Type of antifreeze
 

I have a 1998 C-280 with 20k miles. Never changed antifreeze. Want to make sure I use the proper antifreeze. Can someone please recommend. The color of the antifreeze in the radiater now is sort of yellowish.

do a search on this site, and you'll probably concur that Mercedes brand anti-freeze is the one to go with

btw why so few miles on such a nice car?

you can also use Zerex G05- it's the same stuff and more easily available.

Go to the dealer or Fastlane and get the MB stuff.

Your radiator fluid is required to be changed every 3 years. You missed the first change interval. I'd call this neglect.

Remember that when radiator fluid gets old, it becomes corrosive.

The only other time interval maintenance item is brake fluid. Mercedes requires brake fluid to be changed every 2 years.

Don't pay attention to the maintenace guide and use the 5 year AF that is orange. I've used it with good results for many more than 5 years. If you buy MB AF you will get "hosed" via price as thay simply buy it from one of the many AF [Dupont etc .] companies and double the price. MB's are regular cars that used to have a reputation as "high" quality cars. They bought Chysler and are now working to design a lower quality car as their stock price reflects to down grading of the marquie.

Peter, I have to disagree with advising anyone else not to follow the maintenance guidlines from the manufacturer. Considering that the cost of doing the two year change of coolant is not going to break the bank, it's penny wise, pound foolish to go 5 years on any fluid.

After 5 years the coolent will cause corrosion, and could start to clog the radiator. MB specs better maintaince standards because they don't want their cars to wear out, they are supposed to last 20+ years. Thats the reason the spec out brake fluid changes every 2 years. MB coolent is $9 a gallon threw Fastlane and is chemicaly different then other coolents. Will you car blow up if you use the green stuff? No but your radiator will go south faster, plus your head gasket won't like it. Thats $500 in parts on my car. Not to mention resale, If I see green coolent in a MB I look at I want to knock the price down.

MTI: It's hard to believe that any or all anti-freeze makers would make their product so that after a certain period of time it would turn into, lets say, ACID or some other dangerous stuff. The EPA says not to discard AF into the ground as it will surely last a long time. I think the idea of changing this coolant every 2 years is just a way to get your car into the dealers service department where they will naturally find need for more work and of course more revenue. I have a 26 year old Chevy. that I rountinly change the AF every 5 to 7 years and have never had a "clogged" radiator. Of course everyone knows a Chevy is a much better auto than a MB, or am I from another planet? What say you folks who have all these terrible problems with their MB cars?

Actually over time it brakes down and becomes acidic, It also starts corrosion. But $9 every two years is cheap, the radiator for your Chevy is probably $100. I just paid $395 for a new one and I plan on making it last as long as possible.

Just my 2 cents.

I guess the only analogy I can lend to this is what my optometrist told me about my 30 day disposable contacts from Ciba. Although they're supposed to gas permeable to the extent that they can be worn non-stop for 30 days, including sleeping, he suggested that I take them out one day out of seven with the admoniton "Well, you can certainly wear your underwear for thirty days non-stop, but would you really WANT to?;)

Hatterasguy: As a chemical engineer,Purdue, '63, I can assure that no one makes an anti- freeze that I know of that after time turns into acid. Perhaps it turns into rum and maybe MB guys drink it. But not to acid since most cooling systems are closed systems. And not much happens over the years, except people buy new AF thinking that they are cooling their cars with acid or rum, both which can be harmful.

There must be something going on about the properties of radiator fluid that you're not getting.

Every website that deals with radiator fluid says that it becomes corrosive when old.

If you do a google on coolant, you'll get a ton of hits that says that it is corrosive.

Here's one:

http://www.canadiandriver.com/articles/jk/at_001212.htm

It becomes acidic through interaction with the different metals in the engine as the chemicals brake down over time......we use litmis sp? paper to identify when coolant becomes acidic in the shop I work at.

I found a site where "they" say that old AF turns "radio active" if left in your car to long. Other sites are more personal, saying old AF will turn you, the car owner, into a democrat. So what gives?

Feel free to believe that the world is flat.

The whole mainstream automotive world believes that antifreeze becomes corrosive when old.

The onus is on you to prove them wrong.

I can find thousands of sites on Google that back me up.

Here's one section from a Ford website.

"Even though your coolant in your vehicle is green, it may be sending you the wrong signal. Additives to protect the cooling system may have been depleted and the green color remains. Ethylene Glycol (antifreeze/coolant) will turn acidic when buffering ingredients have been depleted, acidic coolant becomes extremely corrosive and components such as the waterpump, cylinder heads and timing chain covers, can become pitted or worn prematurely and lead to costly repairs. That is why your cooling system needs to be power flushed every 2 years or 30,000 miles."

