Mercedes calls their unit a “Flexible Service System”. The FSS on some Mercedes vehicles monitors actual oil quality as well as operating conditions (such as the number of cold starts, average engine temp, mileage driven, oil sump level, rpms, etc.). To measure oil quality, there is actually a sensor that measures the electrical conductivity of the oil. The higher the conductivity of the oil, the greater the need for an oil change, according to Mercedes. Of course, this isn’t likely a perfect model, and will not be nearly as accurate as an actual oil analysis in determining true oil quality, but it is better than no measurement at all.
At any rate, as electrical conductivity increases, this value is combined with all of the operating condition data and run through a special algorithm to determine if the oil is ready for a change. When a change is necessary, a light will flash on the instrument panel indicating such.
The other Mercedes FSS unit, which will be somewhat less accurate, does not actually measure the electrical conductivity of the oil, so it is not testing the quality of the oil in any way. It does, however, measure all of the operating conditions and uses the algorithm to predict when an oil change will be necessary.
This is actually how the GM oil monitoring system works. It does not measure oil quality via electrical conductivity or via any other means. It simply measures operating conditions and “calculates” when an oil change should be necessary based upon those conditions.
So, How Accurate Are These Units? Can They Be Trusted?
That’s a tough question to answer at this point. First off, these systems haven’t been in use long enough to really have much in the way of hard statistics comparing vehicle/engine life with or without these systems in place. Second, many drivers do not trust the longer drain intervals recommended by these units and change the oil sooner anyway, offering, again, little data to show whether the drain intervals recommended by these systems are conservative enough to maintain engine protection equal to that attained with shorter change intervals.
Since these units do not FULLY measure oil quality, in the same way that an actual oil analysis would, it is unlikely that they are completely accurate, but there is good reason to believe that they are fairly accurate.
The problem, from my perspective is, how were the limits set? Quite frankly, it’s in the best interests of vehicle manufacturers to have their engines begin to decline in performance somewhere shortly after the 100,000 mile marker. Many people these days don’t expect a vehicle to perform well much beyond 100K, so building a vehicle and recommending maintenance practices that will help the vehicle perform longer than that is not in the best interest of the OEMs.
So, I would be willing to bet that, if you are an individual that likes to keep your vehicle as long as possible, oil quality limits have been set to a lower standard than would be appropriate to getting the absolute most mileage from your vehicle. It really only stands to reason.
How many companies do you know of these days that build MORE quality into their products than their typical customer expects? Not many. In fact, unfortunately, I’d be willing to bet that most of us could count on one hand the number of products we’ve purchased over the past year that offered quality/durability that was BETTER than we expected. Although this is a sad commentary on the business world we currently live in, it is a pretty accurate reflection of the attitude of most companies these days. Why would today’s automobile manufacturers be any different?
Of course, that being said, I have no proof of the above statements. There do not appear to be any websites out there collecting oil analysis data from GM and Mercedes owners to compare the ACTUAL oil quality to that “measured” by the oil life monitors. I looked. In fact, if you happen to know of one, please let me know – I’d love to see the results. I’m guessing I know what they’d be, but I’m certainly open to the possibility that I’m wrong.
I think the main thing to remember is, nobody yet REALLY knows just how accurate these oil monitoring systems are nor how conservative their oil change interval recommendations are. So, be careful how much trust you put on their oil change interval recommendations.
Syn vs. Petro – Does INITIAL Oil Quality Affect Recommendations
Well, that’s an interesting question. As it turns out, these systems can’t tell whether you’ve got synthetic or petroleum oil in the crankcase, and, this DOES make a difference. In fact, we can see this in the light of a class action lawsuit that was filed against Mercedes Benz a few years back.
Apparently, the MB FSS assumes the use of synthetic oil in the engine. Most Europeans are using synthetic oil by default, since typical oil drain intervals in Europe are MUCH longer than those recommended here in the states (although that gap is closing). In contrast, most North American drivers are still using petroleum oil.
Well, there were no significant warnings given to these MB owners with regard to the FSS units and the use of petroleum vs. synthetic oils. So, many users were utilizing petroleum oils and using the FSS as a guide for when to change their oil. Unfortunately, since the FSS was designed to recommend SYNTHETIC oil drain intervals, severe sludging was occurring in these vehicles. The petroleum oil simply couldn’t hold up for the oil change intervals the FSS was recommending. Bad news for your engine.
In the end, the vehicle owners won their suit and there was a 32 million dollar settlement issued against Mercedes. It is my understanding that MB is now very careful to make it explicitly clear what type oils should be used in order to rely on the results of their FSS monitor.
