DIESEL USED LUBE OIL ANALYSIS GUIDE TO LUBE OIL CONDITIONS
1982-1985 C, K, G, P, D - 1, 2, 3 WITH 6.2L DIESEL ENGINE
This bulletin is being issued to provide information for 6.2L diesel engine used lube oil analysis warning values and used lube oil analysis guide- lines. Whenever the user performs a used lube oil analysis, it is important to note that the analysis charts are a guide to the condition of the lube oil and will not necessarily reflect the condition of an engine.
OIL AND FILTER RECOMMENDATIONS
Oil and filter change intervals are critical to the performance and durability of the 6.2L diesel engine. Consult the Owner's and Driver's Manual for the correct grade, viscosity, and oil change intervals.
It is important that each specific vehicle, based on the guidelines found in the Owner's Manual/Maintenance Schedule, adhere to the recommendations regarding oil grade, viscosity, and oil and filter change intervals that most closely describe the vehide's particular environment. Damage resulting from failure to do so is not covered by warranty.
USED LUBE OIL ANALYSIS PROGRAM
A used lube oil analysis program can be usefull in tracking the condition of the engine lube oil. However, it must be noted that a used lube oil analysis will only result in an INDICATION of the condition of the engine after several analyses have been performed over a regularly scheduled interval, and comparison of the results suggests a pattern or abnormality.
NOTICE: An engine SHOULD NEVER be disassembled based solely on the results of a SINGLE oil sample analysis.
Abnormal concentrations of some contaminants such as diesel fuel, glycol (engine coolant), road salt, or airborne dirt cannot be tolerated for long periods in the lube oil. The presence of these contaminants can cause accelerated engine wear and/or deposit accumulation which could reduce engine life. The lube oil should be changed immediately if any contamination exceeds the warning limits given in this bulletin.
Experience with specific engine applications is necessary to properly interpret any used lube oil sample analysis results. In evaluating used lube oil sample results, it is the change in value or deviation from the baseline data obtained from the new (unused) oil, that is important (same brand or mixture of brands).
FREQUENCY OF LUBE OIL SAMPLES FOR ANALYSIS
In order to obtain useful results from any lube oil analysis, it is imperative that the sample be taken at regular scheduled intervals. This enables like periods of time and mileage to be compared between samples and will result in a more useful indicator of the trending conditions of the engine.
6.2 LITER ENGINE USED LUBE OIL ANALYSIS WARNING VALUES
Wear Metal and/or Coolant Elements Limit (PPM) Footnotes -------- ------------ ---------- Iron 500 (A)
Copper 400 (150)* (A)(B)(D)
Lead 115 (A)
Molybdenum 40 (A)(B)
Aluminum 50
Tin 90
Silicon 90 (A)(B)(C)
Chrome 45
Sodium 50 (A)(B)
Boron 20 (A)(B)
(A) Values allowed over lube oil baseline.
(B) These elements may be present in the new lube oil or coolant additive package.
(C) This value can be high on a new engine or a recently serviced engine due to "Silicone" form-in-place gaskets.
(D) Engine(s) used in applications where extended idling is required may incur copper content levels up to 600/PPM.
* Lower value with 1985 model year engines because of revised rocker arm design.
6.2 LITER ENGINE CHEMICAL ANALYSIS USED LUBE OIL ANALYSIS GUIDELINES
ASTM Designation Warning Limits ----------- ---------------
Pentane Insolubles, Wt. % D-893 1.00
Carbon (Soot) Content Wt. % Max. TGA+ 2.00
Viscosity at 40 DEG C, CST. D-445 % Max. Increase 40.0 % Max. Decrease 15.0
Total Base Number (TBN), Min. D-664 1.00
Total Base Number (TBN), Min. D-2896 2.00
Water Content (Dilution), Vol. %, Max. D-85 0.30
Flash Point, of Max. Reduction D-92 40.0
Fuel Dilution, Vol. %, Max. - 2.50
Glycol Dilution, PPM., Max. D-2982 1000.00
+TGA = Thermogravimetric analysis used and recommended by Detroit Diesel. No ASTM procedure designation.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
