Green Coolant in my 87 MB 300SDL - Page 2 - PeachParts Mercedes-Benz Forum

Shortsguy1 · #16 07-07-2014, 01:37 AM

Quote:

Originally Posted by Skid Row Joe

Please post any independent laboratory findings to back ANY of your claims and suppositions you've written here above?

Uberwasser: Please don't waste your time on this. Your post provided helpful information and it is not your job to justify why Mercedes approves certain fluids and not others.

Maxbumpo · #17 07-07-2014, 08:27 AM

Quote:

Originally Posted by Skid Row Joe

I didn't know there was another coolant (other than green) when I had my 300SD. No problems there that I ever encountered.

I've got an aluminum head from an OM603 with some nice big cavities eroded away at a few places where coolant can stagnate. One cavity gets uncomfortably close to the combustion chamber.

I had a local machine shop examine the head to make sure it was usable. They gave it a passing grade (barely). I asked what the machinist thought about the cause of the cavities. He didn't even hesitate: wrong coolant was used and it attacked the aluminum.

tangofox007 · #18 07-07-2014, 11:13 AM

Quote:

Originally Posted by Maxbumpo

I asked what the machinist thought about the cause of the cavities. He didn't even hesitate: wrong coolant was used and it attacked the aluminum.

Nothing like asking a machinist a chemistry question. But I suppose that any coolant that has exceeded its life expectancy is the wrong coolant.

Maxbumpo · #19 07-07-2014, 11:53 AM

Quote:

Originally Posted by tangofox007

Nothing like asking a machinist a chemistry question. But I suppose that any coolant that has exceeded its life expectancy is the wrong coolant.

Fair enough, but I'll bet any machinist working at a shop that specializes in auto/truck work has more experience in diagnosing what has gone wrong with a head than any chemist I can find.

uberwasser · #20 07-07-2014, 12:04 PM

Quote:

Originally Posted by Skid Row Joe

Please post any independent laboratory findings to back ANY of your claims and suppositions you've written here above?

What, the claim that going beyond the service life of a particular coolant is bad?

Or that using a longer service life coolant can save you money?

Yeah, ok.

My memory may be backwards regarding whether coolant becomes more basic, or more acidic, as time goes by but the main message was that longer service life coolant is designed to remain neutral for much longer. Reducing the likelihood of damaging corrosion overall, unless someone is religious about changing their coolant.

Additionally, as noted, Zerex G-05 is uniquely formulated when compared to all the other coolants covered in the charts I provided. One example - you'll note it's forumlated with nitrites. I just did some basic research and found the following article:

The Basics of Diesel-Engine Coolant | Construction Equipment

Here is an excerpt (feel free to read the rest of the article - it's pretty interesting):

Quote:

Today, the preferred conventional antifreeze for diesel engines is "fully formulated," identified as ASTM D-6210 or RP-329 by the Technology & Maintenance Council (TMC). This antifreeze is sold with an SCA package already blended in, typically including nitrate to protect iron and steel, tolyltriazole to protect copper and brass, borate or phosphate to buffer acids (formed as glycol breaks down), silicate to protect aluminum and nitrite (sometimes accompanied by molybdate) to form a cavitation-resistant barrier on sleeves.

This echos the suggestion on the chart by NAPA that says diesel engines need a coolant with nitrites. It seems, this is to protect against cavitation by protecting the metal with a layer or nitrite.

So while none of the above is an in depth study in to coolant on my part, I think it's enough to make me lean towards sticking with using the generally regarded proper coolant in my engine. Especially since it saves me money in the long run. No brainer.

You can do whatever the heck you like!

uberwasser · #21 07-07-2014, 12:04 PM

Quote:

Originally Posted by Shortsguy1

Uberwasser: Please don't waste your time on this. Your post provided helpful information and it is not your job to justify why Mercedes approves certain fluids and not others.

Thanks. I didn't take that much time to find some relevant info, however.

Mxfrank · #22 07-07-2014, 01:36 PM

Silicates protect aluminum best, nitrites are needed to prevent liner cavitation in Diesels. Mercedes used G05 because it has both. The reason they picked it is that the same formula works well for gas or diesel motors, so the dealer only has to carry one fluid. You can find green coolants that have similar formulations, and most parts stores sell 'fleet coolants" which are premixed for diesel engines. If you use according to the directions on the bottle, they all work.

The problem with silicates is that they are only marginally soluble in water. As the coolant picks up impurities from the engine, they tend to precipitate out. This is why you find sludge and crystals in poorly maintained motors with "green" anti-freeze. And that's why traditional coolants have two year change intervals. G05 is a hybrid antifreeze, which has OAT technology along with low levels of silicate. The "low level" is why it has a longer change interval.