So, clearly it makes a difference. And, since these systems can’t tell what type of oil you’re using, you’ll need to adjust accordingly. The way I understand it, the GM units assume petroleum oil usage (with the exception of vehicles which specifically require synthetic lubricants – such as the Corvette). So, if you’re using synthetic oil in a GM vehicle that does not specifically require it, the oil life monitor will likely “go off” much sooner than necessary.
I have heard that you can have the dealership adjust these units to account for the fact that you’re using synthetic oil, but, even then, there are significant differences in quality from one synthetic to another, so this may still not be completely accurate. If you’re using a premium synthetic oil which is designed for much longer oil drain intervals (such as AMSOIL’s 25,000 mile oils or Mobil 1 Extended Performance 15,000 mile oils), the unit will very likely “trigger” sooner than necessary. However, at least you’ll know that you have a considerable margin of error due to the enhanced quality that is built into those oils.
Change the oil
You have probably heard this a million times before, but this particular point ears repeating, especially if you live in a climate with harsh winter conditions. Oil designed for cold weather use cannot provide proper lubrication in hot weather because it thins out too much. Replace the oil with the grade recommended for summer use, and don’t forget to replace the filter as well.
If your wallet can stand the extra strain, replace the oil with fully synthetic oil, even if it is not specifically recommended by the manufacturer of your vehicle. Synthetic oil remains stable under a wider range of temperatures than regular mineral oil, with the added bonus that it provides almost twice the lubrication of mineral oil, which is good for any engine, and especially older, high mileage engines.
Replace the engine coolant
You have no doubt heard this a million times before as well, but proper auto maintenance requires that the engine coolant be replaced at least once a year. Apart from lowering the boiling point of water, the correct concentration of anti-freeze also prevents the corrosion of aluminum engine parts and components, which can cause serious issues, including engine failure.
Internal corrosion can open up leak paths through which coolant can be lost either to the outside of the engine, or into cylinders where it interferes with the combustion process. Coolant can also leak into the engine oil, with potentially disastrous results if the problem is not caught and resolved in time.
However, always follow the manufacturer’s recommendations regarding the amount of anti-freeze to add to the cooling system. Too much is as bad as too little; too much anti-freeze actually lowers the boiling point of water, meaning that your engine can overheat even though you have just replaced the coolant.
Check the battery
Hot, humid conditions kill more car batteries than even the coldest winters, so cut down on unexpected auto maintenance and maintenance costs by ensuring that your battery is up to the demands of summer conditions. Even marginally defective batteries can cause all manner of electrical issues, such as sporadic or unexpected trouble with alarm/security/anti-theft systems, low fuel pressure, difficult starting, or even rough idling, and/or rough running- among others.
Have the battery tested at a specialist battery dealer, and check that it can deliver the required cranking amps. Replace the battery if there is even the slightest doubt about its condition.
Remove road salt
If you live in an area where the roads are treated with salt during winter, be sure to have all salt deposits removed from the wheel wells and other places where slush tends to collect. Salt is highly corrosive, and not removing it will definitely cause rust and corrosion to set in. Once corrosion sets in, it may be impossible to stop or remove, so be sure to have all traces of salt removed as soon as the weather improves.
Check tires and tire pressures
Proper auto maintenance includes checking the condition and inflation of all tires, including the spare wheel. Tire pressure is as important as tire tread depth, so as soon as the weather improves, adjust the pressure in the tires to allow for heat expansion. High ambient temperatures and hot road surfaces can cause the air in a tire to expand, which can increase the pressure inside the tire by as much as 15% or more.
Never rely on the tire pressure monitoring system to warn you of under inflated tires. These systems are notoriously inaccurate, and a tire can be under inflated by as much as 25% before an alarm or warning light is triggered. Use a good quality digital tire pressure gauge to check your tire pressures at least once a week to maintain tire pressures at the recommended level.
Check the A/C system
In some climates, proper auto maintenance involves ensuring that the air conditioning system is fully functional, so avoid the rush and have your A/C system checked out before summer really sets in. Listen out for any unusual noises, sounds, or odors coming from the system, and have all faults repaired before a minor issue becomes a huge problem.
The best way to maintain an air conditioning system is to use it- even in the depths of winter. This not only keeps all the moving parts in the compressor lubricated, but it also largely prevents micro organisms from establishing colonies in the system’s ducting. So if you have not used the A/C system during the past winter and it now gives of an odor that smells like something had died in it, you have an unwelcome growth of bacteria, mold, and/or fungi in the system.
