Untitled Document

Preventing Head Gasket Coolant Leaks

Created 1/05/2000

Head Gasket Corrosion is a Really Nasty Thing!
Whatever you do, do not neglect your car's cooling system! If your car has green coolant, it needs to be flushed and replaced at least once every other year, or once a year if you do a lot of city driving. This is because its anti-corrosion properties wear out after about one to two years. When this occurs, really nasty stuff can happen. For example, the head gaskets can start corroding from the inside out! This happened to me in late-1999. My car was leaking some coolant from a mysterious location. I'd put stop-leak in it, and that would fix it for maybe 4 months or so. Then finally, one day I noticed a huge puddle of coolant collecting under the car. I popped the hood open, and didn't see the source of the leak. I poured some more coolant in, and decided to start the car. I suddenly saw a small geyser of coolant gushing out of the head gasket. Head gasket work is very labor intensive, the heads, intake manifold, and everything on top of the engine must come off to replace it. The labor is several hundred dollars. Sometimes people sell older cars for next to nothing, or to junkyards, because the labor to replace the head gaskets is so high. It is definitely a good idea to do anything that you can to prevent head gasket problems.


Here's what BAD head gaskets look like. See where the head gasket has corroded away the coolant passages on the right? It caused a rather nasty external coolant leak. Both head gaskets were in equally poor condition. Click on the image to see more detail.	This is an example of what head gaskets are supposed to look like!

If you have orange (Dex-cool) coolant, you don't have to flush and replace your coolant for up to 5 years. What I recommend if you have the standard green coolant, is to switch over to Dex-cool. Dex-cool is used from the factory on all GM cars since the 1996 model year.

Dex-cool is an OAT (Organic Acid Technology) type coolant, and is designed to have much better anti-corrosion properties than standard silicated (green) coolant. Dex-cool is bright reddish-orange in color, and should not be mixed with green silicated coolant. To switch to Dex-cool in a pre-1996 car, you need to do a complete flush of the cooling system. Then you should use distilled water in a 50-50 mixture with Dex-cool. Distilled water may not be absolutely necessary, but there have been rumors saying that Dex-cool has a high sodium content, while some tap water has a high chlorine content. Sodium+Chlorine=Sodium Chloride (NaCl), and Sodium Chloride is SALT.

As for what type of Dex-cool to buy, I would recommend any of the real Dex-cool type coolants designed by Texaco. They will have the Texaco logo on the bottle. The true Dex-cool is currently sold by GM and also by Havoline. I have been told "Dex-cool compatible" coolants are not the same, and not as good. This includes Prestone 5/150 coolant.