How to Mix Propylene Glycol & Ethylene Glycol

Propylene glycol and ethylene glycol are both used as antifreeze for cars and trucks They are chemically similar in many respects, with propylene glycol considered to be a safer alternative than its ethylene cousin; however, ethylene glycol has better heat transfer properties. Although propylene glycol antifreeze has less coolant ability and is less toxic than ethylene glycol, mixing them won't lessen toxicity or have a major effect on cooling ability.

Things You'll Need

• Ethylene glycol antifreeze in 1 gallon container
• Propylene glycol antifreeze in 1 gallon container
• 5 gallon bucket
• Fresh water, distilled is preferred

Instructions

1. Place a 5 gallon bucket on level ground.

2. Pour propylene glycol into the bucket, emptying only half of the 1 gallon container into it.

3. Pour half the ethylene glycol into the bucket.

4. Add in approximately 1 gallon of fresh water, using distilled water as an ideal choice.

5. Pour this 50/50 mixture into your radiator or automotive/truck overflow tank until full.

Tips & Warnings

• You can also pour each of them directly into your radiator or overflow tank, but trying to estimate a 50/50 water and antifreeze mix is a bit more difficult this way. No harm will come to your cooling system by mixing these two types of antifreeze together.

• If pouring these glycols into your radiator directly, NEVER open the radiator or overflow tank when the engine is hot. Splashing and severe scalding may occur when opening a hot cooling system.

References

• Eet Corp Antifreeze FAQ: Can I add propylene glycol based antifreeze to my existing ethylene glycol based antifreeze?
• Peak Antifreeze: E--Can I mix SIERRA Antifreeze with an ethylene glycol based antifreeze?