I have been asked to explain the difference between Dexcool® and clear up some myths and misconceptions about both. This is quite a challenge because every company's antifreezes have different combinations of additives and inhibitors. I won't go into brand specific formulations but rather stick to the basic properties common to all antifreezes.

One myth is that all red antifreezes are Dexcool®. There are standard antifreezes that are red and cars that have Dex cool® will be labeled as such. Another myth is that Dexcool® is not glycol based. Not true, all antifreezes are glycol based, including Dexcool®. Both ethy lene glycol (EG) and propylene glycol (PG) are used as the antifreeze base. From here the additional additives and inhibitors are added. Each glycol has supporters, al though the best choice depends on the intended use. There are several considerations to be made when choosing an antifreeze, the most important being performance. In t he area of performance there is very little difference in EG and PG. Additives determine most performance criteria so all coolants supplied by a respectable manufactur er will perform well. The one major difference in EG and PG is toxicity.

Because the most persuasive reason to use PG instead of EG based antifreeze is toxicity, we should discuss a little about toxicity. The first thing to think about is the difference between acute and chronic toxicity. Acute toxicity refers to toxicity that has a short duration. If you sur vive poisoning with an acute toxin, there are usually no lasting effects. Chronic toxicity on the other hand is something that lasts a long time. When poisoned with a chronic toxin, symptoms may not appear for a long time and they may last indefinitely.

PG differs from EG in both acute and chronic toxicity's. In antifreeze we are most concerned about one time accidental in gestion. Therefore our interest is in acute toxicity. The acute toxicity of PG, especially in humans, is substantially lower than that of EG. Propylene glycol, like al cohol, is not toxic at low levels. In applications where ingestion is a possibility, PG based antifreeze is a prudent choice. EG is the most common base used in the ma nufacturing of antifreeze.