The acid/basic stuff above is mostly wrong. Antifreeze, regardless of formulation, starts out somewhat alkaline due to the additive package. Acids will form in your coolant, both from engine byproducts and from the gradual oxidation of the glycol in the coolant itself. This will bring the PH down. When the reserve alkalinity is consumed, the coolant will be acidic, and will eat away at your engine components. There's no such thing as permanent anti-freeze.

uberwasser · #23 07-07-2014, 01:47 PM

Quote:

Originally Posted by Mxfrank

The acid/basic stuff above is mostly wrong. Antifreeze, regardless of formulation, starts out somewhat alkaline due to the additive package. Acids will form in your coolant, both from engine byproducts and from the gradual oxidation of the glycol in the coolant itself. This will bring the PH down. When the reserve alkalinity is consumed, the coolant will be acidic, and will eat away at your engine components. There's no such thing as permanent anti-freeze.

Thanks for helping to correct this, was going off memory and was incorrect in part, though I believe my point in my second post still stands that despite not having a complete grasp on the chemistry behind it (certainly not my field), the underlying point is that over time the PH changes and this is a negative thing.

Is it untrue that longer service interval coolants have additives to buffer the PH and retain near neutral/slight alkalinity (a ph of approx 8)? Is it only the silicate content that limits service life?

Skid Row Joe · #24 07-07-2014, 04:21 PM

Quote:

Originally Posted by Mxfrank

Silicates protect aluminum best, nitrites are needed to prevent liner cavitation in Diesels. Mercedes used G05 because it has both. The reason they picked it is that the same formula works well for gas or diesel motors, so the dealer only has to carry one fluid. You can find green coolants that have similar formulations, and most parts stores sell 'fleet coolants" which are premixed for diesel engines. If you use according to the directions on the bottle, they all work.

The problem with silicates is that they are only marginally soluble in water. As the coolant picks up impurities from the engine, they tend to precipitate out. This is why you find sludge and crystals in poorly maintained motors with "green" anti-freeze. And that's why traditional coolants have two year change intervals. G05 is a hybrid antifreeze, which has OAT technology along with low levels of silicate. The "low level" is why it has a longer change interval.

The acid/basic stuff above is mostly wrong. Antifreeze, regardless of formulation, starts out somewhat alkaline due to the additive package. Acids will form in your coolant, both from engine byproducts and from the gradual oxidation of the glycol in the coolant itself. This will bring the PH down. When the reserve alkalinity is consumed, the coolant will be acidic, and will eat away at your engine components. There's no such thing as permanent anti-freeze.

This sounds really good, and on the right track for the most part.

Can you link to any published industry research journals of this information, that correlates to, and corroborates what you've written?

Shortsguy1 · #25 07-07-2014, 05:01 PM

Quote:

Originally Posted by Skid Row Joe

Can you link to any published industry research journals of this information, that correlates to, and corroborates what you've written?

SRJ: As you recently were introduced to MS Excel for the first time, perhaps you also haven't heard of Google Scholar. It is a helpful tool for finding published research, so you don't have to rely on others to do your work for you. "Teach a man to fish...."

Skid Row Joe · #26 07-07-2014, 05:24 PM

Quote:

Originally Posted by Maxbumpo

I've got an aluminum head from an OM603 with some nice big cavities eroded away at a few places where coolant can stagnate. One cavity gets uncomfortably close to the combustion chamber.

I had a local machine shop examine the head to make sure it was usable. They gave it a passing grade (barely). I asked what the machinist thought about the cause of the cavities. He didn't even hesitate: wrong coolant was used and it attacked the aluminum.

Not enough information, Bumpo, to come to those conclusions.

Without forensically researching and providing the complete timeline and all facts on your specific instance/story - it may just all be opinion on what may or may not have caused the "nice big cavities," over time. I would ask the machine shop how they ascertained their opinion with such certainty? -Too incomplete to take it as Gospel.

Just how does "coolant stagnate in a few places?" While not in others? Is this something that can be proven as well?

A lot of claims that get written around here "as fact," just isn't corroborated with scientific research to back it up. As I learned by asking that guy above to do. Because some guy at a shop told you one thing or other, it's accepted as fact? Seriously?! Or, someone cut 'n pastes commercial sales ads - that's Gospel......really? Those pass as definitive research for some? The conclusions drawn by some reports here appears in some cases, shooting from one's hip, rather than from doing scientific research done to arrive at them.

If all the disasters written about were across the board then why didn't any of our (6) MB diesels going back to 1969 (with our first new MB diesel) with mega-miles and mega-years of ownership exhibit any failures, regards cooling systems with green stuff?

Shortsguy1 · #27 07-07-2014, 05:41 PM

Quote:

Originally Posted by Skid Row Joe

Just how does "coolant stagnate in a few places?" While not in others? Is this something that can be proven as well?

