Motor Oil Analysis from Range Rover 4.6 Engines

This investigation was sparked by three primary things: I discovered varnish or sludge on our Rovers' dip sticks; a coworker swears by AMSOIL and Mobil 1 synthetic oils; and a friend thought that Royal Purple was the best and that AMSOIL was a "snake oil" pyramid scheme. So, I aim to find out which of these full synthetic oils is the best for our vehicles and if the full synthetic oils are actually better than the low-cost conventional Walmart and AutoZone oils that I have been using.

Erin bought her 2000 Land Rover Range Rover 4.6 HSE in March of 2007 on Saint Patrick's Day with 55000 miles on it. I bought my 2000 Land Rover Range Rover 4.6 Rhino on July 4th of 2007 with 55000 miles on it. I have been using Walmart or AutoZone 10W-40 conventional oil and STP oil filters from 55000-85000 miles on the HSE and from 55000-80000 on the Rhino. I changed the oil immediately after purchase and I have been changing the oil every 5000 miles even though the manual allows for a longer interval. Both vehicles have a black and brown coating of varnish or sludge on the dip sticks that seems to be getting worse over time.

I converted the HSE to AMSOIL on October 6 of 2009 at 85000 miles. I drained the old oil, took an oil sample, replaced the filter with another STP filter, and filled it with new AutoZone 10W-40 oil again. I added AMSOIL engine flush to the oil and ran the car between 1500rpm and 2000rpm for 20 minutes in neutral to clean out some of the crap built up in the engine. Then I drained the flush oil and replaced the STP filter with an AMSOIL oil filter. Then I filled it with AMSOIL 10W-40 and put a new air filter on. Finally, I put two 16-ounce cans of Sea Foam in the fuel tank and filled it with gasoline. It is running noticeably smoother now. I was really surprised, but I noticed a difference right away. Erin commented on it the next day when she drove it. Apparently you can use Sea Foam as an engine flush also, but I did not discover that until after I bought the AMSOIL engine flush.

I converted the Rhino to Royal Purple on November 25 of 2009 at 80000 miles. I drained the old oil, took an oil sample, replaced the filter with another STP filter, and filled it with new AutoZone 10W-40 oil again. I added AMSOIL engine flush to the oil and ran the car between 1500rpm and 2000rpm for 20 minutes in neutral to clean out some of the crap built up in the engine. Then I drained the flush oil and replaced the STP filter with an AMSOIL oil filter. Then I filled it with Royal Purple 10W-40 and put a new air filter on. Finally, I put two 16-ounce cans of Sea Foam in the fuel tank and filled it with gasoline. It is running noticeably smoother just like the HSE.

I used Mobil 1 and Castrol Syntec in subsequent oil changes to gather more data. Oil Analyzers Inc. performed all of the oil analysis for me. I bought the prepaid postage oil test kits through AMSOIL's website at the same time I bought AMSOIL oil and filters, which was very convenient. All of my samples listed the grade of oil, date, mileage, and unit, but not the lube manufacturer to guarantee unbiased test results.

The first thing to notice is the similarity between sample #1 for both engines. This first sample period used the same AutoZone lube for the same mileage to establish a meaningful baseline. Both samples show a 100C viscosity of 10.1, which indicates that the SAE 40 has degraded to an SAE 30. An SAE 40 oil should have viscosity between 12.5 and 16.3. In fact, all of the values are very close except for silicon contamination in the 4.6. The samples indicate that the engines are in very similar condition and performing in a similar manner. I should be able to compare oil samples from each vehicle with the exception of silicon contamination.

My conclusions are listed after the oil analysis results table.

Oil Analysis Results

severity
0	1	2	3	4
normal		abnormal		critical

general	unit id	Range Rover 4.6 HSE	Range Rover 4.6 HSE	Range Rover 4.6 HSE	Rhino Range Rover	Rhino Range Rover	Rhino Range Rover
	sample number	1	2	3	1	2	3
	date sampled	10/06/09	07/01/10	?	11/25/09	01/30/10	?
	date received	11/13/09	07/07/10	?	01/08/10	02/22/10	?
	unit time	85000	90000	95000	80000	85000	90000
	lube miles	5000	5000	5000	5000	5000	5000
	lube days	158	268		208	66
	miles/day	31.65	18.66		24.04	75.76
	lube brand	AutoZone	AMSOIL AMO	Mobil 1	AutoZone	Royal Purple	Castrol Syntec
	lube viscosity	10W-40	10W-40	10W-40	10W-40	10W-40	10W-40
	lube API spec	SL-SJ	SL-SG CI-4+ CH-4 CF CF-2	SL-SJ CF	SL-SJ	SL CG-4 CH-4 CI-4	SM-SH CF CD
	filter	STP	AMSOIL	AMSOIL	STP	AMSOIL	AMSOIL
	lube changed	y	y	y	y	y	y
	filter changed	y	y	y	y	y	y
	fuel est	<1%	<1%		<1%	<1%
	soot est	<.1%	<.1%		<.1%	<.1%
	water infrared	<.1%	<.1%		<.1%	<.1%
	vis 40C cst
	vis 100C cs	10.1	12.3		10.1	11.3
	tan total acid
	tbn total base	1.6	5.19		1.27	4.15
	i-r oxidation	14	46		13	15
	i-r nitration	21	22		22	22
	iso code
	4 micron
	6 micron
	10 micron
	14 micron
	21 micron
	38 micron
	70 micron
	100 micron
wear metals ppm	iron	13	25		24	12
	chromium	0	1		0	1
	nickel	0	0		0	0
	aluminum	8	7		5	3
	copper	11	12		14	5
	lead	4	1		4	2
	tin	6	5		6	1
	cadmium	0	0		0	0
	silver	0	0		0	0
	vanadium	0	0		0	0
	total	42	51	0	53	24	0
contaminant metals ppm	silicon	28	37		5	12
	sodium	2	7		5	7
	potassium	2	3		6	3
multi- source metals ppm	titanium	0	0		0	0
	molybdenum	25	10		47	77
	antimony	0	0		1	0
	manganese	0	0		0	0
	lithium	0	0		0	0
	boron	2	0		1	0
additive metals ppm	magnesium	8	11		7	7
	calcium	2013	3190		1663	2151
	barium	0	0		0	0
	phosphorous	714	1008		698	767
	zinc	813	1151		849	899

