Rotella T 10W-30, 5000 mi, '96 Buick RMWagon 5.7L

[WishIhadatruck]

Changed it sometime last fall with Shell Rotella T 10W-30 and an Amsoil oil filter.
Previous fill was a very short run (2k miles) of GC. I was not happy with the GC and changed it early to the Rotella T. Click here for previous UOA.
Second sample of 7/28/08 was GC with a UPF-52 filter.
First sample of 9/2/07 was Valvoline 10W-30 most likely with a cheap oil filter from my mechanic after fixing some oil leaks.
Wix air filter. Air filter changed at almost exactly the same time the oil was changed last.

Blackstone Coments:
Lead dropped nicely in this third sample out of your RoadMaster, so you've now got all perfectly normal wear metals in the oil. The fuel dilution we found last time has also improved. No moisture or antifreeze was found either, so this oil is free of contaminants. The TBN still shows active additive remaining, with a 2.7 reading, so you could still run your oil longer, if you wanted. You're sticking with 5000 or so miles on the oil, but if you wanted to stretch that to 6000 miles, it should be ine. The viscosity was normal for 10W/30 oil.

Comments welcome. Lead has definitely improved. Silicone is still a little high from what I'm used to seeing in most cars but is not far off the universal averages. The iron is up but still well below the universal averages. Overall I'm happy with this report and have the same oil in it again. I did not change the Amsoil oil filter this time. I drained out the old oil from the filter and reinstalled it.

Code:


OIL RT 10W-30 GC 0W-30 Valv. 10W-30

MILES IN USE 5.0k 5.6k 4.6k Uni Avg

MILES 125k 118k 108k

SAMPLE TAKEN 5/15/09 7/28/08 9/2/07



ALUMINUM 7 6 6 7

CHROMIUM 1 1 1 2

IRON 26 19 22 37

COPPER 3 4 5 11

LEAD 10 32 19 13

TIN 3 0 0 2

MOLYBDENUM 8 7 15 52

NICKEL 1 1 1 1

MANGANESE 0 1 0 2

SILVER 0 0 0 0

TITANIUM 0 0 0 0

POTASSIUM 4 2 1 9

BORON 14 5 7 42

SILICON 26 29 94 23

SODIUM 7 7 8 25

CALCIUM 1864 1648 1701 1942

MAGNESIUM 152 526 66 256

PHOSPHORUS 876 868 616 789

ZINC 1076 1054 737 952

BARIUM 0 0 2 1





SUS VIS 210ºF 65.6 66.2 59.3

cSt @ 212ºF 11.78 11.95 10.02

FLASHPOINT ºF 385 385 390

FUEL %
ANTIFREEZE % 0 0 0

WATER % 0 0 0

INSOLUBLES % 0.4 0.3 0.3

TBN 2.7 3.6 2.6

 

[addyguy]

Your Si, as you said, is still very, very high for the miles and is most likely contributing to the high wear metals. Aluminum, from the pistons is higher than normal and shows accelearated wear from dirt. You might want to look for air leaks in your intake system.

You're right, these aren't horrible results, and are well within acceptble limits. But for how picky we are on this site, most people know you can do better.

 

[El_Schaf]

I have to ask...does that thing haul? 5.7 grocery getter...that sounds FUN.

 

[NYSteve]

Yep, they haul as that 5.7 is a Corvette derived LT1. impalassforum.com for all the info you want on these great cars.

 

[WishIhadatruck]

They were pretty quick right from the factory (at least back then they would have been considered quite fast). I've left mine pretty much stock but many people at impalassforum.com make powertrain upgrades. Since the engine is so similar to the Corvette and Camaro engines there are lots of options. Changing the rear axle ratio is probably the biggest benefit since they are geared for fuel economy more than accleration. Most of the wagons had a 2.56:1 axle ratio unless you get the tow package (like mine) which have a 2.93:1 with a limited slip. I'd like to have a 3.42 or 3.73 ratio but it isn't in the budget right now and I'm not sure what it would do to my gas mileage either.

 

[dnewton3]

One thing I see that seems odd is how the TBN has dropped, in all three products. An HDEO oil should hold up better than that with only 5k miles on it.

And yet, the fuel and coolant and vis are well in control.

Just seems odd to me. I've seen HDEO oils in diesel engines run 10k miles, and have more TBN left than that.

I'd look for an air leak sucking in dirt somewhere, regarding the silicon, and probable subsequent wear metals.

 

[Rabbler]

What kind of oil leaks were fixed? If Silicone sealers (RTV) were used that is likely the source of the high Silicon.
My 3.4l returned triple digit Si after the intake gaskets were replaced.
Is that a CJ-4 spec Rotella? I would have expected higher Zinc and Phos from a HDEO. TBN is usually lower on CJ-4 oils too...

 

[WishIhadatruck]

The oil leaks fixed were the pan gasket, front main seal and some sensor. The earlier high silicone was definitely from the RTV but it seems like it would be lower by now.

Yes it is CJ-4.

 

[dnewton3]

CJ-4 Rotella starts at 10 TBN or something like that.

To drop to 2.7 in only 5k miles in a gasser seems extreme, to me. Again, I've seen diesel engines run more mileage (sometimes as much as 2x more) on CJ-4 and have more TBN left. Heck, even the gasser oils dropped down fairly quickly, so the HDEO didn't really fare any better than the gasser oils, in respect to TBN.

Just seems odd; that's a heck of a TBN drop in so few miles.

 

[RWEST]

Quote:
Just seems odd; that's a heck of a TBN drop in so few miles.
Yep!!