This preventative maintenance tool brings to mind the adage that “an ounce of prevention is worth a pound of cure.”
By Bill Hendrix, F761S
March 2005
We all have heard stories about the coach owner who did all the maintenance per the recommended schedule, watched the temperature gauges, and yet the engine blew with disastrous results. How can this be? Could it possibly be a defective part, improperly torqued bolts, or manufacturing contamination? Who knows, but it happens. Being stranded on the side of the highway with oil running everywhere really is an unpleasant scene. Spending days in a shop while you are supposed to be traveling is not fun and is very stressful. You may be fortunate enough that your engine is within the warranty period, but it still would be a hassle. If out of warranty, this could be a budget-busting expenditure that leaves you with no viable options. Could this have been prevented? Would an oil analysis program have given sufficient warning? Let’s take a look at a super preventative maintenance tool.
An oil analysis is a very thorough examination of an oil or lubricant done by a specialty lab qualified to make a spectrochemical analysis. This type of analysis can determine component wear, the presence of contaminants, and oil additive concentrations. Oil sampling may be done at any regular or irregular interval, but most commonly individuals will take the sample during the oil change. The vast majority of diesel engine shops make this service available, and a handful of the larger engine shops have an in-house lab that can give super-fast results by eliminating the mailing time.
Many of the independent labs analyze all kinds of lubricants, greases, and antifreeze. Most are geared to fleet maintenance but will be glad to provide analysis for individuals also. Ballpark cost is mostly between $15 and $30 per sample. Some labs may give a price break on a 10- or 12-quantity purchase. You get a sample bottle for a few ounces of oil, an information sheet to fill out for the lab, and a container for shipping. Most will mail the results in a few days, some will fax upon request, and some will call if there are immediate concerns.
Oil analysis reports typically are divided into four categories, the first three expressed in parts per million (ppm): 1. Wear Metals, 2. Contaminants, 3. Additives, 4. Physical Properties.
1. Wear Metals Commonly From
Iron Cylinders, Gears, Rings, Crankshaft, Liners, Bearings, Rust Below 100 ppm is very good
Chromium Rings, Roller and Taper Bearings, Rods, Chrome Plating Single digit is very good
Lead Bearing Overlays, Oil and Gasoline Additives Single digit is very good
Copper Bearings, Bushings, Pistons, Thrust-Washers, Oil Additive Single digit is very good
Tin Bearings, Bushings, Pistons, Plating Under 6 ppm is desirable
Aluminum Bearings, Pistons, Thrust-Washers, Pumps, Blowers Under 6 ppm desirable
Nickel Valves These should be zero or near zero
Silver Bearings, Bushings, Plating These should be zero or near zero
Manganese Additive in Gasoline, Trace Element in Liners and Rings These should be zero or near zero
Titanium Trace Element These should be zero or near zero
Vanadium Trace Element These should be zero or near zero
The above group can reveal inordinate wear of critical moving parts. A new engine will show higher wear figures during the break-in period, and then a normal wear pattern can be expected. The engine is considered broken in when the wear numbers decline to normal levels. The break-in period for gasoline engines would be 3,000 to 6,000 miles (60 to 120 hours); for diesel, 12,000 to 35,000 miles (240 to 700 hours).
2. Contaminants Common Source
Silicon Airborne dirt (may be an oil additive for anti-foaming)
Boron Antifreeze (may be an oil additive)
Sodium Antifreeze (may be an oil additive)
Potassium Antifreeze (may be a gear oil additive)
The information sheet you supply with the oil sample tells the lab what kind and type of oil it is. They will know what additives are germane to that particular oil.
3. Additives For
Magnesium Dispersant/Detergent
Calcium Dispersant/Detergent
Barium Dispersant/Detergent
Phosphorus Anti-wear
Zinc Anti-wear
Molybdenum Anti-wear
These are elements present in the oil’s formulation, and the results of the analysis are useful to commercial operators wanting to extend oil life to the maximum.
4. Physical Properties (Not in ppm)
| Water | In Percentage “” possibly from condensation | Zero is good |
| Glycol | Positive or negative for antifreeze leaking into oil | If this shows negative, any boron and/or sodium would then be from an oil formulation additive |
| Fuel | In Percentage “” Incomplete combustion or long idling | Ideally less than 1% but less than 2% okay |
| Soot | In Percentage “” Incomplete combustion or blow-by | Always present in diesel but ideally below 1% |
| Viscosity | Checks the oil viscosity after used | Can indicate the oil is breaking down |
This is a lot of information to digest, but the good news is that you don’t have to go to school and learn to read the statistics. With the information you give along with the sample, minimum and maximum values will be assigned for each item. If a number falls outside the window, it will be given a notation of either “Abnormal” or “Critical” and probably some comment as to the cause will be included. You may refer to the reference data, which often appears on the back of the report, and draw your own conclusion for corrective action.
If the report indicated “Critical” on lead, copper, and tin, one might suspect excessive bearing wear. If there is a high number on silicon, look for a breach in the air intake tubes or the air filter. If any abnormal or critical notations were made, the most prudent course of action would be to take the report to your mechanic or the engine shop and ask for a consultation. After two or three samples, most labs will graph a few of the more pertinent elements to show wear trends at a glance. If you are using reconstituted (re-refined or recycled) oil, ask for a total acid number (TAN) test to be sure the acidity is proper.
Analysis may also be performed on the generator, transmission, differential, power steering, oil bath wheel bearings, fan drive gearbox, and virtually anything using oil, as well as the engine coolant. Personally, I haven’t done anything beyond the engine oil and just follow the manufacturer’s recommendations for fluid change intervals for everything.
Is there a reason to do oil analysis if the engine is under warranty? Well, yes and no. No, it isn’t necessary, but, yes, it’s helpful if you can document a problem prior to the expiration of the warranty and attempt to have the problem corrected under warranty. You also can establish a baseline while in warranty for wear metals that will carry you into the non-warranty period with confidence.
The oil sample should be taken with the engine warm, in the middle of the drain if during an oil change. Sample extracting pumps are available for non-oil-change sampling of the engine and various other components. If you are interested in an oil change program, visit your local engine shop and see what their plan entails. You may also go to the Web and search “Oil Analysis” and there you will find a number of Internet sites, including CTC, Amsoil, and Blackstone. Some of these sites have FAQ pages with lots of information.
If you are price shopping, be sure to ask exactly what the analysis will include. A bare minimum should be the wear metals, physical properties, and silicon. Consider using the service recommended or sold by your local mechanic or engine shop. They will be more inclined to help you with questions you may have regarding the analysis.
Another side benefit from an ongoing analysis program would be having excellent documentation when it comes time to sell the coach. One of the biggest concerns of buying a used motorhome is the exposure for an engine failure. An analysis history is a very persuasive tool for both the seller and the buyer.
Analysis isn’t for every coach owner, but too often an ounce of prevention is worth a pound of cure.