There has been a lot of concern over what happens if you are using an ELC or a product such as Evans Coolant and you have to top off in a remote location where these products are not readily available. Many of these concerns are unfounded.
"All coolants are based on glycol," says Ulabarro. Only about 3% of the product is the inhibitor package. "All coolants are basically compatible with one another."
But each manufacturer has limits of contamination that, once exceeded, change how you treat the coolant. For example, waterless coolant is less tolerant to contamination. There are no inhibitors to prevent corrosion from water. If the coolant level drops, you can add water to get to your destination, but the cooling system must then be completely drained and refilled. This can be a detriment given the much higher initial coolant price and the capacity of most diesel engine cooling systems.
ELCs allow a level of contamination with other products. "Our limit is 25%," says Ulabarro. "If you have a 12-gal. system and you add more than 3 gal. of another product, you have gotten to the point where you have diluted the inhibitors in an ELC. When you do that, our recommendation is to treat the coolant like it is a conventional coolant and start adding SCAs."
Arcy agrees, adding, "Our coolant can handle up to 15% contamination. It will still cool properly, but you need to treat it as a conventional cooling system and add SCAs."
If there is no danger of freezing, just add water to the ELC, Ulabarro suggests. Then you haven't changed the product. "When you come back to the shop," she continues, "you just adjust your freeze point."
ELC Conversion Fluids
"ELC conversion fluid is 12 times the concentration of extended-life coolant," says Dan Arcy, Shell.
First, the existing coolant has to be tested to make sure it is a candidate for the conversion. The initial test is the freeze point.
"If you have too much water in there, you may as well drop it out and start all over again," says Carmen Ulabarro, Chevron. "You also want to check for the pH. The other thing to check for is nitrite level. If those three parameters are okay, then it's all right to add a conversion inhibitor, in my opinion."
It is simply a matter of draining some coolant and adding the necessary volume of conversion fluid. "If a cooling system is a 12-gal. system, you are going to add 1 gal. of conversion fluid," says Arcy. "You don't have to drain all 12 gal."