| Recently, we have seen the introduction of oil | | | | synthetic oil in the engine. Most Europeans are using |
| monitoring systems in some vehicles, most notably in | | | | synthetic oil by default, since typical oil drain intervals |
| General Motors and Mercedes vehicles (although I | | | | in Europe are MUCH longer than those recommended |
| believe BMW may have a similar system as well). The | | | | here in the states (although that gap is closing). In |
| systems do not all work the same. Mercedes actually | | | | contrast, most North American drivers are still using |
| has two slightly different systems while the General | | | | petroleum oil. |
| Motors system is the same for all vehicles (at least | | | | Well, there were no significant warnings given to |
| those that have it installed). | | | | these MB owners with regard to the FSS units and |
| Mercedes calls their unit a "Flexible Service System". | | | | the use of petroleum vs. synthetic oils. So, many |
| The FSS on some Mercedes vehicles monitors actual | | | | users were utilizing petroleum oils and using the FSS |
| oil quality as well as operating conditions (such as the | | | | as a guide for when to change their oil. Unfortunately, |
| number of cold starts, average engine temp, mileage | | | | since the FSS was designed to recommend |
| driven, oil sump level, rpms, etc.). To measure oil | | | | SYNTHETIC oil drain intervals, severe sludging was |
| quality, there is actually a sensor that measures the | | | | occurring in these vehicles. The petroleum oil simply |
| electrical conductivity of the oil. The higher the | | | | couldn't hold up for the oil change intervals the FSS |
| conductivity of the oil, the greater the need for an oil | | | | was recommending. Bad news for your engine. |
| change, according to Mercedes. Of course, this isn't | | | | In the end, the vehicle owners won their suit and |
| likely a perfect model, and will not be nearly as | | | | there was a 32 million dollar settlement issued against |
| accurate as an actual oil analysis in determining true oil | | | | Mercedes. It is my understanding that MB is now |
| quality, but it is better than no measurement at all. | | | | very careful to make it explicitly clear what type oils |
| At any rate, as electrical conductivity increases, this | | | | should be used in order to rely on the results of their |
| value is combined with all of the operating condition | | | | FSS monitor. |
| data and run through a special algorithm to determine | | | | So, clearly it makes a difference. And, since these |
| if the oil is ready for a change. When a change is | | | | systems can't tell what type of oil you're using, you'll |
| necessary, a light will flash on the instrument panel | | | | need to adjust accordingly. The way I understand it, |
| indicating such. | | | | the GM units assume petroleum oil usage (with the |
| The other Mercedes FSS unit, which will be | | | | exception of vehicles which specifically require |
| somewhat less accurate, does not actually measure | | | | synthetic lubricants - such as the Corvette). So, if |
| the electrical conductivity of the oil, so it is not | | | | you're using synthetic oil in a GM vehicle that does |
| testing the quality of the oil in any way. It does, | | | | not specifically require it, the oil life monitor will likely |
| however, measure all of the operating conditions and | | | | "go off" much sooner than necessary. |
| uses the algorithm to predict when an oil change will | | | | I have heard that you can have the dealership adjust |
| be necessary. | | | | these units to account for the fact that you're using |
| This is actually how the GM oil monitoring system | | | | synthetic oil, but, even then, there are significant |
| works. It does not measure oil quality via electrical | | | | differences in quality from one synthetic to another, |
| conductivity or via any other means. It simply | | | | so this may still not be completely accurate. If you're |
| measures operating conditions and "calculates" when | | | | using a premium synthetic oil which is designed for |
| an oil change should be necessary based upon those | | | | much longer oil drain intervals (such as AMSOIL's |
| conditions. | | | | 25,000 mile oils or Mobil 1 Extended Performance |
| So, How Accurate Are These Units? Can They Be | | | | 15,000 mile oils), the unit will very likely "trigger" |
| Trusted? | | | | sooner than necessary. However, at least you'll know |
| That's a tough question to answer at this point. First | | | | that you have a considerable margin of error due to |
| off, these systems haven't been in use long enough | | | | the enhanced quality that is built into those oils. |
| to really have much in the way of hard statistics | | | | Conclusions on Oil Monitoring Systems and Drain |
| comparing vehicle/engine life with or without these | | | | Intervals |
| systems in place. Second, many drivers do not trust | | | | It's difficult to say with certainty whether these oil |
| the longer drain intervals recommended by these | | | | monitoring systems are accurate or conservative |
| units and change the oil sooner anyway, offering, | | | | enough to completely trust their recommended oil |
| again, little data to show whether the drain intervals | | | | change intervals. It seems that the best advice we |
| recommended by these systems are conservative | | | | can give is, if you intend on driving your vehicle as |
| enough to maintain engine protection equal to that | | | | long as possible and are looking for the best |
| attained with shorter change intervals. | | | | protection possible, you'll likely want to be more |
| Since these units do not FULLY measure oil quality, in | | | | conservative than your oil monitoring system will be. |
