Motorcycle Coolant Change

It's recommended to change the antifreeze (coolant) every two years. It's also recommended to use a special motorcycle antifreeze. In reality, the authors of this article never changed the antifreeze that regularly and often used car concentrate diluted 50/50 with distilled water. This approach was used on a 2005 Yamaha R6 (from 2,000 km to 50,000 km) and a 2003 Honda VFR800 (from 1,000 km to 15,000 km) without consequences. You can draw your own conclusions, or not. In this article we'll look in detail at how to change the antifreeze.

Draining the old coolant

1. The engine should be cold or warm; the main thing is that it isn't hot, so you don't get burned when draining the antifreeze.

2. Open the radiator filler cap so that no vacuum forms in the system and the fluid drains easily.

3. The main drain point on all motorcycles is the drain bolt on the water pump. You can identify it by its copper sealing washer, plus it's the lowest point. So to drain the fluid, unscrew it. When you unscrew the bolt, the flow will be strong, so put a suitable container under it right away.

4. The fluid will drain for a few minutes. It's advisable to rock the motorcycle to empty the system completely. Some motorcycles have drain bolts on the cylinders, which can also be identified by their copper sealing washers. By unscrewing these bolts you can drain another couple of hundred grams. Antifreeze can also remain in the hoses.

5. After the fluid has drained, screw the drain bolt back in. Don't tighten it too hard so you don't strip the thread.

6. Pour the fluid out of the expansion tank. Assess how dirty the tank is. As a rule, there is a deposit on the walls. Rinse the tank with ordinary water.

Flushing the system

Flushing the system is recommended in the following cases:

• You don't know what antifreeze was used. Since not all antifreezes can be mixed, the old one must be completely removed from the system, which requires flushing.

• You don't know when the antifreeze was last changed. If the motorcycle was used or stood for a very long time without an antifreeze change, deposits from oxidation may have formed in the passages and need flushing out.

• There is a lot of dirty deposit in the tank (there is always some, but not much). This means there is dirt in the system that needs washing out.

• If you change the antifreeze regularly and always use the same one, there is no need to flush the system!

Flushing:

1. Distilled water is poured into the radiator up to the filler neck (the whole system fills).

2. The engine is started and warmed up to operating temperature so the fans come on.

3. When the engine cools down, the water is drained from the system.

It's enough to repeat this procedure 2–3 times. When the drained water is colorless, the system is flushed.

Filling the system with new coolant:

1. Make sure the drain bolt is tight.

2. Pour fresh antifreeze into the expansion tank so that the level is between the maximum and minimum marks.

3. Pour antifreeze into the radiator until the level reaches the filler neck.

4. Start the motorcycle and warm it up to operating temperature; it's better to go for a ride.

5. Check the level in the tank and radiator and top up antifreeze if necessary.

Check the antifreeze level again a day or two after the change. It's recommended to check the level every 500–700 km and after crashes. In practice, if there are no leaks, in city use it's enough to top up the fluid once a season.