Remove the colony (and its odor) by spraying an approved disinfectant into the system, or have it done, because if you don’t, the smell could get so bad that it might become impossible to remove it from the car. Worse though, not treating this problem could cause serious respiratory problems in children, elderly persons, and/or persons with compromised immune systems.
When it comes to changing the oil in one’s car, the first thing needed is to consult the owner’s manual to find the type of filter and how many quarts of oil are needed. Other items are a good drain pan, and funnel. These can be purchased at the auto parts store. It’s a good idea to have a basic set of tools. An extra tool that makes oil changes easier, in my opinion, is an oil filter wrench (specialty tool). I use a socket and ratchet set when I change oil. I’ve also known people who would use an adjustable wrench. I don’t consider this a good idea because you can slip off of the drain plug and damage the flats.
At the auto parts store, you can look up the type of filter required for your car. I would recommend buying the oil in a five quart container so you can pour your used oil into it after the new oil is poured into your car’s engine.
Once you’ve got your supplies and tools, it’s time to get under the car. You might not fit and you’ll have to jack the car up. One other good investment would be ramps. I always save a big piece of cardboard to lay on when I’m under a car. I have a creeper too, but it sets to high for some cars I’ve worked on. Start your car and let the engine idle for about 5 minutes. That way the oil is warm and will drain much easier.
Crawl under your car and make sure the drain plug, you’ll be removing, is on the engine pan. Some new cars have a transmission drain plug. Have your tools with you when you get under the car, and select the proper socket to use. It may be metric or standard. Make sure to have your drain pan close by when you remove the plug. When the oil from the plug hole is down to a few drips, re-install the plug. Locate the engine oil filter. If you’re not sure what it looks like, take the new one out of the box. Some filters are easy to get to, to change, others are not. Use an oil filter wrench, if you have one, and turn the filter counter-clockwise to remove it. Make sure the drain pan is under the filter, if possible, to catch the oil spilling out. Next wipe some oil on the seal of the oil filter and install it, turning it clockwise until it’s tight, then turn it 3/4 of a turn more, this insures it won’t leak.
Petroleum oil begins to break-down almost immediately. A high quality synthetic, on the other hand, can last for many thousands of miles without any significant reduction in performance or protection characteristics. Synthetics designed from the right combination of basestocks and additives can last indefinitely with the right filtration system.
As alluded to above, the first major difference between petroleum and synthetic oil is heat tolerance. Flash point is a technical specification referenced by most oil manufacturers which is an indicator of heat tolerance.
The lower the flash point of an oil the greater tendency for that oil to suffer vaporization loss at high temperatures and to burn off on hot cylinder walls and pistons. This leads to oil thickening and deposit build-up on critical engine components.
So, the higher the flash point the better. 400 degrees F, in my opinion, is the absolute MINIMUM to prevent possible high consumption and oil thickening due to burn-off. Higher would definitely be better.
Today’s engines are expected to put out more power from a smaller size and with less oil than engines of the past. Therefore, the engines run much hotter than they used to. That puts an increased burden on the oil. Synthetics are up to the task. Petroleum oils are better than they used to be, but can still be a little overmatched. Nevertheless, even though synthetics are MUCH less prone to burn-off than are petroleum oils, there can still be a small amount of burn-off during extremely high temperature operation.
Since some motor oil “burn off” will occur whether using synthetic or petroleum oil, it becomes important to discuss the manner in which petroleum and synthetic oils burn off. Because it is a refined product and the refining process can only do so much, petroleum oil molecules are of varying sizes (the very smallest and largest of which are removed during the refining process – what is left is a smaller range of molecular sizes, but there is still significant variance in molecular size from one to another). Hence, as a petroleum oil heats up, the smaller molecules begin to burn off faster and easier than the larger molecules.
Moreover, some of those smaller molecules are actually contaminants that were left behind from the refining process. You see, when crude oil comes out of the ground it is a conglomerate of many different molecule types, a large portion of which are not useful for lubrication purposes at all. The refining process is designed to remove as much of those contaminant molecules as possible, but only so much can be done without raising the cost considerably.
As all of these smaller molecules burn, deposits and sludge are left behind to coat the inside of your engine which, obviously, reduces the efficiency of your engine and can also lead to greater heat build-up in your engine. Anytime heat increases beyond what is normal for an engine, longevity will suffer.
== Need A Heating Blanket for Your Engine?