| the same way that an actual oil analysis would, it is | | | | You may want to wait for the monitoring system to |
| unlikely that they are completely accurate, but there | | | | "flag" the oil as ready for a change once or twice to |
| is good reason to believe that they are fairly | | | | get a better gauge for your change interval decisions. |
| accurate. | | | | If you're driving a Mercedes or a GM vehicle that |
| The problem, from my perspective is, how were the | | | | requires the use of synthetic, make sure you ARE |
| limits set? Quite frankly, it's in the best interests of | | | | running a full synthetic oil (not just a blend - it's not |
| vehicle manufacturers to have their engines begin to | | | | the same), if you're going to do this. |
| decline in performance somewhere shortly after the | | | | If the manufacturer requires/recommends synthetics |
| 100,000 mile marker. Many people these days don't | | | | and you ARE using an "off the shelf" synthetic oil, it |
| expect a vehicle to perform well much beyond 100K, | | | | would be a good idea to use the oil monitoring |
| so building a vehicle and recommending maintenance | | | | system's change interval recommendation as a base |
| practices that will help the vehicle perform longer | | | | (assuming your driving habits remain pretty constant) |
| than that is not in the best interest of the OEMs. | | | | and then cut that back by at least 25% for |
| So, I would be willing to bet that, if you are an | | | | subsequent changes for the best protection. In other |
| individual that likes to keep your vehicle as long as | | | | words, if you let the monitoring system go till it says |
| possible, oil quality limits have been set to a lower | | | | "change the oil", and it flags at 10,000 miles, then you |
| standard than would be appropriate to getting the | | | | should consider doing intervals of about 7500 miles to |
| absolute most mileage from your vehicle. It really only | | | | stay conservative. |
| stands to reason. | | | | If the vehicle manufacturer requires/recommends |
| How many companies do you know of these days | | | | synthetic oils and you are NOT doing so, I |
| that build MORE quality into their products than their | | | | recommend that you rethink your position. First, if |
| typical customer expects? Not many. In fact, | | | | the manufacturer "requires" the use of synthetic, |
| unfortunately, I'd be willing to bet that most of us | | | | you're putting your engine in jeopardy. OEMs do not |
| could count on one hand the number of products | | | | REQUIRE synthetic unless they've had problems with |
| we've purchased over the past year that offered | | | | petroleum oils previously. If you choose to go that |
| quality/durability that was BETTER than we | | | | route, understand you are definitely putting your |
| expected. Although this is a sad commentary on the | | | | engine at risk. |
| business world we currently live in, it is a pretty | | | | If synthetic is simply "recommended", then you may |
| accurate reflection of the attitude of most | | | | be ok to use petroleum oil, if that's your decision, but |
| companies these days. Why would today's | | | | it would be a good idea to have the dealership adjust |
| automobile manufacturers be any different? | | | | your oil monitoring system to account for your use |
| Of course, that being said, I have no proof of the | | | | of petroleum oil. If they can't or won't do so, either |
| above statements. There do not appear to be any | | | | considering going to synthetic or don't use the oil |
| websites out there collecting oil analysis data from | | | | monitoring system as a judge for when you should |
| GM and Mercedes owners to compare the ACTUAL | | | | change your oil. |
| oil quality to that "measured" by the oil life monitors. I | | | | If there is no specific recommendation or |
| looked. In fact, if you happen to know of one, please | | | | requirement to use synthetic, then the oil change |
| let me know - I'd love to see the results. I'm | | | | interval specified by your oil monitoring system will be |
| guessing I know what they'd be, but I'm certainly | | | | based upon the assumption that petroleum oils are |
| open to the possibility that I'm wrong. | | | | being used. If you ARE using petroleum oil, then do |
| I think the main thing to remember is, nobody yet | | | | as suggested above. Get a baseline and then cut |
| REALLY knows just how accurate these oil | | | | back by at least 25% for best protection. If you're |
| monitoring systems are nor how conservative their oil | | | | using a synthetic, ask the dealership to adjust the |
| change interval recommendations are. So, be careful | | | | unit to account for this. Then, whatever interval the |
| how much trust you put on their oil change interval | | | | unit suggests, again, cut it by about 25% or more for |
| recommendations. | | | | best protection. |
| Syn vs. Petro - Does INITIAL Oil Quality Affect | | | | And, if you are using one of the 25,000 mile AMSOIL |
| Recommendations | | | | products, which are recommended/guaranteed for |
| Well, that's an interesting question. As it turns out, | | | | that interval, then you can either choose to use that |
| these systems can't tell whether you've got | | | | recommendation OR that of the oil change monitor. |
| synthetic or petroleum oil in the crankcase, and, this | | | | Most frequently, in this case, the oil monitor |
| DOES make a difference. In fact, we can see this in | | | | recommendation will be a SHORTER drain interval |
| the light of a class action lawsuit that was filed | | | | than that recommended by AMSOIL, so if you go |
| against Mercedes Benz a few years back. | | | | that route, you'll simply be erring on the conservative |
| Apparently, the MB FSS assumes the use of | | | | side. |