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Wi | The color is just a dye, it means absolutely nothing.
The first major difference is the antifreeze base, propylene glycol or ethylene glycol(Glycerin is added to some as well). Most RV fluid is PG, when it comes to engine coolant, it's only used for environmental reasons. Most engine coolants are EG based as it is somewhat better for the task at hand.
From there, coolants are simply broken down by their inhibitor types/chemistry. There are inorganic acid tech(IAT), organic acid tech(OAT) and hybrids(HOAT). While you can mix 10-20% of a different coolant, it's best to replace like with like.
IAT coolants are the old school stuff that's usually green (color doesn't matter though). The inhibitors they use deplete rapidly and as such they need to be changed often or need to have SCAs added at certain intervals. Almost nothing comes from the factory with these coolants anymore, yet they still dominate the aftermarket.
OAT coolants are the true original long life coolants and very popular lately. They have a very long service life and require no additives, although some do have a booster you can add to extend the life even further. Heavy Duty OATs come in two varieties, Nitrited and Nitrite Free. Nitrite is actually an inorganic inhibitor used for cavitation prevention. Initially the HD OATs all had it, but after John Deere's Cavitation test came out, it showed that OATs perform just fine without nitrite, although at slightly shorter service intervals in some cases (I'm talking 12,000hrs versus 15,000hrs). Nitrite can destroy aluminum when combined with high Temps and high flow rates, two things that are common in modern emissions engines, which is why the majority of engine makers now recommend nitrite free OATs. Cummins is the only major brand I'm aware of that specifically requires nitrites still. Apparently they don't use much aluminum, or they can't design an engine not prone to cavitation (only 1/3 of wet sleeve diesels are), or they simply just don't like change. To be fair though, a portion of the push behind OAT-NF is environmental issues.
HOATs are a mess and are basically irrelevant in the HD sector. A quick note about HOATs though for the automotive sector, European brands favor silicate(phosphate doesn't work well with their hard water) while Asians favor phosphate(silicates are hard on pump seals).
Within this mess are three ASTM standards:
D3306: light duty automotive coolant, not what you want in a wet sleeve diesel unless it meets another standard as well.
D4895: low silicate heavy duty coolant. This type of coolant may need SCAs added to it before use, and at certain intervals thereafter.
D6210: pre-charged HD coolant. You don't need to add anything to this coolant initially, it's ready to use. Some of these coolant will need SCAs added at certain intervals.
Important to note, the ASTM spec is just a small part of determining what you need and can use. It can be very misleading.
What should you use? My vote has always been to go for the long life OAT products. Financially they make more sense in the long run, plus I am lazy and love the fact they require much less service than old IAT coolants. I used to have Delo ELC 50/50(nitrited OAT), but just switched to Delo XLC (their newest nitrite free OAT). I figured that if Cummins was the only one banging on about needing Nitrite, while everyone else has valid points about excluding it(according to ASTM publications), nitrite-free was the way to go, especially given the fact we have far more Euro motors than Cummins motors here, and they're all newer emissions motors.
Regardless of which you use, you still need to emphasize good maintenance. If you use IAT, check the inhibitor levels and add SCAs as needed. If you use an OAT, check for whatever the specific brand you use wants. For any coolant, monitor freeze point, pH, cleanliness and test for electrolysis.
Coolant filters are a useful way to add SCAs to IAT coolants(that's their original main purpose), be careful to avoid overcharging which can lead to inhibitor dropout. If you switch to OAT coolant, buy filters that do not contain additives if you wish to keep the filter. You can also opt to delete it.
If you mix coolants your engine will not explode, your wife won't leave you, your dog won't die and your girlfriend won't end up pregnant. Most of the major coolant OEMs state 10-20% is an acceptable rate for mixing different coolants due to top offs provided you adjust the service interval accordingly.
Cheers. | |
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Need some clarification on antifreeze
