Replacing the Coolant on a 2009 ZX-6R

Warning

I am not a mechanic or a representative of Kawasaki or anything else official. This page is only my notes on doing this procedure myself. Although I believe what I have documented here is correct, I make no promises and you do this at your own risk.

Objective

Changing your antifreeze is one of the regular maintenance tasks specified in your service manual. (My manual says every 3 years or 36,000 Km.) Also, if you attend a track day, you may be required to replace your coolant with water to avoid spilling the slippery glycol on the track. The procedure is the same.

In this walk-through we remove the glycol coolant and flush it out of the system, then replace it with water for a track day.

Tools Required

  • Rear stand (recommended)
  • 4mm hex wrench (Allen key)
  • 10mm socket or nut driver
  • 8mm socket and ratchet handle
  • Torque wrench
  • Thin-blade slot screwdriver
  • Small flashlight or inspection lamp
  • Small divided parts container
  • Several 3- to 4- liter plastic pails or containers
  • Clean tap water (if flushing antifreeze)
  • Replacement antifreeze or distilled water
  • Water Wetter (if using water for a track day and their rules permit it)

Difficulties & Warnings

Getting the fairings off involves quite a bit of work and many fasteners, so allow time the first time you attempt this.

Some difficulties with the coolant change could be:

  • Under-tightening (so it falls out) or over-tightening (stripping threads) the water pump drain plug. That’s why a torque wrench is highly recommended.
  • Handling spilled coolant. It’s slippery. It’s very poisonous. Worse, it has a sweet scent that can attract household pets to lap up a spill.
  • Disposal of your used coolant. Your city may have regulations on how to do this.
  • Danger of burns if you remove the radiator cap from a hot engine (don’t).
  • Danger of leaving an air bubble trapped in the system, lowering cooling efficiency.

Procedure

Placing the bike on a rear stand makes this job much easier by holding it level and giving equal access to parts on both sides.
The coolant pump and drain point is on the left side of the bike, just in front of the shift lever.
… and the radiator and coolant reserve tank are on the right side, just in front of where your right knee rests when you are on the bike.
Unfortunately, these openings are covered by the bike’s body work, so start by removing the front fairings from the bike.

Now let’s get familiar with the relevant parts.

On the right hand side of the bike is the radiator cap (circled in yellow here) and the coolant overflow reservoir tank (magenta here).

On the left side of the bike, the coolant pump is just in front of the shift lever.
Look at it closely and you’ll see the drain plug – a hex bolt at the very bottom that sticks out noticeably farther than the other screws that hold the pump to the bike frame.
When we remove the radiator cap some coolant will slop out, so put a plastic container on the ground under the radiator.

Ensure the engine is completely cool, then remove the radiator cap and set it aside.  Don’t remove the radiator cap on a hot engine!

This lets air into the system to make draining easier.

To remove the radiator cap, you turn it counter-clockwise a partial turn until it stops, then press down on it firmly and turn it farther counter-clockwise until it comes free.

Place a second container under the drain point. Be ready to move it quickly as the stream of coolant squirts out quite forcefully at first.

Remove the drain bolt with an 8mm socket.

You might like to take this opportunity to drill a hole through the side of the head of this bolt, to enable it to be safety wired when you reinstall it later. This is not at all necessary, but is a nice touch if you plan to do a lot of track days with your bike (or if you just want it to look like you do).

Catch the spurting coolant,

and let it drain until the flow stops competely.

Replace the drain plug and tighten it just finger-tight (you’ll be removing it again).

You have not yet removed all the coolant from the system.

First, there is probably a substantial amount of coolant in the reservoir tank on the right side of the the bike.
The easy way to remove this is to remove the two mounting screws holding the tank
and turn it upside down, pouring the contents out through the fill hole.
Then remount the tank.  There is still a tiny bit of coolant at the bottom, but this will get rinsed out as we slop water into the tank in the next steps.

If you are just changing your coolant, you can skip these “flush with water” steps and just go down to adding the new coolant.

If you are changing to water for a track day, you need to rinse all the coolant out of the system; there is still quite a lot in there in the various nooks and crannies.

Fill the radiator to the top with clean tap water.

(Note: you must use distilled water to leave in the radiator.  Right now we’re just pouring water through the system to rinse it, and tap water is ok for this.)

Repeat these steps as often as necessary, until the water draining out of the system is clear:

  • Install the drain screw
  • Fill the radiator with clean water
  • Remove the drain screw and let the water drain into a container for disposal.

On my bike it takes about 5-6 flushes before the water is draining out clear.

Finally, drain the reservoir tank again – some water will have slopped into it and diluted the small amount of coolant that was left from the first draining.

Reinstall the drain screw for the last time. Be sure that the soft aluminum washer that goes with this screw is also installed.

Use a torque wrench to bring the screw to the tightness specified in your manual. My service manual calls for a torque of 8.8 Newton-Metres for this screw.

Now we’ll refill the radiator with fresh coolant. Or, if you’re switching to water for a track day, with distilled water.

Most track day organizers forbid Glycol antifreeze and require you to switch to water. However, many will permit you to add “Water Wetter” to the water. This improves the cooling ability of the water somewhat, without being slipperly like Glycol. It makes the water a light pink colour, as shown here.

Fill the radiator to the top with your choice of coolant or distilled water. You will need to pause several times to give the coolant time to flow down into the radiator’s crevices and hoses.

Then also fill the external reservoir tank up to the “F” line with the same coolant. Do this after you fill the radiator, since some of what you are pouring into the radiator will flow through the spill hole into the external reservoir.

Replace the radiator cap, properly tightening it, and the run the engine for a few minutes. Watch the temperature display to confirm it is warming up, and watch for leaks around the radiator and drain screw.

If you need to go back into the radiator, be sure to let the engine cool completely before opening the radiator cap.

If you drilled your radiator drain screw, you can safety wire the screw at this point. Race organizations and higher-end track days may require this (a common rule is that “any screw holding back a liquid must be safety-wired”). And it looks cool.

You’re done, replace the fairings by reversing the procedure above.


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