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Oil Analysis as a part of your marine survey Is it worth the money ?
Absolutely Yes ! ........... maybe not !
Oil analysis is a testing program used to monitor lubricating oils in order to determine wear of metal components. This is not limited to engines but can also highlight potential problems with gear reduction units, hydraulic systems and fuel.

Like so much else in boating this ain't rocket science. Go to your local auto parts store, UAP/NAPA, Cawthra Automotive etc. and ask for an oil analysis kit. They will charge you 30-40 bucks and it will come with all instructions and a pre-paid envelope to mail your sample to the lab but read the rest of this before you run out the door. Once you receive the report you may want to buy your favourite mechanic a beer while he translates it for you. Look at it this way, you can afford the beer 'cause you didn't have to pay him $100.00 to pick up the kit from the autoparts store and draw the sample. The kit will provide you with instructions, a container for the oil and a questionaire that will ask the brand, weight, hours on oil, make and model of engine, engine hours and a few other basic questions. some kits even supply a tube and plastic bellows type pump to draw the oil through the dipstick tube.

Its not pertinent but I like to have photos of boats in my articles
so here is a shot of the Nordica 20 sailboat my mechanic
buddy Robert Wainwright is turning in to a mini-tug
Once supplied with the sample most labs will send you a report within the week. For the analysis to be of value you must answer all the questions on the questionaire. The lab must know what oil is in the engine as all have proprietary additives that affect the chemical analysis, so the lab must have some baseline information to begin with. How long has the oil been in the engine and how many hours are on it ? Every report will show some contamination but unless you know how much abuse the oil has taken, how can you know if the contamination is normal or excessive ? It's also important to run the engine up to temperature before drawing the samples as this ensures any contaminants will be in suspension and give much more accurate reading.

If you are purchasing a boat that has not been used this year or since its last oil change, an analysis will tell you absolutely nothing as the oil has not had a chance to accumulate contaminants. If you draw your sample from the bottom of the oil pan on a boat that has not been used in some time the results may be unfairly pessimistic as the contaminants will have settled to the bottom. If you draw the sample from near the top of the oil pan an overly positive report may result.

Even a highly qualified mechanic may not be able to tell you much from a one-off test except for catastrophic conditions which would likely be noticed under normal sea trial conditions anyway.

A proper diesel engine survey including injector inspection and compression tests cost much more than a gasoline engine. A good diesel mechanic can tell a lot about a diesel engine just by looking at it and running it under load. It's up to you ..... you pays your money and takes your chances.

The perfect analysis ..... Use the same brand and weight of oil .... always. Try to stick with the same source for your testing because report style and content can vary. Take the sample at the same time of year every year and try to take the samples with the same number of running hours on the engine every year.

You may have noticed that I underlined the word program. I did this to emphasize that oil analysis should be a routine part of your maintenance program and not just a one-off when you are buying a used boat. If you do an annual oil analysis with a proper log of oil type and usage you would have a very accurate picture of the condition of your engine within a few test cycles. For most pleasure craft this would mean an annual test at end of season before the oil is changed. It would be pointless to send fresh oil or oil with only a few hours on it to the lab. Building a history of oil contaminants and the hours it takes them to accumulate to a given level can provide warranty protection on a new boat and a useful early warning system of potential problems from valves, rings, pistons, cylinders, bushings, rods, camshafts etc. As all of these components are made up of various alloys it can be quite easy to identify a specific part that is degrading faster than we'd like. Among the contaminants accounted for in the analysis are water, glycol, sulfur, soot and a number of metals such as those listed below.

Iron (Fe) Indicates wear originating from rings, shafts, gears, valve train, cylinder walls, and pistons in some engines.
Nickel (Ni) Secondary indicator of wear from certain types of bearings, shafts, valves and valve guides.
Molybdenum (Mo) Indicates ring wear. Used as an additive in some oils.
Chromium (Cu) Primary sources are chromed parts such as rings, liners, etc., and some coolant additives.
Aluminum (Al) Indicates wear of pistons, rod bearings and certain types of bushings.
Tin (Sn) Indicates wear from bearings when babbitt overlays are used. Also and indicator of piston wear in some engines.
Silver (Ag) Wear of bearings which contain silver. In some instances, a secondary indicator of oil cooler problems, especially when coolant in sample is detected.
Copper (Cu) Wear from bearings, rocker arm bushings, wrist pin bushings, thrust washers, other bronze and brass parts. In some transmissions, wear from discs and clutch plates. Oil additive or anti-seize compound.
Sodium (Na) Coolant additive; used as an additive in some oils.
Silicon (Si) A measure of airborne dust and dirt contamination, usually indicating improper air cleaner service. Excessive dirt and abrasives can greatly accelerate component wear.
Boron (B) Coolant additive; used as an additive in some oils.
Phosphorous (P) Antitrust agents, spark-plug and combustion chamber deposit reducers.
Zinc (Zn) Antioxidants, corrosion inhibitors, anti-wear additives, detergents, extreme pressure additives.
Calcium (Ca) Detergents, dispersants, acid neutralizers.
Barbium (BA) Corrosion inhibitors, detergents, rust inhibitors.
Magnesium (Mg) Dispersant - detergent additive, alloying metal.

