More Information for PRESTONE 71621
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PRESTONE 71621  
Out of Stock
(Type: Concentrated)
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PRESTONE 71621 Specifications
Boiling Point at 50 50 Mixture229 FA
Ethylene GlycolYes
Flash Point220 FA
Freezing Point-34 FA
Phosphate FreeYes
Recommended Dilution Ratio (Concentrate Option)5 to 7
All Vehicles - 10yr/300k mi - Concentrate
Prediluted formula contains 50% distilled or deionized water, mixed with 50% full-strength concentrate, making it ready-to-use straight from the bottle.

Concentrated formula contains 100% full-strength concentrate, and must be mixed with the recommended ratio and type of water (typically distilled or deionized) before use.
Coolant / Antifreeze Says a lot about Cooling System Health!

Routinely inspect your Coolant / Antifreeze with these simple checks, and flush the system when necessary, to help prolong the life of your Cooling System:


Coolant should be bright, clear and free of debris. Dirty or brown coolant can be caused by:

  • A blown Cylinder Head Gasket
  • Corrosion from imbalanced coolant chemistry
Oil Coolant
Oil in Coolant

Use Coolant / Antifreeze Test Strips to test condition / chemistry. Poor coolant condition can be caused by:

  • Frequently topping off with water
  • Improper dilution / mixing coolant formulas
Coolant Test Strip
Test Strip Process

Use an Electrical Tester to Test Coolant for Electrolysis. Common causes of Electrolysis include:
  • Stray electrical current from a loose or damaged Battery Cable ground
  • Worn / old, acidic coolant
Electrical Tester
A reading of 0.4 volts or above
suggests electrolysis

Importance of Routine Cooling System Maintenance

Prestone® Helps Avoid Costly Repairs

Additional Resources

Material Safety Data Sheet (MSDS)
Antifreeze is recyclable! Many towns have free waste drop-off sites, which a quick internet search will help you find.

Attention California Customers - WARNING: Reproductive Harm -