Shell Rotella Syn 5w-40 in 1991 BMW 318i

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JHZR2

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These are my results from my BMW. The last two UOAs have been continuous, with Shell Rotella Synthetic 5w-40 being used. I have used LC at the 10z/qt rate and then ~2oz/1000mi. Ive also used FP at 2oz/10 gal, though a few things should be noted that are important: -I used MMO a few times during this OCI, once at a very high shock dose where I got low MPG as a result (It was about 8 or so oz. per 10 gal). -In the last 1200 miles, I added a bottle of Auto-rx for cleaning. The car appeared to idle a bit better than it did previously, but there was no MPG improvement or anything else. I did not add LC when I had the ARx in the crankcase, though residual was likely still there. The car passes HC/CO/CO2 emissions fine, but fails NOx on the NJ dyno test. I get 27-29 MPG regularly, in mixed driving. The oil that was in the car during the last emissions test was the previous rotella OCI, where the results were quite good. Id guess that either there was some significant problem with ARX and LC in combination, resulting in the reduced viscosity and increased wear numbers. It should also be noted that in the gap between the older two OCIs and the two rotella OCIs, the same rotella Syn oil was used, so viscosity retention was not a function of remaining 15w-50 M1 in the crankcase. I find the oxidation number odd (I copied this right off of the website with my results. Nitration seems normal, though higher than last time, when LC was used the entire interval. Sulfation is also higher than normal, though I cant say what that means. I have to wonder if the MMO used caused the viscosity drop... Especially since it has been tested againa and again that LC and ARX do not effect viscosity. I wish I had a fuel dilution number, as that might give some insight, but the car runs the same, and the use profile has been the same, so I dont see a reason why in summertime driving, fuel dilution would have gone up...
code:
  Sample Date	9/14/2005	6/28/2005	4/10/2004	7/10/2003
 Unit Age	101039m	97679	91572m	87249m
 Time on Fluid	3360m	3793m	2804m	2972m
 Time on Filter	3360m	3793m	2804m	500m
 Fluid Maint.	Changed	Changed	Changed	Changed
 Filter Maint.	Changed	Changed	Changed	Changed
 Fluid	       RtS 5-40 RtS5-40 M1 1550 PzLL 15w-40
 Iron (Fe)	12	7	16	22
 Chromium (Cr)	0.9	0.6	1.4	1.3
 Nickel (Ni)	0.5	0.9	1.4	0
 Titanium (Ti)	0.1	0.2	0	0.3
 Silver (Ag)	0	0	0	0
 Aluminum (Al)	1.6	1.5	3.2	5.5
 Lead (Pb)	1.7	2.1	3.6	1.9
 Copper (Cu)	3.9	2.8	2	1.5
 Tin (Sn)	0	0	0.1	0
 Silicon (Si)	1.9	4	12	7.1
 Sodium (Na)	2.9	3.5	0.7	3.4
 Potassium (K)	0.1	11	3.3	0
 Boron (B)	5.5	9.9	198	140
 Barium (Ba)	0.3	1.4	0	0
 Molybdenum (Mo)1.9	4.3	80	123
 Magnesium (Mg)	12	33	19	13
 Calcium (Ca)	2684	2964	3212	3990
 Phosphorus (P)	990	974	919	1352
 Zinc (Zn)	1082	1011	1014	1523
 Sulfur (S)	3950	4025	2118	4350
 Cadmium (Cd)	0	0	0	0
 Manganese (Mn)	0.6	1.2	1.2	0.3
 Vanadium (V)	0	0	0	0
 Soot(%)	0	0	0	0
 Oxidation(PA)	345	95	n/a	45
 Nitratrion(PA)	40	25	n/a	40
 Sulfation(PA)	77	17	57	27
 ZDDP	        -0.06	0	0	-0.02
 [email protected]°C	12.64	13.05	13.33	13.94
 White Metal	NONE	NONE	NONE	NONE
 Babbitt	NONE	NONE	NONE	NONE
 Precipitate	NONE	NONE	NONE	NONE
 Silt	        NONE	NONE	NONE	NONE
 Debris	        NONE	NONE	NONE	NONE
 Dirt	        NONE	NONE	NONE	NONE
 Appearance	NORML	NORML	NORML	NORML
 Odor	        NORML	NORML	NORML	NORML
 H2O(Emul)	NEG	NEG	NEG	NEG
 H2O(Free)	NEG	NEG	NEG	NEG
 

 

Al

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Elizabethtown, Pa
Nice results. Sure looks like you could go further. Don't know what to make of the Oxidation. Looking at the Nit..the Oxidation # is either wrong or the MMO might have done it. That's hard to believe though.
 

JHZR2

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Im not really worried about the oxidation number... if the oil was oxidized badly, wouldnt it have thickened quite a bit? I'm concerned about the combo of MMO, ARx, LC and FP, some interaction which must have effected the viscoisty. Granted, the 15w-50 M1 run looks a little low in viscosity, but this engine isnt really hard on the oil. Thanks, JMH
 

Al

Joined
Jun 8, 2002
Messages
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Location
Elizabethtown, Pa
quote:
Originally posted by JHZR2: I'm concerned about the combo of MMO, ARx, LC and FP, some interaction which must have effected the viscoisty.
I would be a bit leary of that also. I'm not sure oxidation will always thicken oil in the initial stages. I think that the classic oxidation that is seen is thiking of the oil in ther terminal stages. I could be wrong though.
 
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