For those who have not seen an oil analysis report, this 11 page one includes analysis of generator oil, both engines and the lube from both gear reduction units. This report is pretty typical and clearly shows why you may need to hire a qualified diesel mechanic to help interpret.





So you may save the cost and time of an oil analysis by simply pulling the dipstick and taking a look.
The first photo at right shows an engine with potentially costly issues. The second dipstick is a financial disaster.

Below I have copied (unedited) a response to a discussion of oil analysis on
Trawler Forum. This fella knows his stuff and I asked his permission to add his thoughts here. I can't find a single thing in his missive that I disagree with
Water beads on dipstick
Mud, water and corrosion on dipstick
stone beach
Trawler Forum Member

City: Geoje
Country: South Korea
Vessel Model: Boston Whaler 31L
Join Date: Feb 2014
Posts: 19
boat poker, its a good article.

Cards on the table, I have more than 50 years in marine engineering and in that time have had many thousands of oil analysis reports across my desk.
Oil analysis definitely has a place in the industry, can be a useful tool, can provide forensic data and has applications within condition assessments and maintenace regimes.

History lesson, jump this paragraph if you are in a hurry! The process was originally created for large systems, you simply can not throw away large quantities of expensive material based on xx hours in operation, rather you sample it and determine the oil's suitablity for further use and what treatment may be required to ensure that suitability continues. Originally it covered only the basic properties, viscosity, TBN etc, still its most important use in my view. This was expanded to include wear materials (by spectographic examination) when the equipment became readily available, reasonably sized and at reasonable costs and as a kind of added service offered by the oil suppliers to differentiate themselves, thus it was essentially a marketing move for a process that was technically available at low cost. For such a process to deliver reliable results the laboratory must perform to the required quality standard AND the sample must be drawn in a controlled and repeatable manner. In such a situation the results can be trended and over time can become useful. Later, people realised it was a product / service they could sell and now it is generally available.

In engines and other systems of the size that are addressed by this forum, I believe that frequent oil changes provide absolutely the most cost effective maintenance possible, sampling provides very little for the money in real terms, the money is better spent on the oil

I dont think any of these "small" engines are adequately equipped to draw a sample in the controlled manner required (as standard) and whilst taking an oil sample from the sump or wherever may provide some added interest (and certainly in itself it does no harm) I dont actually think it does much good, it's akin to the car enthusiast polishing his car every week, it doesnt hurt it but neither does it improve any measurable parameter of the vehicle.

Value of the analysis, just like you would not expect an MD to give you a (medical) diagnosis based solely on your pulse rate, anyone who is giving a diagnosis based solely on an oil analysis is kidding you. Together with other information spectographic analysis can help with a diagnosis, but it is unlikely and it is certainly beyond the scope of "normal" mechanics. As part of a test and trial process a lead mechanic should be able to draw some conclusion which an oil analysis may reinforce but he would have probably got there anyway with the other tools at his disposal

Of the thousands of reports I have dealt with I can't remember one which saved us from a failure, although I can remember a few instances where this may have been the case had the results been returned and reviewed quickly enough. In these few cases they merely helped us in a forensic sense to understand the origin of the failure, sometimes this is not as simple as it may sound when all you have is a large pile of scrap !!

So, as always, its your boat, your money and your hobby and if taking samples adds interest it certainly does no harm in itself. The harm comes from the "quack" diagnostician who leads you to waste more money.

stone beach is offline

One last point. I was recently involved in a case where three samples from the same engine were sent to a lab and got back three distinctly different reports. Not all labs or mechanics are created equal.

An equivalent analysis may also be performed on fuel, coolant, gear reduction fluid and even hydraulic fluid. On a large trawler type boat with a full load of diesel this may amount to several thousand dollars worth of fuel. If you are buying such a boat it may be a wise investment as bad fuel is the most common reason for diesels shutting down.