Here's another site:

http://www.molderschoice.com/pdf/Page145BUndilutedEthyleneGlycol.pdf

Acidic corrosion happens when the coolant drops the pH level below 7.0, which happens when there are more positively charged hydrogen ions than negatively charged hydroxide (OH-) ions. Technically, only H30+ (called hydronium) ions exist, because free hydrogen ions quickly combine with H20 molecules to form H30+ ions. The result of this excess is that metal surfaces are corroded with pits as the positive ions rip up and then combine with atoms from metallic and other surfaces.



The pH level is actually defined in an interesting manner. It is defined as the negative log10 of the moles of H30+ ions per liter of water. Water naturally ionizes like this: H20 -> H30+ + OH- about once for every 107 molecules. So, in one mole of pure water, there is about 10-7 moles of H30+. The more H30+ ions you have, the lower the pH level becomes. The pH scale of 0...14 relies on the fact that the product of H30+ and OH- concentrations is always 10-14. If you are interested in a bit more detail, try this page on pH Scale. There are some details here that a doctorate in chemistry (such as our staff member pHaestus) could share, but, thankfully, those details are mostly irrelevant to our discussion.

Moles of Hydronium Ions in One Mole of Water
pH Level

100 Moles = 1.0
0 - Perfect Acid

10-1 Moles = 0.1
1 - Very Acidic

10-2 Moles = 0.01
2 - Lemon juice

10-4 Moles = 0.0001
4 - Wine

10-7 Moles = 0.0000001
7 - Neutral (neither acidic or basic)

10-10 Moles = 0.0000000001
10 - Detergent for Washing Clothes

10-12.5 Moles = 0.00000000000032
12.5 - Household Bleach

10-14 Moles = 0.00000000000001
14 - Perfect Base


In theory, you will see corrosion start when the pH level drops below 7.0. However, copper and aluminum will typically form a thin hydroxide coating that is stable until pH levels drop below 4 or 5. To complicate matters, however, you can go too far in the other direction too. Making the coolant too basic (called an alkaline pH level) can cause corrosion too. A strong base can strip the protective aluminum hydroxide layer that forms on an aluminum surface nearly as easily as a strong acid. And in situations where metal oxide coatings do not form, a strong base can actually be even more corrosive to elemental solid than an acid.

Coolants typically perform best when the pH level is from 9.0 to 11.0. As the coolant ages, it becomes more acidic and starts attacking the metal surfaces, so manufacturers add buffering chemicals. These buffering chemicals (usually borates and phosphates) absorb the acidity as it forms, preserving the safety of the coolant. The buffering capacity of a solution is known as alkalinity. You do not need buffering chemicals if you change your coolant before it becomes too acidic, and many cheaper brands of antifreeze-style coolant skip the buffering chemicals to save money.

has anyone been amused by Porsche's coolant `fill for life ` recommendation?

Yeah right... given best performing Porsches were air-cooled and atmospheric air can be replaced only by moving away:D ;) :p

~Nautilus

28 years ago I bought a new Chevy Blazer. To date, I have never changed the radiator and did however change the AF 16 years ago. The Blazer has a new body, mostly, on it and about 150K miles. So when should I change the acid/caustic AF along with the radiator? I am confused as this truck runs perfectly as it was like new. Perhaps Chevy really knows their stuff when it come to radiators. What say you?

Good for you, Peter.... but I would say your experience is the exception, not the rule. I've bought many a used (5 year old) car where the coolant was never changed and brown in color, only to fail a bit later from corrosion rot.

I have seen data from Ford Motor Co where they plot corrosion protection versus miles for the green stuff. Right at 30,000 miles it crosses the corrosion threshhold.

Strange I missed this post.

It's also strange how some folk get away without maintaining anything. I have a college buddy that was/is that way. He can take a car and universally wear it out having almost no problems until it is a useless POS after 10 years. Since I have know him he has done that to two MBs and a couple Nissans. Other than never maintaining a car, he is probably gentler with it than any one I know outside my dad.

Such stories can be interesting because they are UNUSUAL. I decided years ago that he got such use out of his cars only due to his inordinate ease of use (He slows up as he aproaches green lights - I can't ride with him as he drives me nuts).

Anyway, for those who enjoy their cars and aren't up for Russian Roulette, factory procedures are a good place to start with any personal modifications.

As it turns out I know a bit about corrosion (BS Metallurgical Engineering UofF 1974). Basically it isn't the antifreeze that makes the acid it is the water. It WILL happen unless the antifreeze stops it. The way it stops it is the basis for differences in coolants as everything we have talked about is ethylene glycol. It is the corrosion inhibiting package that changes. Original "green" coolant used phosphate and silicate ions to tie up the process. It turns out that these ions find something to grab onto and plate out as solids over time. It turns out that the corrosion properties aren't linearly related to the ion concentration. It takes some level for them to work and it just stops beneath that level. Thus one doesn't need to get it all out if one changes it regularly adding to the package enough to maintain that threshold.

