Antifreeze

My question has to do with antifreeze. I have noticed that there are different colors of antifreeze and when I look at the containers it states “can be used with any other types”. I thought each color (yellow, green, orange) all had there own chemical make-up and could not be mixed together due to chemical issues. I looked at my owners and it states use gold (yellow)antifreeze and not to mix with other colors because it could cause premature cooling system failure. Can anyone please help clear up this question for me?

I can’t go into the technical aspects, but I will take a stab at some general rules to follow.

GM and some other manufacturers use “long life” coolant. With those, you don’t ever want to mix them, even with “universal” coolant that says on the label you can mix them with any type of coolant. Others doubt this advice, but I think you are better off safe than sorry.

If you are going to use a coolant other than what is recommended in your owner’s manual, make sure you flush all the old coolant out first, and you should change it every two or three years. I also recommend you wait until your warranty has expired, and if you have any head gasket problems, don’t expect any “good will” repairs from the manufacturer or the dealership.

There are all kinds of stories out there about mixing coolant and long life collant, but the important aspect to consider is the denial of warranty claims. I believe the infamous GM head gasket stories probably involve contamination caused by a leak in the system. Some coolants don’t do well in compromised cooling systems, so if you have a leak, get it fixed right away.

The problem is that mixing coolants and compromised cooling systems might make the coolant acidic, which could lead to head gasket problems. Those can be expensive.

You can mix antifreezes and it won’t cause a problem. But what it does do is effect the corrosion inhibitors. So for example, if you were to add the regular green antifreeze to a cooling system that has what is called one of the long life antifreezes, from that point on the cooling system no longer has the long life antifreeze. And should be serviced at the interval for regular antifreeze.

Also remember, the military purchases all different types of anifreezes from different suppliers. And if there were a problem with mixing different types of antifreezes with others, you can be sure the military wouldn’t purchase it.

Here’s what the brothers say about the subject. http://www.cartalk.com/content/columns/Archive/2000/August/08.html

Tester

When it doubt, use what the manual calls for and nothing else. Even if they claim to be compatible, I doubt that will stand up to scrutiny if a warranty matter is involved. I try to never mix fliuds with different brands due to the potential for additive incompatibility. There’s some bad stories about some coolants going bad all over the internet. Just google ‘death-cool’ for the worst of them.

Well put. This whole Dex-Cool debate can become quite heated, so let’s just say it is unresolved and controversial. Until it is decided one way or the other conclusively, it is better to play it safe.

Thank you for all the information and point of view. I will stay with what the owners manual states. I rather be same than sorry and not have to spend hundreds if not thousands on repairing an engine.Thanks again.