2007 LBZ Duramax burning 5/40 Mobil Syn

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Zad

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Apr 26, 2013
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Rocky Mountains of BC
I have an '07 LBZ Duramax with 78K miles that I bought from a fellow I know. When I bought the truck, he told me it had never burned any oil and he was running 15/40 dino (I believe him). I live in Southern BC, Canada and winter temps routinely get down to 0 to -4 F with an average of 14F. I do lots of short trips in the winter and longer trips pulling an #8000 trailer in the summer. The truck does have a block heater and sits outside. Because I do lots of short trips in the winter around town I put in the 5/40 syn and over 4000 miles it burned two quarts. While this is still within the oil burning specs from GM, I just don't like the idea of burning oil. I am considering going back to the 15/40 dino. I would prefer to not get into the UOA's and extended drain intervals and am wondering if, given my location and how I use the truck, I would be putting undue strain on the truck (starter, batteries and engine) going back to the 15/40 dino oil for the winter, particularly given the fact that my winter driving is mostly short, in-town trips where the truck never really heats up. The other factor is that Walmart just had a killer sale on Castrol Tection 15/40 and I was able to get 5 gallon pails for $19.
 
Sounds like a nice truck...a workhorse...

You're pretty hard on the truck; very cold temps, short trips in winter, 8000# trailer... I would stick with a 5W40 in the winter for the cold starts, but no worries using a dino 15w40 in the summer. Under heavy trailering/use, I wouldn't worry much about 1QT every 2,000 miles...
 
As it turns out, the last 4000 miles has seen no trailering at all, those burned 2 quarts were just from around town and a number of 400 mile trips. I am curious to see how much oil it does burn when we start towing lots. The computer tells me I have 50% oil usage left before the next recommended change and I am going to top up the oil before we start towing and see how much it burns over the next 1/2 of the oil cycle while towing.
 
Originally Posted By: Astro14
Sounds like a nice truck...a workhorse...

You're pretty hard on the truck; very cold temps, short trips in winter, 8000# trailer... I would stick with a 5W40 in the winter for the cold starts, but no worries using a dino 15w40 in the summer. Under heavy trailering/use, I wouldn't worry much about 1QT every 2,000 miles...


I agree. Also, there are better 5w40's out there than Mobil's (assuming you're using TDT), in my opinion. I ran M1 TDT in my Dodge for a while and dumped it early because of high oil consumption. I switched to RT6, and oil consumption has been much less.
 
I have TDT in my '06 Cummins Ram in my sig, and it does burn some, roughly a quart every 2-3K-but, that allows me to extend my OCI. I have a recent UOA that shows a TBN of 8.0 after 6K and TWO & A HALF YEARS!
 
I bought 6 x 12 QT cases of M1 TDT on clearance (0.98/QT) but I run it in a Volvo turbo...near zero consumption...I realize that's a completely different engine, but the oil has performed well for me...
 
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Yes, I thought I might have acted hastily in dumping the TDT after only 6k miles. But I was used to getting about 3k miles per quart consumption on my beloved Premium Blue Classic 15w40, and I was getting about 1qt/2k on TDT. RT6 has worked out well for me, though. I was getting about 1qt/3k consumption on the RT6 so it was at least a wash with VPBC. Then I learned to leave the sump 1 quart low. Now I am getting about 1qt/9k.
 
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If you look at the duramax manual, you're not supposed to use 5w-40 for towing anyway. I believe only 15w-40 is approved for towing.

I've been running 15w-40 all year round in my duramax and two of those years were 10 mile daily-drives to work and back. My winter temperatures are dramatically colder than yours most of the time.

I've had no consumption on the 15w-40. I'm at close to 10k miles on this OCI.
 
It does not get that much warmer where I'm at; my avg low is 18 and we get down to zero F each year, though not with regularity.

I have had excellent success with 10w-30 HDEO conventional lubes in my Dmax. You might consider that as an option.

Generally, the Dmax really does not care what oil you use, as long as it meets the proper API specs.

I would suggest you consider at 10w-30 CJ-4 dino; Rotella, Delo and Delvac all make that vis, but not sure how easy they would be for you to get. Some decent Canadian brands probably offer similar products.

And not for one second should you worry about or fear using a thinner conventional lube when towing. I used my "thin" 10w-30 dino pulling a travel trailer over the Rockies, into the summer heat of AZ and UT, then back over the Rockies and got excellent wear protection. You don't "need" 15w-40 to get good protection.

Conventional 10w-30 HDEO gives great wear protection, easier cold starts, all at a good price. Hard to be "better" than that.
 