It turns out that the solids eventually plug raditors and the ions used turn out to embrittle many plastic and rubber components, including hoses, radiators, and waterpump seals. As a result a different technology was created called OATS, organic acid technology. These huge organic molecules somehow protect the metal from corrosion and unlike their name the mixture is stabilized to a "basic" mixture of pH 7.5-11, see:
http://www.valvoline.com/pages/products/product_detail.asp?product=10

The key to making all these antifreezes work is the right amount of additive package in the system. This is the only reason you can mix them. If you had 25% oats and 25% ions and 50% water you would have too dissimilar additive pachages that would not help each other and thus both wouldn't work.

These OATs or HOATs (add hybrid) are all low silicate low phosphate. Almost all are "No phosphates" but G05 has in the area of 250ppm silicates and thus the difference between it and the 5/150 coolants (Dexcool) which have "No silicates"

As a sidebar some Jappanese cars are using water pump seals that are quickly embrittled by even low silicate coolants and require "no silicate" compounds. as such it is common for good maintenance with improper coolant to result in a waterpump failure about a year later.

Common sense from the "modern Mordor" which Romania is:

All fluids are far damn cheaper than rubber & plastic parts, and light years away from the cost of major parts, leave aside the labor costs. For this reason, fluid change intervals recommended by factory have to be attended. And a proverb says "you can't foresee from where will the rabbit jump" - the radiator may live for a quarter of a century like new, yet water pump gasket (or, God forbid, cylinder head gasket) can go to hell when you expect less. Or a hose, for the matter.

That's why here we change coolants each spring & autumn, adding 50% AF in the autumn and less or not at all in spring, flush the brake fluid when it becomes black, change the oil & oil filter when specified, add oil additives after a number of oil changes, complete power steering fluid when low etc. Better give a few bucks away than risk a $5,000 engine rebuild.

BTW there was a story (urban legend?) on Tori Spelling, who was seen pouring a $6 bottle of mineral water in the radiator of an E30 series BMW. Given the risk of an overheating in Californian weather, I understand her... just that I use distilled water on my M-B :D

~Best regards,

Nautilus

Mercedes Antifreeze clones
 

I'm sure everyone has seen the Xerex G05 that is supposed to be a Mercedes golden coolant equivalent. But yesterday at the parts store I see Prestone has finally jumped on the bandwagon with something similar to G05 !! How confusing to the average joe. Prestone makes the normal green, low toxic, dexcool (orange) and now this new stuff.

It seems to me that everyone knows the problem (acid) but no one has told how the average person can test for this acid. Well, here is a little trick I learned a few months ago. Set a digital meter to mv and put the positive probe in the coolent and the negative probe to ground (engine, body or battery). If you get over 300mv (.3v) then change your coolent. If it is under 300mv than everything is fine. I would still change the coolent every 2 years but the DVM trick will help if you forget, or if you aquire a used car and don't know the history of the car.
I didn't believe this at first but after doing some testing on my own cars (some maintained very good and some very bad) I proved to myself that it works.

The litmus test for reserve alkylinity is only valid for conventional "green" antifreeze, so they are not valid for pure organic formulations such as Dexcool, or hybrids like MB brand or Zerex G-05, which is the same formulation as MB brand and approved for all DC vehicles.

Your best bet for coolant system longevity is to replace the antifreeze at the manufacturer's recommended change interval, which is every three years, regardless of mileage, for MBs.

Duke

Paul- thats a cool trick. I am going to have to try that out sometime.

As far as never having a problem for lack of maintaining a vehical,unless you actually take apart the radiator and insepct some internal passages you cant very well verify that its still in great condition. I have seen plenty of ATV's run with the worst looking motor oil you have ever seen. But they still ran, were they running good? Good enough, but surely not what they could be doing with proper oil and change intervals. I guess its just what level of performance you consider acceptable.

Also how do you think you are going to be proved wrong? Most likely on the side of the road with the hood up......

What we have here is a good old fashion peeeeeeeeeeing contest.

Can't we just all get along :D

It's your ride do as you want. I say do as LarryB says change it hot change it often.. Has all this acid talk brought us back to the 60's LOL

MR. LUCKY

This suggests there is credence to the technical merit of this formulation. First Mercedes... then Zerex... now it looks like Prestone doesn't want to miss out on this bandwagon. This formulation may be the everyday antifreeze for all (or most) cars in the future.