High silicate coolant for aluminum protection?

[kschachn]

Coolants are so much better than they were years ago.

 

[nthach]

I believe the reason the German OEM's dislike Phosphates is because the water in Europe has a very high mineral content, and when mixed with phosphates they can produce minerals that settle out and cause corrosion. This is why its especially important to use only distilled water with PHOAT's - so this doesn't happen. Most of the OEM packaged PHOAT's come already mixed to ensure this is not an issue.

there’s a new BASF G-code SiPHOAT that VW is using, along with Volvo.

Prestone used to never have a water recommendation - but the latest Cor-Guard formulations have a statement on the back label that “Water Quality Matters. Use only distilled water/good quality water” on the concentrate bottles.

 

[nthach]

AFAIK, silicates were a part of old-school green for quick protection of aluminum and other cooling system metals via coating them. The problem is that silicates don’t hold up to cavitation - which is why diesels get a SCA.

The Japanese saw phosphates and a small amount of an organic acid was the way to provide quick protection while the organic acid passivated certain metals. The Europeans augmented silicate with OAT.

 

[Jake_J]

Silicate is still the best inhibitor for aluminium, it acts quickly and is very effective, the Silicate passivated the aluminium, it partially "absorbs" the Silicate, the bad part is that the Silicate depletes relatively quickly and can gel, although the problems with gelling have been more or less figured out now.

I don't know about it being the best. There's many millions of cars on the road with modern all aluminum engines and heating & cooling systems that contain no silicates and they work great (and they don't have to worry about the silicates precipitating out). The fact that the European and American manufactures as now adding phoshopate to their Si-OAT and OAT formulas while the Asian P-OAT's aren't changing would mean that perhaps silicate isn't quite the best.

 

[Torrid]

I don’t think most of them around here get shut down long enough to freeze. An engineer told me they have an auto start feature when they’re parked in a siding and if air pressure drops to a certain point they start up to rebuild pressure. I don’t know if that’s true but I do recall seeing one parked on a side track near the house running with nobody around.

Yep, that's correct. It's known as Smart Start. They're set to start if the brake pipe pressure drops below 60 psi or water temperature for the engine drops below 100 degrees. Some have a separate generator that starts to charge the batteries and cycle water to heat it and keep it from freezing. The reason why coolant isn't used is because it becomes an EPA paperwork nightmare when it leaks and for older engines they don't really fix leaks unless it's more than requiring it to be filled more than once a week.

 

[VWingAUDIbrit]

So it's been well discussed that GM1825M is a high silicate formulation. The owner's manuals of Toyota Matix cars state that you should use only GM1825M. The cars shipped with pink or red coolant, but history of this post says all GM1825M products are green. Hybrid and Electric vehicles show massive benefits from using high silicate formulations. VW TL 774-L MAN 324 Si-OAT evo BMW LC-19 Cummins 14603 all use a pink version of high stabilized silicate free of phosphates, nitrates, amines, and borates. That being said it looks like silicates in Zerex HT-12 is 220 diluted ppm when diluted and does not meet GM1825M. G-05 silicate is <240 ppm diluted and the PI-Sheet and states it meets or exceeds GM1825M. Both coolants also meet JIS K2234:2006. They both meet ATSM D3306 and D6210, but the euro coolant is missing D4985 in some brands and present in other brands? G-05 meets lots of diesel specs that Euro-Evo does not. Here are lots of interesting notes/food for thought. GM could have added Silicates after production on only their vehicles. Volkswagen started doing this in the mid-2010 era when they were still using previous TL 774 specs by adding silicate pods to the coolant reservoir (Most cars I've worked on post 2014 have one or two pods in the coolant reservoir). Zerex Asian Vehicle (red or blue same formulation) as well as Dexcool are Silicate Free. Zerex HT-12 Green is the same formulation dyed differently. Zerex G48 (Euro blue) used in Volvo BMW Tesla meets GM1825 and Silicates are 250 Diluted. Zerex Original Green meets GM1825M has silicate number of 250 diluted appears to only have Silicates added with no phosphates, nitrates, amines, and borates. The most interesting is Zerex Heavy Duty Extended Life Coolant (Zerex HD ELC) which meets GM1825M and is dyed red and appears to have no silicates but may be hidden in the patents. Zerex Pre-charge Heavy Duty dyed green meets GM1825M and has a silicate number of <250 and no minimum number. So you can find red GM1825 on a shelf because the product exists. The newest formulation that comes close to GM1825M is the Euro Evo (red/pink) but doesn't meet GM1825M but would be the most advanced formulation. Zerex G-05 has a really high silicate count (higher than everything else with a minimum number of 252 but the total number of <240 on the PI sheet doesn't make sense. Both statements cannot be true at the same time unless the first number was not diluted, and the second number is diluted. The PI Sheets are all available at the following link. Valvoline PI Sheets Goodluck everyone and if you want my honest opinion, any coolant mentioned in this document would protect the cooling system just fine. If you want silicate in your coolant maybe you can acquire a silicate pod like Volkswagen used and drop it into the Asian Red formula or the Dexcool Formula. All of the formulations will only offer maximum protection with distilled water (it's a requirement for the long life of these coolants).

 

[JDenyer232]

The current G12 Evo coolant that VW uses has about 500ppm Silicate, so twice that of G05.

The old G12++ and G13 also had about 500.

"He who is without oil, shall throw the first rod." Compressions 8:1 "​

I love this quote

 

[kschachn]

I don't know about it being the best. There's many millions of cars on the road with modern all aluminum engines and heating & cooling systems that contain no silicates and they work great (and they don't have to worry about the silicates precipitating out). The fact that the European and American manufactures as now adding phoshopate to their Si-OAT and OAT formulas while the Asian P-OAT's aren't changing would mean that perhaps silicate isn't quite the best.

Agreed. My ancient Sienna and nearly as ancient ECHO I sold never had anything other than standard Toyota coolant. My old Accord has always had Honda Type 2 as well.

My old BMW used BMW coolant (later G48) which was low silicates. All these vehicles have aluminum blocks and heads and I've never seen an issue with any of them in regards to the coolant.