a friend told me that he’d been told by his mechanic that it was very important to stay with the same ‘color’ of coolant when adding antifreeze–that it could harm his car’s engine if he didn’t. I’d never heard of such- any truth in this?


Anti-freeze today is not your grandfather’s of yesterday.
There is some controversy because of the chemical makeup of the various antifreezes and their effect on different cars. Some car manufactures specify a particular brand,usually their own,manly for warranty purposes. You’ll probably get a lot opinions.


Yes, this is true. Blending the wrong antifreezes can produce a gel-like substance in the cooling system. Gel won’t flow like liquid, and the engine won’t be cooled. Disaster ensues.

Stick with the color you have, or change it to another color, but don’t mix them.


It’s a little more complicated than “color,” but you do not want to mix different types of antifreeze. In some cases it may be OK to use a different type after flushing all the old stuff out of the system (not just the radiator). You need to find the manufacturer’s recommendations for your specific engine.


There is a great deal of truth to this, but it is not absolute. If you are simply topping up, use the same color. If you are doing a complete drain and refill, you may switch to any antifreeze approved for your car.

Prestone has dropped its familiar “green stuff” and now sells a popular universal antifreeze that can be used in any car’s system, or so they claim. But again, I recommend you avoid mixing.


I would advice sticking with the same type or if not possible the same color (or do the specific research to find out what kinds/colors are compatible.

However the first thing to do is to check to see what if anything the owner’s manual says. If it sspecifies a type or color, stick with it. not doing so can cause problems.

As noted modern coolants (they are not antifreezes any more) are far more complex that in the old days.


Does anyone know about the Prestone pre-mixed 50-50 antifreeze available in most stores. The label says it can be mixed with any color antifreeze.


There are two basic antifreeze formulas, ethylene glycol and propylene glycol. The ethylene glycol is the most common, but propylene glycol is making inroads because it is safer for animals.

Then there are different detergent and corrosion protection formulas available for both types of antifreeze. About 10 years ago, GM came out with new type of long life corrosion formula called Dexcol. Its color is pink and it’s ethylene glycol with an additive package called OAT. This is not compatible with the older (green colored) formulas.

The new longlife formulas from Prestone, Peak and Zerex are called a HOAT or Hybrid OAT. It is compatible with both the older green coolants and Dexcol. It is available in different colors, and in both ethylene and propylene glycols.

If you are toping up and not sure what you have, you can use any of the brands that say “mixes with all colors” and “long life”. The best thing to do though, especially if you haven’t changed the coolant in awhile is to go ahead and drain the block and radiator and refill with one of these.


An all-purpose might be compatible with some coolants. I would stay away from it in general. The plethora of coolants came when manufacturers moved away from ferrous metal for the engines and copper-solder radiators and heater cores to aluminum and plastic. At the same time they changed water pump seal material. I would try to find exactly what the manufacturer recommends unless you have the ability to analyze the situation carefully.