However, Orange, Red, Yellow and the others may indicate a lack of phosphate corrosion inhibitors, but just to be sure, read the label.

When I bought my Mercedes and the local dealer's shop tech told me right off the bat that I had the "wrong color" antifreeze in my car's cooling system, my immediate reaction was that he was just some dude trying to sell me Mercedes antifreeze. In retrospect, I see my reaction to that comment was a result of my own ignorance, speculation, and skepticism.

After becoming a member here at MercedesShop, I read several threads about antifreeze that got me to thinking about my own experiences with cooling systems in commercial vehicles, and the problems I have seen that were caused by multiple metallic engine components causing electrolysis, and the cavitation and erosion of engine blocks caused by improper anti-corrosion agents being used in the wrong concentrations, as well as all of the cases of early cooling system failure from using the wrong specialized corrosion additives (SCA) in those engines. It also started me thinking about my experience with marine applications where zinc is used as a sacrificial anode to prevent erosion of outboard drives and other components on boats.

So I started doing some research, and the more research I did, the more I learned about anti-corrosion additives, antifreeze, cooling systems, and how these all can relate to premature engine cooling system failures. I also learned about the companies who make these antifreeze products for our vehicles, and what the differences are in how their products are manufactured, and why. As I learned something new, I posted it here as unbiased information with links supplied so that anyone could see where I got my information from, and what exactly was being stated by the source.

One thing I found out was that the formulation for "Mercedes-Benz Antifreeze Anticorrosion Agent" was arrived at due to the fact that the mineral content, or "hardness" of the water, in Europe is greater than other parts of the world, and the use of a phosphate-based anticorrosion agent in antifreeze (like Prestone has) causes those minerals to "drop out" of solution, form "clumps" and attach to the interior surfaces of the engine cooling system until they build up sufficiently to become structurally unstable, break loose, and then accumulate in restricted cooling system passageways, causing inefficient cooling, eventually resulting in "hot spots" in the engine, and in some cases, blocked coolant passageways. The other effect this process has is to cause the coolant to act as an abrasive "cocktail", causing both electrolysis and erosion that results in premature failure of cooling system components like radiators, heater cores, and water pumps. In fact, it also has a tendency to eat straight through engine blocks via the cylinder wall cooling jackets. This has been a major problem in the commercial vehicle industry, and has also affected Mercedes-Benz motorcars to a great extent.

Primarily, this "Mercedes Antifreeze Anticorrosion Agent" formulation was developed as a result of three basic factors. One, all engines need to be cooled properly and water does the best job of doing that, but it also freezes, boils, and is itself corrosive. And when you add straight ethylene glycol, which is also highly corrosive, that makes it even more destructive; and that is why antifreeze/coolant requires a corrosion inhibitor. Two, the engines in Mercedes' and their cooling systems are primarily aluminum, with some copper, iron, and brass, which together add special problems with corrosion and electrolysis. So finally, the primary cooling agent itself needs to be water with an antifreeze agent added to reduce boilover and freezing that now necessitates the inclusion of additives to add lubrication, and to prevent electrolysis, corrosion and erosion of these various metallic cooling system components while not adversely reacting to the variations in mineral content in the water itself.

So when Mercedes tells you in your owner's manual that "Your vehicle contains a number of aluminium parts. The use of aluminium components in motor vehicle engines necessitates that anticorrosion/antifreeze/coolant used in such engines be specifically formulated to protect the aluminium parts. (Failure to use such anticorrosion/antifreeze/coolant may result in significantly shortened service life." they know what they're talking about, because they did the research after having the problems present themselves, and they had to come up with real answers for those problems.

When they add "While there may be a number of anticorrosion antifreeze/coolants available which will provide the requisite protection, all such products have not been tested for Mercedes-Benz vehicles. The following product, however, is recommended for use in your car: Mercedes-Benz Anticorrosion/Antifreeze Agent.", they are not saying that Prestone is ok, nor are they saying that Prestone didn't pay them to test Prestone antifreeze. They are stating it in that manner as a matter of legalities. First, Mercedes cannot by law specify that you must use their products in your car; and second, if they claimed that anyone else's product(s) weren't safe or acceptable, they would be setting their company up for lawsuits from every antifreeze manufacturer that didn't make product for them. Besides, there are federal laws about restriction of trade, etc. Every document ever written in the history of man is open to interpretation, but I believe that the intrepretation of this section of the Mercedes owner's manual in this instance is seriously biased, and even if I did agree with Wm. Lewallen on the selection of antifreeze, I could not in good faith agree with the basis for this particular thread.

I honestly admire and respect both Larry Bible and Wm. Lewallen for their expertise and years of experience with Mercedes-Benz vehicles. I have no reason to doubt either one of them when they claim that the use of green colored antifreeze with a phosphate based corrosion inhibitor, regardless of brand name, has worked well for them. But I would suggest that anyone who believes that their experiences are the norm with regard to Mercedes cooling system maintenance and failures do their own research on this subject, and come to their own conclusions for maintenance of their own cars, based on where they live, and whether or not they choose to use demineralized water or plain tap water mixed with whatever antifreeze in their Mercedes cooling system.

Actually, I doubt if most people have even taken the time read half of the material available on this subject in the archives on this site, or to click on the links provided. Anyone with a logical mind, and better than a "5th grade" education who follows those links, reads the information, makes the same phone calls to the companies, and asks similar questions based upon pure common sense should arrive at the same conclusion I have. I've got to say that what I resent most is snide comments from other members bent on disproving something that they haven't done any independent research on. It shows no respect for the effort some of us have put into trying to find objective answers to this issue.

Finally, at the risk of repeating myself once too often, EVERY manufacturer of antifreeze in this country has now developed a formulation of an ethylene glycol base antifreeze with an organic acid corrosion inhibitor trying to imitate Glysantin. You can call it "extended life" antifreeze if you like, but every company makes at least one, even Prestone. And they make it because it's better for vehicle cooling systems like those in commercial vehicles and automobiles that are now being made the way cars have been made in Europe for some time, like Mercedes-Benzes. BASF was the pioneer of this corrosion inhibitor technology with the Glysantin formulation, and all their competitors are just playing "catch-up". Time will tell, but when I state that phosphate-based corrosion inhibitor antifreezes are on the way out, I have good reason to do so, because phosphate is just as outdated as the nitrates, amides, and all of the other corrosion inhibitors that used to be part of automotive antifreeze and aren't anymore.

I firmly believe that there is no better antifreeze anticorrosion agent made today than what is sold by Mercedes Benz, and I say that after having done a great deal of research on the subject. So go buy whatever's on sale to save a few pennies, or whatever antifreeze you want to put in your car, but please don't ever imply that I am recommending the factory product because I'm some idiot who doesn't know any better, or that I'm a person with more money than good sense. There's an old expression "don't judge a man until you have walked a mile in his mocassins". Put on some mocassins, and let's take a walk, shall we?

[Edited by longston on 06-08-2001 at 11:57 PM]

__________________

Scott Longston
Northern California Wine Country...
"Turbos whistle, grapes wine..."