Most of us get some kind of physical once every year or so – even if we think we’re healthy, it’s nice to have a doctor confirm our condition. Usually there is a blood panel done to check on nasty stuff like cholesterol.
When was the last time you checked the “life bloods” of your motorhome? I’m talking about the oil and lubricants that keep your engine, transmission and differential alive, as well as your engine’s coolant. If you live where temperatures never go below freezing, you might think the coolant or antifreeze in your engine aren’t a concern. That is a major mistake.
Sure you look at the radiator’s overflow tank and pull the dipsticks out now and then, but you have no way of knowing what you’re looking at, or what’s really going on inside, any more than checking your pulse and blood pressure can tell you the whole story. Is your drivetrain really healthy?
There is a way to find out, and it’s surprisingly easy and affordable without tearing things apart. We used our 1999 Ford F-550 motorhome as a guinea pig. We contacted Oil Analyzers Inc. and Polaris Laboratories, two companies we found to be the most helpful of those we contacted. They sent us nifty little sample jars (a jar in a jar for no leak worries) and special forms to identify the parameters.
Source, type of lubricant or coolant, miles or time in use, etc., are all needed by the tribologists and lab technicians. (Tribology is “the science of the mechanisms of friction, lubrication and wear of interacting surfaces that are in relative motion.”)
Taking a sample from the engine after it has been brought up to operating temperature can be tricky and messy. The dirty way is to sneak a little with a jar while you drain the oil. An easier way is to use the Femco No-Spill System, which uses an adapter in the oil pan and a drain tube that opens up a valve to allow all or just a little oil to flow out. No drips. No mess. No oil running down your arm.
Still cleaner, we used an Oil Analysis Pump Kit (Part #G-1206) from Amsoil; it’s a long tube that is inserted down the dipstick tube (engine or transmission). Oil or ATF is pumped directly into the test jar. The same kit can be used for any gearbox that has a fill plug, like a differential, all without even getting your hands dirty. A test jar screws onto the pump’s outlet. The kit comes with instructions for how to measure the correct length of tubing.
We took the opportunity in researching this article to test our Power Stroke engine, differentials, transmission and transfer case. While most motorhomes are not four-wheel drive, and most have automatic transmissions, the procedure is the same.
A typical spectrochemical analysis checks for iron, chromium, nickel, aluminum, copper, lead, tin, cadmium, silver, vanadium, sodium, potassium, titanium, molybdenum, antimony, manganese, lithium, boron, magnesium, calcium, barium, phosphorous and zinc, all measured in parts per million (ppm) by weight. Additionally, they check viscosity, and look for soot, water, fuel and acid.
Our 7.3-l Power Stroke came back with a clean bill of health, with 115,000 miles on it at the time the samples were taken. We liked the easy-to-read reports from Oil Analyzers, which uses a colored number code from 0 to 4 (red). Red (4) is “critical.” There are also written comments with each sample analyzed.
The Ford ZF six-speed manual transmission and the factory transfer case were both red-tagged “4” critical, with high levels of aluminum, a possible indication of gear or bearing wear, bushing and thrust metal, alumina silica (dirt), housing metal, or contamination from aluminum complex grease. There was also an abnormal level of manganese, 114 ppm. Obviously we were concerned. We contacted Dave Tingey, field services engineer at Oil Analyzers, for his opinion.
He told us that the high levels of aluminum found in our transmission and transfer case might be coming from the housings. They were flagged because the levels were significantly higher than what they would expect from a ZF-6 transmission. Manganese is usually a steel alloy found in gears. He recommended an analytical ferrograph to determine if these levels of aluminum were actually an indication of wear, or the possibility that they were just aluminum oxides, which are basically sub-micron and are not normally serious.
In performing an analytical ferrograph, the oil sample is run over a glass slide and there is a magnet that captures all the ferrous particles and lines them up on the slide. Since aluminum is non-ferrous you would think this would not show up on the slide, but there are usually enough ferrous particles generated in most equipment that the non-ferrous particles, including dirt, can be trapped and seen.
They then view the glass slide under a microscope and the analyst can see the type of material in question. When he knows the type of material and the unit type (transmission/engine), he can make the determination of whether the aluminum in the sample is from actual wear, or if the lack of aluminum on the slide indicates it’s just aluminum oxides, and probably not a problem.
To give us an idea of the size of the spectral-wear metals that are in the report, he said they are usually 10 microns. Anything smaller can normally only be seen with a microscope. For comparison, a human blood cell averages 3 to 6 microns.
