HD OATs and brass/lead solder

JHZR2

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In my fleet of cars I run a variety of coolants. It’s ok, finding the ”best” and/or running OEM is part of the fun. So I keep Dexcool, G-48, G-05, JD Cool Gard II, and…. ?

In my 445k mile Ram Cummins, I took it over to cool Gard and it’s great. My 265k mile Cummins has automotive green, and I’m thinking that perhaps I could do better. First thought is JD cool Gard II… but I’m also looking at the Cummins fleet guard line. And then I saw peak final charge at WM, and it has the Cummins approval…. So options… they’re a great thing.

here’s the issue… I think my truck has the original heater core, and I think it’s a soldered brass type…. My understanding is that these trucks came with plain green automotive coolant back in the day… but that was 96, now its 2022… the Chrysler green of back then may be somewhat different from say, zerex green today…. So might as well make a better informed decision on modern coolant…

I know @Chris142 has talked about dexcool eating solder in repaired brass radiators. My understanding is that silicate is a best bet, but some other compounds may also help. It seems like from my reading, that it is the 2-EHA that attacks the solder primarily.

JD cool Gard being a HOAT with apparently very good solder protection seems like the obvious choice. This document is pretty detailed:


But I’d like to understand what compounds must be avoided to protect a soldered brass heater core... Besides 2-EHA. And what Hd type OAT coolants, if any, can be trusted around brass and solder…

thanks!
 
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G-05/Premium Gold can definitely be trusted around them, I used it on my old ‘82 300D which had a brass heater core, and on my ‘93 C3500 6.2 diesel, which had the original brass heater core. Otherwise it’s a good question, because OATs became popular after brass radiators pretty much disappeared, Maybe some EC-1 HD users can chime in?
 
G-05/Premium Gold can definitely be trusted around them, I used it on my old ‘82 300D which had a brass heater core, and on my ‘93 C3500 6.2 diesel, which had the original brass heater core. Otherwise it’s a good question, because OATs became popular after brass radiators pretty much disappeared, Maybe some EC-1 HD users can chime in?
Yeah I run G-05 in my w123 diesels. My 82 300cd actually had Rotella ELC in it for years when I first got it, no issues observed…. But I’m not sure they all had brass soldered heater cores…. Certainly radiators we’re Al….
 
My knowledge of chemistry is very weak, but 2EHA comes up most often as a solder killer in other threads. They also mention additives to counteract it. If you think your older Cummins engines came with IAT green in the 90's, then I would think by then they must have already reduced the silicate levels like today's Zerex green. High silicates promoted cavitation in diesels, correct? I also think that back then, they would have spec'ed an SCA additive with the conventional green.

IF I were to move to a long life coolant, I would make sure that it is actually used in vehicles that do indeed have soldered old school coolant components. I.E., I use purple Mopar coolant in my Jeep, but I don't think it has any yellow metal/solder in the cooling system. I've been running Coolgard/Coolgard II in my workplace John Deere tractors for 40 years - they have old school radiators, but not sure about any aluminum. I use IAT Zerex green in my workplace Ford powered generator (brass/copper rad.) because that's what they recommend. I'm too chicken to change.

Just anecdotal information.
 
My knowledge of chemistry is very weak, but 2EHA comes up most often as a solder killer in other threads. They also mention additives to counteract it. If you think your older Cummins engines came with IAT green in the 90's, then I would think by then they must have already reduced the silicate levels like today's Zerex green. High silicates promoted cavitation in diesels, correct? I also think that back then, they would have spec'ed an SCA additive with the conventional green.

IF I were to move to a long life coolant, I would make sure that it is actually used in vehicles that do indeed have soldered old school coolant components. I.E., I use purple Mopar coolant in my Jeep, but I don't think it has any yellow metal/solder in the cooling system. I've been running Coolgard/Coolgard II in my workplace John Deere tractors for 40 years - they have old school radiators, but not sure about any aluminum. I use IAT Zerex green in my workplace Ford powered generator (brass/copper rad.) because that's what they recommend. I'm too chicken to change.

Just anecdotal information.
I’m pretty confident in cool Gard II. I run it in my mixed metal Diesel engines and one of my Cummins trucks, aluminum and solder don’t seem to be an issue with it, see linked paper above. It’s the obvious choice….For the truck in question, obviously the engine just needs a coolant that meets the Cummins spec…. It’s really just the heater core. This isn’t a HD application, it’s a 96 Dodge Ram… that’s why it used whatever Chrysler filled it with from the factory. But I don’t know that’s whats in it now, could be an AMAM with 2-EHA for all i know. Thus the desire to change over, fwiw..

so if say fleetguard compleat is ok, that’s an option, like zeroed original green, like JD, etc…
 
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