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Can You Put Water In An ATV Radiator? (Mistakes to avoid)

Nothing wreaks your trail riding fun like an overheating ATV, and without spare coolant, it’s a real worry.

You may put water in an ATV radiator as a short-term measure. However, water doesn’t contain anti-freezing, anti-corrosion, or cooling agents, and so long-term use risks the health of your ATV engine.

In this post, you’ll learn why straight water in your ATV radiator can cause some real damage. You’ll also learn how to check coolant condition.

Straight Water Damage

You already know you can use water in your coolant system if you are in a pinch. But leaving it their long term causes some real problems. Boiling your engine risks blowing the engine, damaging the cylinder head, blowing head gaskets, radiators, etc.

Allowing your coolant to freeze can also cause some expensive problems. Cracked engine blocks, cylinder heads, busted radiators. All at-risk and all are a needless expense. Coolant/antifreeze is specially formulated to have a high boiling point a low freezing point.

ATV coolant pump

But your coolant does so much more than that. It contains lubricates that help protects your water pump and thermostat, and seals.

Coolant also helps prevent corrosion inside your engine. Water in a coolant system long-term would corrode these components and the inside of your engine.

Coolant Condition

Coolant should be changed at least every three years. If it’s been longer or your ATV has been running water, I would do a complete back system flush replace the thermostat, and fill it with fresh coolant. Old coolant loses its ability to protect, but it also turns acidic, and that’s a silent killer.

Acid coolant will happily eat the inside of your system, rubber, plastic, and your engine too. So having coolant is important, but having fresh coolant is just as important. Changing every 2-3 years will prevent any risk of acid damage.

ATV coolant tester

A bike that constantly uses coolant likely has a leak. Use a coolant system pressure tester to check the complete system.

Common causes of coolant loss, include:

  • Bad rad cap
  • Cracked radiator
  • Loose hose clamp
  • Leaking water pump

Checking Coolant

You can check coolant strength using a refractometer or dip strips, and that will tell you how strong the mix is very useful info. You can also check the acidity of the coolant using a simple DVOM (Digital Volt Ohm Meter). The acidity carries a voltage charge which we can measure.

Set your meter to 5 volts dc and place the black probe on the chassis ground and the positive probe tip into the coolant. A reading close to 1 indicates you need a flush and a change of fluid. But if you haven’t changed the coolant in three years, it’s time to change it.

Coolant System

Your coolant system is very important for keeping your motor cool. Without it, your engine would get so hot, the internals simply fuses together.

The components of a regular coolant system include:

  • Radiator – transfers coolant heat to the atmosphere
  • Rad cap – regulates the pressure of the system
  • Expansion tank – coolant reservoir
  • Water pump – moves the coolant around the system
  • Thermostat – helps warm the engine quickly
  • Thermoswitch – senses temperature and turns on the fan
  • Temp sensor – senses coolant temperature and sends info temp gauge
  • Temp gauge – shows the temperature of the coolant
  • Radiator fan – electric fan used to help cool the system
  • Engine jackets – coolant passageways throughout the engine
  • Frost plugs – plugs installed in the engine wall that helps prevent frost damage
  • Coolant – coolant/antifreeze liquid used to protect from frost and heat

The coolant system is a sealed pressurized system, and your radiator cap helps regulate the pressure. A pressurized system is a real advantage because it raises the boiling point of the fluid. A sealed system is therefore critical to keeping your engine cool.

You may also find the following posts helpful:

How often should I service an ATV?

Ride the bike without coolant

ATV coolant in oil

ATV coolant in the cylinder