Coolant is as critical to the proper function of any engine as oil, but especially diesels. The new engines introduced in the last few years are designed to lower fuel consumption and meet impending federal emission laws. As a result, the cooling systems for these new designs must operate at much higher temperatures. This makes careful cooling system maintenance necessary to avoid engine damage. Improper mixtures of antifreeze can cause corrosion, rust and overheating.
Specifically for diesel engines, there is a danger of cylinder cavitation or pitting. According to www.TheDieselStop.com, this is a localized low-pressure zone that forms adjacent to the outer wall of the cylinder. It is caused by the flexing of the cylinder wall due to the high cylinder pressures experienced in diesel engine ignition. This fast cylinder wall movement causes a low-pressure zone to be created in the coolant adjacent to the cylinder wall. When this pressure zone drops below the vapor pressure point (temperature, coolant ratio and additive dependent), a vapor bubble is formed. When this low-pressure zone returns to a high-pressure zone, the vapor bubble collapses, causing an implosion or pitting phenomenon on the cylinder wall, (like hitting the surface with a microscopic ball peen hammer). If left unchecked, pits can turn into little pinholes, and that’s an engine’s death sentence.
The proper mixture of water to antifreeze (50/50 is recommended as a starting point) not only protects the engine from freezing, it also raises the boiling point. That’s very important in today’s high-tech engines.
There are two types of antifreeze commonly available, propylene glycol and ethylene glycol. Ethylene glycol is considered to be highly toxic – a poison. Its alternative, propylene glycol, is a colorless, odorless liquid, which is generally recognized as safe by the U.S. Food and Drug Administration. In addition to antifreeze, coolants and aircraft de-icing fluids, it is also used in foods, fragrances, cosmetics and personal care products.
Propylene glycol is slightly less effective at lowering the freeze point, so a little higher concentration must be used in extreme locations, like Alaska. However, for normal use, it has a higher heat transfer efficiency. That’s an advantage when you’re lugging up a long, hot pass, and signs warn, “Turn air conditioner off – next eight miles.”
By now, you should be wondering how you can tell what’s in your cooling system. There are three important ways to test. A refractometer can be used to determine the freeze point protection for ethylene glycol and propylene glycol. By placing a drop of your coolant on the refractometer’s viewing plate, after first calibrating it with distilled water, and using the internal scale, you can calculate the freezing temperature. For example, a 52 percent concentration of propylene glycol will bring your protection point down to minus 50?F, colder than most of us will ever see.
To prevent cavitation, a diesel engine’s coolant should be checked at regular intervals with a test kit such as the Fleetguard CC2607 Quik-Chek or the Polaris four-part test strips. By simply dipping one of these test strips into your coolant and reading the chart, it will tell you the freeze point and the concentration of molybdate and nitrite, which in turn will determine the number of supplemental coolant additive (SCA) units per gallon in the system. The Polaris strips also measure pH. With this knowledge, you can add the appropriate amount of additive, antifreeze or distilled water to bring the coolant back up to a safe level.
Fleetguard’s DCA4 additive protects against corrosion, scale formation, foam, liner pitting and solder bloom.
A third method of testing, and perhaps the best, is to have your coolant analyzed by a professional lab. A turkey baster works well for taking a sample. Polaris offers a small syringe kit specifically for this purpose. We sent a sample from our Power Stroke engine to Polaris Laboratories. The results were very informative.
Our coolant showed a high level of sulfates, 461 ppm, and an SCA level of 6.1. The recommended level is 3.2 units per gallon. Our antifreeze was only 44 percent, which would protect us down to minus 13?F, but reduced our boiling point to a relative low 222?F. Nitrites were high, at 4,123 ppm, which may cause a precipitant problem. In our case, the imbalance could be easily corrected by adding a little Fleetguard propylene glycol concentrate.
According to Polaris, if the proper level of SCA is not maintained on a regular basis, every 15F to 17F increase in cooling system operating temperature above 160F can result in a potential doubling of deposits or acid pitting of metal for the same coolant problem, in the same amount of time, with the same rate of flow. (See examples below.)
Having the lubricants and coolant in your motorhome’s drivetrain tested periodically can save you a lot of money in the long run. For example, you may find that your oil doesn’t really need changing, and with the price of quality synthetic oils and lubricants, that’s a money saver in itself. Given the importance of your engine’s cooling system, keeping tabs on its concentration and level of SCA is equally important.
Dave Tingey advised us that “trending” analysis is best used for both lubricants and coolants. When a problem starts, it’s usually small. If you trend the fluids and the levels of wear increase, you can often fix the problem before it reaches catastrophic proportions. Trending is sort of like getting a blood panel done when you’re 50 for a base line, and checking it again in a year to see if anything has changed. High cholesterol? Just add a few units of Fleetguard’s DCA4, or maybe Lipitor might work better.
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