Tesla Branded g48 coolant?!!!!

[Promedic]

I use BASF Glysantin G48, but I don´t know if it`s availible in the USA.

[fred_dot_u]

I've read quite a few posts that appear with the search g48 coolant, but none of them address the concentration. A local auto parts shop has the stuff, described as fifty-fifty but another shop of the same name has the full strength coolant.

Which one should be used in the HV battery reservoir? The DU reservoir is sitting at the top of the marks, while the HV pack is far too low.

[asavage]

Generically, the difference between pre-mix and concentrate is convenience: with concentrate, you do your own mix-down, and you have to source your own DI water (I use distilled, because I stock it for other purposes, and it's readily available, but if you like DeIonized water, it can be had).

Personally, I buy and use concentrate, but pre-mix is more convenient (at a slight increase in cost). One thing you can't do with pre-mix is adjust concentration richer, which is something I used to frequently need to do when I flushed cooling systems, because all the old coolant (or flush water) does not leave the cooling system. With repeated fill/run/flush cycles, I could obtain a clear waste stream, but not a completely dry system. In that situation, being able to use a 40/60 (or whatever) water/coolant mix could get the overall system back to approximately 50/50.

The reason for 50/50? Less concentrate throws off the additive mix, and a weak mix can also raise the freezing point (and lower the boiling point), two of the goals of coolant in ICEs. Too much concentrate decreases pumping efficiency and heat transfer (among other things).

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Tony Williams has stated that coolant test strips that test the pH of the coolant can be used to determine coolant suitability, but I do not agree; that test methodology is valid for ICEs because they have specific coolant degradation patterns, which include accelerated pH decrease, primarily due to extensive dissimilar metals, thermal cycling well above what we have in our systems, and most importantly: pH decrease due to combustion gases leakage into the cooling system, which moves the pH down into the acidic range very effectively (same issue with pH in ICE lubricating oils, BTW, and the reason behind testing used engine oil for residual alkalinity . . . but I digress; Google "oil TBN" for more info.).

EV coolant isn't subject to the same stresses as ICE coolant, and test procedures should be different too. Personally, the stuff is cheap, and if the dealer doesn't gouge too much, I don't sweat it. I got my last coolant changes "free" due to warranty DU replacement @ 60k and warranty battery replacement @ 93k. I just turned over 106k, and I'm nowhere near 5 years since the battery change, so I'm OK for a while yet, and I've cheated and obtained a (hacked) Tesla Powertrain Diagnostic setup, so I can let it open the various valves and run the pumps while I change the coolant myself. It wasn't cheap, and is probably not worth the expense & hassle for most people, who just want to drive their car.

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I can't let this one slide . . .

Neither one is going to corrode. You don’t have to bargain hunt but you can be an aware consumer. These two fluids are one molecule different. One is safe to drink the other is not. The only difference. They both do the same exact job.

One molecule different doesn't seem like much to you? Water (H20) and hydrogen peroxide (H2O2) have pretty different characteristics, too

Arguing that "only one molecule different" makes something essentially equivalent for any particular use is groundless.

[fred_dot_u]

Thank you for the timely reply. As part of the charger diagnosis, I discovered that the battery coolant reservoir was below Low. Your answer allowed me the confidence to purchase the 50/50 stuff moments ago and bring the levels to normal. The diagnosis revealed a pump related error and this may provide for a more certain resolution to that specific problem. It's not THE answer to the charging trouble, but may be the answer to the panic-inducing message on the dash while underway.

The problem with my wife's car is still under diagnosis, no certain solution/problem identified, but this minor incident also had me checking my Rav4EV to discover an equally low level.

[Johan]

Tony Williams has stated that coolant test strips that test the pH of the coolant can be used to determine coolant suitability, but I do not agree; that test methodology is valid for ICEs because they have specific coolant degradation patterns, which include accelerated pH decrease, primarily due to extensive dissimilar metals, thermal cycling well above what we have in our systems, and most importantly: pH decrease due to combustion gases leakage into the cooling system, which moves the pH down into the acidic range very effectively (same issue with pH in ICE lubricating oils, BTW, and the reason behind testing used engine oil for residual alkalinity . . . but I digress; Google "oil TBN" for more info.).

EV coolant isn't subject to the same stresses as ICE coolant, and test procedures should be different too. Personally, the stuff is cheap, and if the dealer doesn't gouge too much, I don't sweat it. I got my last coolant changes "free" due to warranty DU replacement @ 60k and warranty battery replacement @ 93k. I just turned over 106k, and I'm nowhere near 5 years since the battery change, so I'm OK for a while yet, and I've cheated and obtained a (hacked) Tesla Powertrain Diagnostic setup, so I can let it open the various valves and run the pumps while I change the coolant myself. It wasn't cheap, and is probably not worth the expense & hassle for most people, who just want to drive their car.

About additives: Take silicate, to start with. Silicate additives protect (somewhat) against corrosion by (temporarily) "coating metal surfaces" according to coolant manufacturers. Sounds good, right...but wait: Does this also happen at room temperature or does it need "internal-combustion-engine-level" temperatures to trigger this deposition behavior? Batteries get max 55°C when fast charging according to user a report on TMC. Is there a youtube video of website showing that coating actually takes place at such low temperatures? Silicate-based additives are prominently showcased as (temporary) head-gasket crack fillers, crystallyzing only at high temperatures while the water locally evaporates into the cylinder. So at this point I am not yet convinced that any of the additives perform the same as in ICE systems. Besides, many additives are "proprierary", and if not, the chemical formula can be pretty exotic, see for example the text surrounding the coolant lawsuit on Wikipedia, making it difficult to verify.