Ok, thanks guys. I am hoping I can get the block heater issue with the LBZ figured out. When I plug the truck in at temps warmer than 0F the truck throws codes that change the shift points of the tranny. Royal PITA. If I can get this issue fixed I will go with the 15/40 as I have a bunch of it for super cheap. If not, I will go to the 10/30 HDEO as Newton suggests.
 
The block heater is not recommended for temps above zero. I know that seems silly, but it's a commonly known issue in the Dmax community.
 
My $0.02

You need a commuter vehicle, ahort trips are killing your truck,diesels are born to run. You need to burn off all the condensation building up, and with a 10 mile ride it isn't happening. When do go on an extended run all that condensation is boiling off along with some of your oil..
 
I completely agree...we do have a commuter vehicle and the LBZ was bought for towing our 25' camper with a slide during the summer. The winter months bring shorter trips when my wife has the commuter. 3 times a week all year long I drive an hour of highway miles, summer it sees lots of towing and the rest is about town. It is very likely too much truck but jeez I love it. Have similar setup as you, EFI tuning (for economy and towing), t-case fix, 265's and a 4" exhaust...gets 20 mpg and drives and pulls like a beast. Despite the fact that it is likely way more truck than we need, I really doubt I could ever go back to a gasser. Although, a guy I know was telling me about his ecoboost Ford and how impressed he is with it. While I am somewhat curious, I just think I have too much diesel in me now...although that song may change if/when I have to deal with a major repair, lucky so far.
 
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Well those hour highway trips are a good thing. I too probably don't need a diesel but I do love it so and its something I have always wanted, and 6 years ago I got one !
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4" exhaust eh? That sounds like an avenue to explore, which will excite my wife to no end !
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Block you EGR and reroute your PCV, it'll stop all the gunk from building up in the intake, efi can ghost out any CEL's that pop by blocking the EGR. All you need is a blocker plate ,alot of penetrating oil on the two bolts, a strong arm,loosen the 2 bolts,insert and tighten = DONE. PCV is even easier,just look for a kit on the net. And as suggested I'd try a 10w30 HDEO. Ironically I have a friend who has a F-150 Eco and he raves about it.. hmmmmmmm

Best of luck with the truck Zad.
 
I have already done the EGR block and am on the fence for the PCV reroute...not sure which way to go on that one so for now, nothing. As you hint at, these things can be major money and time pits and I have reached my limit for now. I am very happy with the improve mileage and performance of what I have done so far and looking forward to the camping season to give the motor some good exercise.
 
Originally Posted By: Zad
I have already done the EGR block and am on the fence for the PCV reroute...not sure which way to go on that one so for now, nothing. As you hint at, these things can be major money and time pits and I have reached my limit for now. I am very happy with the improve mileage and performance of what I have done so far and looking forward to the camping season to give the motor some good exercise.


PCV reroute just vents exhaust gas gunk to the outside rather than back into the intake. It is suppose to be an "off-road" mod only , but they have to say that. I went through emissions testing the day after and no issues,not that there would be any.
Not endorsing ,but heres what I used if and when you decise to do it..

PCV reroute
 
I too have an '07 LBZ. It has burned about a qt. every 3k when I use Rotella 5w-40 syn. pulling my 40' fiver. When using Amsoil 15w-40 it doesn't burn any. I have used other brands of 5w-40 syn. such as Delo and Mobil-1 without issues. I used to use Rotella 5w-40 in my diesel pusher motor home and it too burned a some between changes.

With a 50K + dollar investment in a truck, I refuse to use anything but syn. oil even if the chances of oil related issues are one in a million! It's sorta like flood insurance.
 
Originally Posted By: oilgeezer
With a 50K + dollar investment in a truck, I refuse to use anything but syn. oil even if the chances of oil related issues are one in a million! It's sorta like flood insurance.


With all manner of things costing so much these days, I cannot afford to waste money on a product that does not give a good ROI. Hence, I don't run synthetics for OEM OCIs.


Welcome to the site, BTW.
 
My 07 LBZ has 89K on it and I've only run 15w-40 (dino) in it since new. Below 65K it burned a quart or more every 7500 miles (my OCI) but now has settled in. My last change saw no oil consumption at all. I drive it work on occasion (30 mile round trip) and also use it to pull a 7K toyhauler.

Don't see the need to buy expensive synthetic for my truck.

SP
 
Not same engine or truck. I use rotella 10w-30, 7,500 oci's. 197k on clock of 97 powerstroke. I paid [censored] hard earned money for this clean single owner. With 40k five years ago. I use good oci's not the highest oil. I know guys running rotella conv 10-12k and uoas come back run 15K.

Kc
 
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