Conclusions

The Auto Zone conventional oil degraded and performs like an SAE 30 instead of an SAE 40 after 5000 miles, which means that protection is seriously reduced. The TBN is extremely low, which means that this oil is not capable of neutralizing much more acid and degradation would likely accelerate soon. The Royal Purple oil also degraded to below an SAE 40 viscosity, but not as bad as the conventional oil. Most of the wear metals are reduced compared to the conventional oil and the total wear metal count is about half, but the engine experienced more highway miles than normal during this period. The AMSOIL degraded to just below an SAE 40, but not as bad as the other oils. The TBN and additive metals were high and the "High Zinc Formula" they claim seems to be accurate. Unfortunately, the wear metals increased, but I think this is a result of the increased silicon contamination and fewer highway miles for this period.

Motor Oil Analysis from a Buell 1125 Engine

I really got curious about motorcycle oils after I started testing oils in the Rovers. I found some excellent background information on motorcycle oils: Sport Rider August 2003 Oils Well That Ends Well, Part 1, Sport Rider October 2003 Oils Well That Ends Well, Part 2, and AMSOIL June 2009 A Study of Motorcycle Oils Second Edition. Many of the oil test results match up between the two studies despite the 6 year difference. Also, AMSOIL does not win every one of the test categories in their study. Therefore, I think these two observations lend a lot of validity to the AMSOIL study and I am inclined to believe the published results about all of the oils tested in both studies. However, I want to independently test at least 2-3 oils that appear in the AMSOIL study to see how my real-world results compare.

I found another great article called All About Motor Oil. It covers many motor oil topics in great detail and the author strongly advocates using synthetic commercial-certified (Diesel) oils or conventional commercial-certified (Diesel) oils in motorcycles because of the additive packages and cost. The newest API standard (SM) oils are not necessarily good for high-performance motorcycle engines or older engine designs because of a shift in the additives allowed. I would argue that many of the motorcycle-specific motor oils are excellent and that a "Diesel" oil is not required. The author's goal seems to be finding the most cost effective protection and not necessarily finding the best protection that money can buy.

I broke the bike in according to the guidance in the owner's manual. It was torture, but I actually stayed under the RPM limits for the mileages specified. I was very happy after I did the first service and I could really unload on it. My conclusions are after the oil analysis results table.

Oil Analysis Results

severity
0	1	2	3	4
normal		abnormal		critical

general	unit id	2009 Buell 1125R	2009 Buell 1125R	2009 Buell 1125R	2009 Buell 1125R	2009 Buell 1125R	2009 Buell 1125R
	sample number	1	2	3	4	5	6
	date sampled	05/01/10	?	?	?	?	?
	date received	?	?	?	?	?	?
	unit time	3600	6600	9600	12600	15600	18600
	lube time	3000	3000	3000	3000	3000	3000
	lube brand	AMSOIL MCV	HD SYN3	Mobil 1 V-Twin	Red Line MC	Royal Purple MC	Castrol RS VT 4T
	lube viscosity	20W-50	20W-50	20W-50	20W-50	20W-50	20W-50
	lube spec	SL-SG CG-4 JASO MA/MA2		SJ-SG CF CD JASO MA	SJ-SG JASO MB		SJ JASO MA2
	filter	Buell	Buell	Buell	Buell	Buell	Buell
	lube changed	y	y	y	y	y	y
	filter changed	y	y	y	y	y	y
	fuel est
	soot est
	water infrared
	vis 40C cst
	vis 100C cs
	tan total acid
	tbn total base
	i-r oxidation
	i-r nitration
	iso code
	4 micron
	6 micron
	10 micron
	14 micron
	21 micron
	38 micron
	70 micron
	100 micron
wear metals ppm	iron
	chromium
	nickel
	aluminum
	copper
	lead
	tin
	cadmium
	silver
	vanadium
	total	0	0	0	0	0	0
contaminant metals ppm	silicon
	sodium
	potassium
multi- source metals ppm	titanium
	molybdenum
	antimony
	manganese
	lithium
	boron
additive metals ppm	magnesium
	calcium
	barium
	phosphorous
	zinc