Obviously, that would be silly, but, in some respects this is exactly what petroleum oils create inside your engine. You see, the larger molecules within your oil do not flow nearly as easily as the smaller molecules do (consider the difference in “pourability” of a heavy weight oil vs a light weight oil). Because of this, the larger molecules tend to be pushed to the “outside” of the oil stream, collecting at the surface of your engine components while the smaller molecules flow down the center of the oil stream between the larger molecules.
Thus, the larger molecules tend to “blanket” the components of your engine, trapping the heat there as opposed to pulling the heat away into the oil stream. Of course, this only exacerbates the heat problem as friction builds-up. As smaller molecules within the oil burn off, the larger, heavier petroleum oil molecules are all that is left to protect the engine. This makes the “heating blanket” effect even worse.
In contrast, synthetic oils, because they are not refined or purified from crude oil, but rather are designed within a lab for lubrication purposes, are comprised of molecules of uniform size and shape. Only the molecules that are useful to the purposes of lubrication and cooling are present within the oil, and only the molecule size that is desired for the particular viscosity being manufactured.
Therefore, even if a synthetic oil does burn a little, the remaining oil has the same chemical characteristics that it had before the burn off. There are no smaller molecules to burn-off and no heavier molecules to leave behind. No oil thickening. No “heating blanket” effect.
Moreover, synthetics contain few, if any, contaminants as compared with petroleum oils since they are not a refined product. As a result, if oil burn-off does occur, there are few, if any, contaminants left behind to leave sludge and deposits on engine surfaces. Obviously, this leads to a cleaner burning, more fuel efficient engine.
In addition, because the molecule sizes are so uniform in a synthetic oil and there is no “heating blanket” effect, synthetics do a much better job of “cooling” engine components during operation. A cooler running engine means longer engine life. AND, oil temps will often be 10 to 30 degrees cooler than with petroleum oils because the heat dissipates so much better with a synthetic. Cooler running oil means longer oil life and better protection.
Choosing the most suitable motor oil for your car is the aspect that should not be disregarded. This is because not all the oil types fit one and the same vehicle and some of them may even affect the way the auto will function. There are a few important questions you need to answer before shopping for the best engine oil brand. These questions concern the type of the vehicle you own, its age, manufacturer’s guidelines and the weather conditions that prevail in your location.
To start with, it is essential to recollect the type of engine oil you have been using before. If you have never inquired about this issue or if this is the first time you have to change the motor oil, then it makes sense to find out what engine oil you used before. Having found that out, analyze how exactly your car functioned when you used the oil. If everything was all right and you didn’t have to fix the engine problems, then you don’t have to look for another motor oil.
The next point that is worth consideration is checking the type of oil recommended by the manufacturer. This is especially true if you own a new vehicle, which comes with the warranty. In this case, changing the oil is not allowed. Otherwise, the manufacturer may not repair the car for free in case of necessity.
If your car is not new, this means that its engine may be worn. As a result, the parts of the engine may become smaller, forming space between them. To fill this space, you will need think oil, so find out more about heavy single-weight oil brands that will fit your car most of all.
Finally, it makes sense to take into account the weather conditions that prevail in your location. Thus, if you live in the mountainous area, where the temperature changes are extreme, then it is better to purchase multi-weight types of oil, which are allowed to be used under any temperature regimes. Pay attention to the “W” index, which reflects the way the oil “behaves” in hot and cold weather. The higher this index is, the worse the oil works in autumn and in winter, when it is too cold outside. Keep that in mind.
Different motor oil types are manufactured for various purposes. To select the one that meets your requirements and needs, you have to understand the essence of such notions as the viscosity ratings, classification codes and oil additives. Let us have a closer look at each notion.
Each type of oil has specific viscosity rating that shows how the oil flows in the engine. With regard to this aspect, customers choose between two popular types of oil – single- and multi-viscosity oils. The prevailing amount of vehicles run on the second type of oil, because it can be used under any temperature conditions. Actually, the higher the viscosity index is, the thicker the oil proves to be and the worse flow capability it has. As a rule, the first number in the combination signifies the way the oil flows during the autumn-winter season, while the second number shows the way it flows under the hot temperatures in spring and summer. If you don’t know the most suitable viscosity index for your automobile, consult the manufacturer or the manual that comes with the vehicle.
Speaking about the oil additives, they are required to ensure the best engine performance. They contribute to the way the engine is cooled and cleaned by the oil. In high quality engines, the cost of the oil additives constitutes over 25% of the overall cost of the oil.
All types of motor oil have unique classification codes that reveal the levels of engine protection and economy of the fuel they ensure. The popular oil classification codes include: the API starburst label, the API donut label for diesel motor oil and the API donut label for gasoline motor oil. You should select the one, which fits your vehicle.