Coolant Loss In My Suzuki Motorcycle?

Tips on how to prevent coolant loss.

2009 Suzuki Bandit 1200 ABS
2009 Suzuki Bandit 1200 ABS©Motorcyclist

Question: I recently purchased a 2009 Suzuki Bandit 1250 with about 1,200 miles on it. When I took the bike out for a short ride to warm up the oil before changing it, the temperature light came on. The radiator, which holds 3 quarts, was down 2 quarts. I topped it off and have since put about 400 miles on the bike with no problems or leaks. The radiator fan comes on, so that apparently isn't an issue. Do you have any idea what could have caused the coolant loss?
Joel Widman / via email

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Answer. A seven-year-old bike with only 1,200 miles on it probably sat around unridden for long enough that the previous owner decided a coolant flush was a good idea (and it was) before listing the bike for sale. If you haven't found any leaks, and there's no coolant in the engine oil (it would look pale and watery if there were), then it's possible that whoever replaced the coolant didn't follow the correct procedure. Failure to bleed or "burp" the air out of the cooling system would result in exactly what you're seeing: low coolant level with no apparent cause.

Adding coolant to a motorcycle.
If the coolant level is low and there are no apparent signs of a leak, it’s possible that whoever replaced the coolant didn’t follow the correct procedure.©Motorcyclist

The Suzuki manual says after draining the old coolant through the water-pump outlet hose, reconnect the hose, remove the radiator cap (it's under the gas tank), put the bike on the centerstand, and pour in coolant up to the level of the thermostat connector inlet. Now rock the bike slowly side to side to release air trapped in the cooling system; pour in more coolant to the level of the thermostat inlet. Start the engine, topping off the coolant as the level drops, until no more air comes out. Put the radiator cap back. After warming up and cooling down the engine a few times, add coolant to the specified level on the reservoir bottle.

The cooling system holds 3.2 quarts from empty. If you decide to re-bleed yours, you might want to flush it out with clean water first. If the job wasn’t done right the last time, and it’s likely it wasn’t, this step might have been skipped too.