Hi, my name is Marianne. I took my 2004 GMC Sierra pick-up truck to the local gas station for service the other day and the mechanic told me I needed to have my antifreeze changed. I told him to do the service. When I picked up the truck I noticed that the antifreeze was green and not the orange color like the old antifreeze. I asked him about the color and he told me that the green antifreeze was better. I read the owners manual and it said to use the orange antifreeze. With that said did the mechanic use the wrong antifreeze and if so am I in for engine damage in the future. Thanks.
A little history might help clarify the situation. In the early 1980’s Ford was working with antifreeze manufacturers to come up with globalized formulation that did not use silicates. European countries have very hard water and since water is 50% of the antifreeze mix, water quality dramatically affects the overall mix. At the same time, European manufacturers were abandoning phosphate-based technology because phosphates tend to form scale and Japanese manufacturers, were moving away from silicates, which had a problem getting into water pump seals and destroying them.
The first waves of alternative coolants were hybrid types that combined carboxyl and silicate technologies. Ford started using them after extensive durability testing (over 40 million fleet test miles, on every vehicle platform that Ford had) in the early 1980s. At about the same time, Mercedes and VW were also using hybrid type formulations.
From a maintenance point of view, engine antifreeze does break down. For example, ethylene-glycol based products break down and form organic degradation products, which ultimately cause corrosion problems. In engine coolant, problems with corrosion are negated by using some type of buffering agent. Eventually coolant does have a finite life.
It is interesting to note however, that studies show 80% of glycol products produced in the U.S. are not recycled, but leaked out of the vehicle. This would lead one to the conclusion that many cooling systems are being topped off. By adding fresh coolant into the system, you are in some ways effectively extending the life of the coolant.
There is only one universal coolant that all manufacturers can agree on and that is water. The only problem is that water by itself needs a little help. Needless to say, there is a lot of misinformation out there about what happens when you mix coolants.
A lot of the confusion stems from work that was done when carboxyl coolants were introduced. There was one particular American Society of Testing and Materials (ATSM) test that showed that when you mixed the IAT and OAT coolants it showed a higher level of corrosion. Ultimately, it was shown that the particular test was creating a very corrosive environment because the conventional coolant was diluted so much that it became corrosive.
The best advice is to use the same type of coolant that was originally used in the vehicle. This can be easily determined by looking at the fluid requirements chart at ChiltonPRO.com or ChiltonDIY.com. According to industry experts, if you do not know what coolant is in the vehicle and you top-off with the brand of coolant you normally use, nothing bad is going to happen. Only when dilution rates border 50 percent is the effectiveness of each coolants inhibitor package compromised. However, when adding an IAT to an OAT, the recommended coolant change interval will degrade to that of the shorter-life coolant.
When it comes to antifreeze, there's quite a lot of discussion among various sources. Pretty much what it
comes down to is, there's a reason that the vehicle manufacturers formulate antifreeze for
their engines. Some sources maintain that all-purpose solutions won't do any
harm; others say that the additives used in the vehicle manufacturer's antifreeze formulation are necessary for
long-term engine protection.
Check out Jim's blog, "Which Antifreeze is Right for Your Vehicle?"