I'm not sure if there are no other coolants on the approved list because Mercedes wants to push their own product or if it's because the coolant manufacturers don't want to pony up the cash to Mercedes to have them test their products. There is a whole lot more motor oil used than coolant, so why doesn't Mercedes sell and recommend their own label oil? There are many approved oils, more for the European market than in the US, but still plenty to choose from.

I'll be interested to hear what the latest word from Zerex is.

Len

Coolant order to use in your MB:
1) G-05 or MBZ coolant
2) Prestone Yellow
...
9) Green crap
10) Straight water
...
998) dog urine
999) Dexcool

Note: I forgot to clarify something in my first post. The Texaco antifreeze I speak of is NOT the Texaco Extended Life (Dex-Cool) that it is assumed to be. It is regular, old fashioned, Ethylene Glycol Based, Green, Texaco antifreeze. I would NEVER put Dex-Cool in anything that wasn't cursed with it from the factory;) .
Thanks, and God Bless,
Dave.

This table of coolants may help people understand the different coolants out there. For starters, one cannot go by color alone.

http://www.eetcorp.com/antifreeze/Coolants_matrix.pdf

personally, I'd like to keep my Mercedes original using the oe coolant. Whenever someone brings in a pre purchase inspection, I check the coolant type. 10 out of 10 times, if it has the oe coolant, that usually means it is dealer serviced or done by an indy shop that knows MB's. Which in turn, is usually a better maintained car. If it comes in with dexcool, I can usually expect coat hangers in place of exhaust doughnuts, black tape over the check engine light, non-metric hose clamps, and a bubba's quick lube oil sticker running non synthetic oil in a 2000 MB.
Dave

Excellent points Dave. That would be me too if looking to buy a used Mercedes. Green coolant might not be a dealer stopper, but it would sure get me thinking and looking harder.

Len

dont forget to use distilled h2o when mixing folks!

Agreed. Getting a DB (or DC now) seal of approval just means that they found the time to test it. But, the absolute minimum standard you need is to find coolant approved for aluminum parts. Whether it's as good as the MB fluid will require a long-term test, and I don't want to volunteer my engine/water pump/radiator as a guinea pig.
I can say that I trashed the water pump seal in my 2.3L from the '85 190E when I assumed "all coolants are the same" and used green crap in it. It began leaking within a few thousand miles, presumably because of the accelerated corrosion on aluminum parts. Let me quoth the Raven: "Nevermore!"

A new radiator began leaking within a few thousand miles? If it wasn't a new radiator such a presumption would seem to be flawed.

I think that if we are looking for very precise, data driven explanations as to why one thing is better than another, this is probably the wrong venue to do so. (It is, after all, the internet...) While there are some highly experienced technicians on the board, and a few more who bring their professional experience into the mix, most of us are shadetree mechanics who do this in our spare time.

In other words, you're probably not going to find highly technical, data-driven research as to why the chemical compound in OEM coolant is better than normal ethylene glycol.

The best most of us can expect from any of these questions is that the general consensus will reflect the experience of those of us who have been working with these cars, and then it's up to each individual owner to decide if that particular recommendation is worth the marginal cost over the least expensive option.

For what it's worth, I think of MB coolant like I think of synthetic oil. It's probably not 5x better, but it's still better than the regular stuff, and so I use it. Considering that it's gotten me to 285,xxx miles, that can't be all that bad.

Anthony

Your assignment for tonight, Deanyel: reread the post. Water pump seal does not = radiator.

Also, try a link from more recognized expert:
http://www.asashop.org/autoinc/june97/cooling.htm

IMO, if you're changing coolant every 3 years, so what if it's $30 a gallon? If you use an equation of how much your time is worth based on your profession, how much money have you cost yourself researching the info? Probably at least a few gallons of MB coolant - lol..

I'm no moneybags, but my peace of mind is worth it considering I have to pony up the extra dough only once every 3 years, and I plan to keep the car permanently. It isn't like paying $15 a quart for some MB synthetic oil every 5k.

For that matter, I've gotten 80k out of my front OEM MB brake pads and 140k on the original front rotors. I could buy the discount pads and rotors and save maybe $80 total, but why? The OEMs have proven themselves. I know they perform, so I will buy them again

The difference on the brake pads and rotors, though, is that they usually are the same as the OEM components. Textar, Pagid, Brembo, Zimmermann, ATE etc. all supply MB as OEM's.
The coolants and newer ATF's (722.6 and later) are not easily available outside of MB.

er, right, but the question is the same - it was new and it failed within a few thousand miles? The expert article seems rather neutral on the question.

The part wasn't new
 

but it failed shortly after switching to the cheap green stuff.
The point is that different materials require different chemistries, otherwise you get increased corrosion and failure.