Another coolant question - it's that time of year again

[donbryce]

I hesitated to post this, but decided that the issue deserves another visit. My 85 380SE is soon to be put into winter storage, so I have coolant on my mind. My concern is mainly with corrosion and freeze prevention, but I realize others living in more hospitable climes might pay more attention to the lower boiling temps afforded by a proper water/coolant mix.
I did the search, and have concluded that: (1) all the 'enlightened' on this board, or 98% anyway, recommend MB coolant over the 'green' stuff, (2) Valvoline Zerex G-05 is as good as MB's coolant, and (3) whatever it is, MB/Zerex/green, it's a good idea to flush and change it every 2 years or so (not the 98% agreement here though).
OK, so here's what I don't understand. What makes an older Mercedes engine so special that the green stuff isn't good for it?
It seems to me that there are lots of engines out there that are mostly cast iron with some aluminum parts like the rad and water pump in which the green stuff works just fine. Providing the recommended flushing and change is done, it strikes me as silly to be running around looking for MB or Zerex coolant when a good quality regular coolant should work just as well.
Is it just for newer engines with aluminum heads or whatever that his applies to, or is there some objective basis for this anti-green mania?

[Duke2.6]

"Green stuff" is loaded with salts that precipitate out and clog up radiators and heater cores. OEs have moved completely away from it, and as a result, most manufacturers are phasing it out. All OEMs now use either a hybrid type that has mostly organic inhibitors with a small dose or silicates, or pure organic inhibitor packages that have no inorganics.

The industry consensus appears to be that hybrids should be used to replace cars that originally had green antifreeze.

Duke

[donbryce]

I thought that all this 'organic' content stuff was to promote environmental friendliness. Now I'm really confused. I'm not a chemist, so how do I select a coolant that doesn't have these 'salts' in it? Surely MB and Zerex aren't the only 2 out there that meet this criteria? BTW, I can't find Zerex G-05 here, and the nearest MB dealer is 2 hours away. I'd just like to hear from someone who can endorse a competitor, and why his product is superior to the 'green stuff'.

[mpolli]

I have a couple more questions and hopefully Duke can answer them all!!

1) Is there any relationship between these "organic" components and the "non-toxic" types advertised (Sierra for example)? I am guessing that even the MB or G-05 is still toxic. True? What makes the Sierra non-toxic?

2) Many shops now "recycle" or "rejuvinate" coolant. How do they do this considering the variety of coolants that they are draining out of cars. What do they end up with?

Thanks,

Mike

[tangofox007]

Where can Xerex G-05 generally be found?

[Duke2.6]

The inorganic/organic/hybrid corrosion inhibitor packages have nothing to do with environmental friendliness. They are different corrosion inhibitor strategies. Sierra is propylene glycol based. Propylene glycol is still toxic, but you or your dog would have to drink more to get sick or kill yourself. Sierra brand advertising is just hype. You are not "helping the environment" by using it, and you may well be damaging your cooling system. I have no idea what corrosion inhibitor technology is present in Sierra brand, and I would never consider using it.

I don't know DC's position, but GM specifically recommends AGAINST the use of propylene glycol antifreezes because propylene glycol has different thermal capacity than ethylene glycol. Most OEs design their cooling systems to operate best both in terms of heat transfer and corrosion protection with a 50/50 mix of commercial antifreeze and water.

If you do your own coolant changes you should check with your local authorities as to how you should dispose of old antifreeze. In my city it is okay for homeowners (but NOT commercial shops) to dump old antifreeze down sanitary drains (like the toilet) because we are connected to a state-of-the-art sewage treatment plant that breaks down the glycol and removes any heavy metal ions like lead. You should NEVER dump antifreeze down storm drains, septic tank systems, or in the woods.

I am not aware of any OE who approves recycled antifreeze, and most specifically recommend against it. Think about this. Do you trust some local shop to use a machine to "purify" and then add a proper concentration of the OE's recommended corrosion inhibitors over the ability of a major chemical company to produce a consistent quality product that is properly formulated to what the label says it is? I would never personally use "recycled antifreeze" and would never recommend it to others.

Most of the local auto parts chain stores in my area now carry Zerex G-05. If you can't find it go to the Valvoline web site and see if they have a list of retailers. Im not personally aware of any other brand product except G-05 (and MB brand) that meets the DC spec.

Duke

[mpolli]

Is the G-05 the same color as the MB coolant?

Mike

[Duke2.6]

Sort of a pale yellow - close, but not necessarily an exact match.

Duke

[roy wood]

local NAPA is now carrying G-05 for about $7 a gallon; also at Auto Zone (more like $10/gal).

[Hatterasguy]

I still don't understand why people want the G-5 stuff when the oe stuff is $9 a gallon.

[Duke2.6]

G-05 is the same formulation as MB brand, is approved by DC, is more readily available through parts stores, and is cheaper than at the dealer.

Duke

[tangofox007]

In my area (GA) the OE antifreeze is $12 at the dealer. Xerex G-05 is $9.49 at Pep Boys. Autozone says that they have discontinued the Xerex brand and are replacing it with the Peak brand.

[DaveL]

Propyline Glycol is approved as a food additive, so I don't think I would consider it "toxic".

However, once exposed to the radiator and engine, all coolants pick up various metal deposits and other nasty stuff that makes them unfit for human or animal consumption.

Used propylene glycol antifreeze is considered toxic, but you can drink it when fresh (and you do it you consume "artificial" milkshakes like McDonald's, etc... Prop glycol is used as a thickening agent...)

-David

[teky]

ohh yuk big macs just took a dive

[JulesJNM]

I bought a '92 190E 2.3 last March and I noticed that the coolant color in the reservoir is somewhat whitish very light brown in color. Is this a normal color. Thank you for all the information on Xerex G-05 which I will use to change the coolant on my '92 190E.