Interesting. It hasn't been a big problem for me but it was noticeable. Hoping to put in some miles with the newer (and much heavier) rig soon so I'll keep everyone posted.

As for being in CA, in both 2018 and 2019 I took the entire month of December off work and we all (me, the wife, and our three cats) hit the road and headed west. Really incredible both times. On the first trip I was constantly repairing stuff and dealing with mechanical and electrical problems because our camper had been static for 4+ years prior to the journey (I had actually been living in it in a trailer park quasi-permanently for the first three years I owned it) so all the gremlins woke up. On the second trip we had very few issues; the only thing that caused us any downtime was when one of the slide-out cables snapped while we were down in New Orleans.

There were only two instances in which I had to get outside help. On the first trip, the ball coupler on the trailer developed a crack so I had a welder in Las Vegas cut that one off and weld on a new one. And on the second trip I caught a patch of black ice in South Dakota on I-80 and the whole traveling circus wound up in a ditch in the highway median, so I paid for a tandem axle wrecker to come winch us out (miraculously, there was exactly zero damage -- and that's a 19k lb rig sailing into a snow bank at 60 MPH).

Now we have a baby girl in tow so it's going to be a little more complicated but we will make it work. Later today we are heading to a campground in Long Island for the weekend for a friend's wedding on Saturday (I wouldn't be caught dead in LI of my own volition). $70/night and no sewer. This is why I prefer camping anywhere other than the Northeast...

P.S. It will cost me $99.16 just in tolls to get to the campground which is only 70 miles away, and the drive will likely take over two hours in horrendous traffic. It's really nice of NYC to remind me why I don't miss it every time I go there, or even just through it.

 

Sorry posted in error.

 

2017 L5P, almost 28k miles.

Sitting here in at the Sequoia Resort and RV Park in Badger, CA (I'm from the NYC area) enjoying an epic Duramax/camper road trip and wanted to get some input from guys who are running their L5Ps pretty hard. My rig's GCW is 19k lbs and I changed the oil (Mobil 1 5W40 full synthetic turbo diesel truck oil and a Mobil 1 M1-303A filter) just before we departed. Since then I've put on about 4,000 towing miles (the vast majority of which was highway, plus some city driving and some crawling up and down twisty mountain roads with plenty of exhaust brake usage) and another 600-700 non-towing miles. Over that interval, the engine has consumed about 1.5 quarts of oil, and I'm curious to hear if others (especially @M.A.M. and anyone else who runs an L5P as a commercial towing rig) have experienced similar oil consumption.