2004 Duramax 8K Shell Rotella 5W40

[KevinsDMAX]

Hello All,

Attached is my most recent UOA from my truck. This oil has been inservice for about 9 months. It has has about 20% heavy towing, and has gone up the "Dalton Highway" hunting Caribou (600 miles of dirt road...might be the cause of silicon). Blackstone flagged the silicon...recommended 2K then resample. Previous UOAs haven't shown more than 9, but max of 6K of use. Should I be worried about 35 PPM of Silicon?

ALUMINUM 2
CHROMIUM 0
IRON 11
COPPER 4
LEAD 2
TIN 0
MOLYBDENUM 60
NICKEL 1
SILVER 0
TITANIUM 0
POTASSIUM 0
BORON 57
SILICON 35
SODIUM 5
CALCIUM 1017
MAGNESIUM 1365
PHOSPHORUS 1260
ZINC 1417
BARIUM 0
SUS Viscosity @ 210F 70.4
cSt Viscosity @ 100C 13.05
Flash point in F 405
Fuel % 0.5
Antifreeze % 0.0
Water % 0.0
Insolubles % 0.2
TBN

By the way...Oil Life Monitor was at 3%.
Kevin

 

[roadrunner1]

Are you using an aftermarket air filter/and or have you checked for loose connections in your air system? Good job "utilizing" the OLM to the end.

 

[Lead Shoes]

If you took 600 miles of dirt roads I would not be worried about 35PPM silicon...

Looks like a great UOA to me

 

[KevinsDMAX]

I'm using a stock airbox system. The filter is about 20K old. Being in Alaska I have a lot of idle time. Just check the fuel used over this time the oil has been in the sump and I used about 550 gallons of fuel...and still counting.

Will check for loose connections...should I dump this oil or continue use per Blackstone's recommendations?

Kevin

 

[Highline9]

check the clamps on the intake connections. I noticed that my factory intake clamps get loose or the silicon rubber srinks.

 

[dnewton3]

Overall, good report. Seems like the engine is doing well (not unexpected for a Damx).

The Si is indeed a bit high, but the good news is that it didn't manifest into wear issues. If not for the Si, you could easily push the OCI out. See if you can find the Si source, and eliminate it, and then you'll probalby be able to double that OCI with no issues. Keep pushing out your OCI so that you can at least break even on the investment. If you cannot, you're in a position where you're wasting money, and would be better off with conventional oils.

Note: Silicone and silicon will show up as the same thing in a UOA. Silicone sealant, from any recent engine, might explain the Si count. If not, then it's likely sinicon dirt intrusion. Check your entire intake tract carefully.

 

[Jim Allen]

Also, check things like dipstick tube sealing, crankcase ventilation, oil filler cap sealing, etc. Those are other ways dirt can enter the crankcase and manifest as a high silicon reading. One quart of oil added carelessly can allow dirt to enter the crankcase via the oil filler. Ditto for checking the oil and letting dirt in via the dipstick or dipstick tube. These were lessons taught me by members of a family that spent decades running expeditions in the Sahara desert and other remote African locales.

That said, especially in the circumstances you outlined, 35 ppm is not a terminal case but you want it lower.

 

[KevinsDMAX]

I did have the oil pan removed and replaced, because of a small leak, but that was on the last fill, could there be some residual Si still in there (Chevy doesn't make a oil pan gasket, so they used silicon)?

As for the conventional oil use...would love to, but don't think conventional oil would like the the temps of today high -19 F / -35 F today.

Kevin

 

[Jim Allen]

Unlikely to be the sealant after two OCs... check all the stiff listed and then you'll see the next UOA.

Well, those temps do justify the use and expense of a synthetic ( : < ), but I think you could stretch it out to a 10K OCI next time seems like and get your money's worth more ... based on that UOA.

 

[KevinsDMAX]

Originally Posted By: Jim Allen
Unlikely to be the sealant after two OCs... check all the stiff listed and then you'll see the next UOA.

Well, those temps do justify the use and expense of a synthetic ( : < ), but I think you could stretch it out to a 10K OCI next time seems like and get your money's worth more ... based on that UOA.


Actually this is the second fill, not the third...will check the intake system tonight.

 

[dnewton3]

If the pan was sealed with Si, and you're only on the second OC, then it very much could be the sealant. Espcially with the absense of high wear metals, indicating that dirt may not be present.

Also, if you can get your hands on T5 10w-30, you can get the same cold crank benefits for far less money; rated right with the T6 in that regard. T5 is at most all WallyWorlds sitting right next to the T6.

The Dmax is notoriously easy on oil, and the 8k mile OCI is nothing but ordinary.

 

[KevinsDMAX]

Originally Posted By: dnewton3
If the pan was sealed with Si, and you're only on the second OC, then it very much could be the sealant. Espcially with the absense of high wear metals, indicating that dirt may not be present.

Also, if you can get your hands on T5 10w-30, you can get the same cold crank benefits for far less money; rated right with the T6 in that regard. T5 is at most all WallyWorlds sitting right next to the T6.

The Dmax is notoriously easy on oil, and the 8k mile OCI is nothing but ordinary.


Thanks for easing my mind about the SI. I did check my intake and all seemed tight.

As for the T5, I scored about 15 gallons of Rotella T 5W 40 (non T6 CJ-4) about 2 yrs ago for $11 each, when my stash runs out, I'll look and see what lube will give me the best ROE.

As for the 8K mile OCI, not many people run their vehicles in the kind of conditions that we have up here, and I wanted to ensure that I was still OK with going longer.

 

[dnewton3]

Originally Posted By: KevinsDMAX
Thanks for easing my mind about the SI. I did check my intake and all seemed tight.

As for the T5, I scored about 15 gallons of Rotella T 5W 40 (non T6 CJ-4) about 2 yrs ago for $11 each, when my stash runs out, I'll look and see what lube will give me the best ROE.

As for the 8K mile OCI, not many people run their vehicles in the kind of conditions that we have up here, and I wanted to ensure that I was still OK with going longer.


Excellent score on the oil!

One note; fresh, sealed oil will last about 5 years in the bottle, and then it becomes a bit questionable as to the additive package starting to separate. There is no hard-and-fast rule for exactly how long it lasts, but that is a generally accepted limit before concerns start. You could do a VOA before installing to assure the oil is still good, but that would erase the fantastic savings you got with the original purchase price. Also, you may have bought it 2 years ago, but it may actually be older than that. I'm sure there is a way to read the date code on the jug, but I have no idea what it would be.

At 2.5 gallons per OCI, you're not going to be able to use it all in the 5 year time period, unless you have another vehicle to use it in. Even though the oil would be able to go much further than 8k miles, you got it cheap enough that you could dispose of it a bit early (I hate to see good oil wasted ...)

Or, you can always hold back enough for what you need for the next year or two, and sell the rest to a local friend.

As for this current UOA, and your upcoming one, I'd say to stay the course. You've assured that there is no Si dirt leak to the best of your knowledge, and it's very likely the Si is from the pan sealant. Run another 8-10k miles and do a UOA on the next oil sump load. If the wear is similar, and the Si drops, then you've got your answer; it's the sealant and nothing to worry about. If the Si is still high and wear increases, you've got an undesirable answer that you didn't want to hear. But either way, you'll get an answer.