Um, well, yes. Compare the coolant channels in a om603 block with the coolant channels in a om603 head. Many block channels dead end at the head. Thus, stagnation.

Joe, please put in a little effort yourself here. This is pretty basic stuff which you could figure out for yourself if you spent 5 minutes with Google. Your attempts to derail an intelligent conversation get tiresome.

Mxfrank · #28 07-07-2014, 08:43 PM

Quote:

Originally Posted by uberwasser

Thanks for helping to correct this, was going off memory and was incorrect in part, though I believe my point in my second post still stands that despite not having a complete grasp on the chemistry behind it (certainly not my field), the underlying point is that over time the PH changes and this is a negative thing.

Is it untrue that longer service interval coolants have additives to buffer the PH and retain near neutral/slight alkalinity (a ph of approx 8)? Is it only the silicate content that limits service life?

All commercial coolants are PH buffered. The ideal mix needs to be between PH 4 and 9 for aluminum, but between 9 and 11 for iron and steel. So you can see that there's an inherent problem in an engine with an iron block and an aluminum head, with a mix close to PH 9 being ideal. Anything below 4 will eat both metals. Much above 9 will destroy aluminum, and above 11 will be bad for iron as well. If you maintain your coolant, you'll probably find that the ph is between 7 and 10, which is good enough for government work.

Silicates act differently than other SCA's. They fall out of solution easily as the coolant picks up contamination from the engine. They also coat the engine surfaces aggressively, especially aluminum. If you want to see this in action, fill an aluminum pie plate with a 50/50 green mix and bring it up to 180F. The plate will get a thick coating almost instantly. Because of this, they can simply be used up if the engine is subject to a lot of cavitation erosion. So high silicate anti-freeze has to be changed often.

As for references, I really hate pointing to websites. The group grope comes up with a lot of poor answers, which then become folklore. There is an inexpensive training booklet available on the subject, "Corrosion of the Cooling System" by Clement A Mesa, a former Chrysler engineer. It's available from Technology Transfer Systems http://www.engine-cooling.com/, which of course is down at the moment. If you search the SAE website, I'm sure you can find many papers on the subject, and there are any number of texts available from Amazon.

My two cents: G05 is a great choice. When I can find it, I use it in both the Mercedes and the Jag. But if you simply follow the directions on the label, the green stuff can work.

tjts1 · #29 07-08-2014, 01:00 AM

Quote:

Originally Posted by Maxbumpo

I've got an aluminum head from an OM603 with some nice big cavities eroded away at a few places where coolant can stagnate. One cavity gets uncomfortably close to the combustion chamber.

I had a local machine shop examine the head to make sure it was usable. They gave it a passing grade (barely). I asked what the machinist thought about the cause of the cavities. He didn't even hesitate: wrong coolant was used and it attacked the aluminum.

How often was the coolant changed on this head is the more important question.

Skid Row Joe · #30 07-08-2014, 01:02 AM

Quote:

Originally Posted by Mxfrank

All commercial coolants are PH buffered. The ideal mix needs to be between PH 4 and 9 for aluminum, but between 9 and 11 for iron and steel. So you can see that there's an inherent problem in an engine with an iron block and an aluminum head, with a mix close to PH 9 being ideal. Anything below 4 will eat both metals. Much above 9 will destroy aluminum, and above 11 will be bad for iron as well. If you maintain your coolant, you'll probably find that the ph is between 7 and 10, which is good enough for government work.

Silicates act differently than other SCA's. They fall out of solution easily as the coolant picks up contamination from the engine. They also coat the engine surfaces aggressively, especially aluminum. If you want to see this in action, fill an aluminum pie plate with a 50/50 green mix and bring it up to 180F. The plate will get a thick coating almost instantly. Because of this, they can simply be used up if the engine is subject to a lot of cavitation erosion. So high silicate anti-freeze has to be changed often.

As for references, I really hate pointing to websites. The group grope comes up with a lot of poor answers, which then become folklore. There is an inexpensive training booklet available on the subject, "Corrosion of the Cooling System" by Clement A Mesa, a former Chrysler engineer. It's available from Technology Transfer Systems http://www.engine-cooling.com/, which of course is down at the moment. If you search the SAE website, I'm sure you can find many papers on the subject, and there are any number of texts available from Amazon.

My two cents: G05 is a great choice. When I can find it, I use it in both the Mercedes and the Jag. But if you simply follow the directions on the label, the green stuff can work.

Well.......without sources, (ones that work and can be relied upon as scientifically reliable......) your writings aren't corroborated with the verification I have asked you for in my previous post. There's no way of checking your opinions - regardless how you got them.

Thanks again for sharing your opinion.

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I've noticed that some earlier posts from a day or two ago in this thread are parroting sales-pitch ads, and spouting opinion as if industry doctrine. Well, it's not worth just a lot\ to gain in the way of factual technical data on the subject.