How to replace motorcycle coolant

How to replace motorcycle coolant
This is an overall review of how a water-based motorcycle cooling system works. Special emphasis is placed on how to burp the cooling system so that air pockets in the cooling jacket will be mostly evacuated before the engine overheats. The risk of permanent engine damage from an inadequately burped cooling system are discussed. The mechanism by which the radiator cap works in a closed cooling system is also discussed.

Ethylene glycol, the most common constituent of antifreeze, will last a very long time. However the anti-oxidant additives contained in modern coolants are depleted much more quickly, and harmful impurities can build up in the system and damage sensitive engine parts. So, coolant should be replaced at regular intervals. The 1995 VN800 Vulcan manual calls for replacement of motorcycle coolant every two years.

To understand how the radiator cap draws fluid from the coolant recovery tank into the main cooling system, watch this video.

If you are bewildered by the wide selection of coolants, and worried about mixing different types of coolant, watch the following video.

For a discussion of how an automotive water pump works, and an inside look at the weep hole, watch the following video.

This is an amateur demonstration done for entertainment purposes only. The video comes with no guarantees as to safety or accuracy, and it is NOT a qualified instructional video. Before deciding to work on your own vehicle, search for information from multiple sources and consider involving a professional. Motorcycle repair is a potentially dangerous activity, and complication are to be expected and planned for.

Thunderclap sound used under Creative Commons 3.0 license, done by RHumphries at

34 thoughts on “How to replace motorcycle coolant

  1. thank you so much for the quick respond, i will do the test that you recommended
    thanks again you are awesome

  2. Nicely done. I just did mine on a Vulcan 900 following your instructions. Slightly different locations here and there but was easily able to figure out where everything was. Also noticed some dried up residue around the weephole, guess I’ll have to keep working on it but just glad to see the problem before it becomes a serious issue. Tanks spelunkerd!

  3. The minute I run the motorcycle with the radiator cap off, the coolant wants to squirt out , is that a problem? there seems to be a pressure hole in the left side of the radiator, any answers anyone!

  4. Wow!  Excellent video, I have a 2000 VN800 and I never knew about the cap under the speedo.  I find my fan comes on alot sooner than it should.  Perhaps I need to top off my coolant..  Thanks!

  5. To replace the Thermostat i take it you have to removed the bolts below the cap.. and remove the neck to get at the thermostat yes…

  6. Thank you, very informative and a huge help! I will be doing this to my bike tomorrow!

  7. Thankyou very helpful video iv just bought kawasaki el 250 1991 not sure about cooling system so will use what you showed us on that…

  8. Thanks for another great video. First what I found was the oil change, when I was looking how to change engine oil in my VN800 2004 🙂 I have Haynes manual but I don’t want to remove rear wheel to remove my coolant reservoir… Will stick to your advice and just replace the coolant like you did 🙂 Any advice how to replace fork oil in our vulcans? 🙂

  9. I have a 96 and I think I overfilled the reserve tank because it’s coming out of the small bleeder hole under the cap on the reserve tank? Bought a new cap and diaphragm just in case.

  10. Hi, Thanks for the video, Very helpful, Could you please let me know where that little white bottle with a house on the front left of the rad connects, my one fell and i haven’t a clue where she connects, If you could just make a little video PLEASE, Thanks very much

  11. Have the same bike 2000 thanks for the video been wanting to change mine for some time now.

  12. HELP! washed my bike (05 Kawasaki Vulcan 800classic) and I believe a hose was knocked loose at the bottom because it leaked ALL my gas

  13. This video saved my butt. Had my “96 Vulcan 800 serviced and some clutch work done. Tech forgot to refill coolant. Had the wife out on our anniversary and got a temp light about 50 miles from the house. Stopped at a gas station and watched this vid. Lucky it was cold out and I was two blocks from an Auto Zone. Bought an 8mm wrench, coolant, and funnels. We went to lunch and let the bike cool, then filled it up and we were back on our way. Saved me a tow and an angry wife. Thanks!

  14. why do you need to add coolant/water to the recovery tank? how much do you add?
    it is pretty clear that the whole system needs to be filled up to the top…but the recovery tank? thanks buddy

  15. Thank you for your time, video, and help. People like you help so many of us. Planning on fallowing your instructions for my 2007 1600 Classic. Hope they are still similar. Again. Very much appreciate your work and video help.

  16. Please help. I just drained my coolant and found a good amount of oil. I know you disscused replacing a mechanical seal can you elaborate?

  17. My drain bolt is sheered off completely or it is a non removable plug on my 1998 1500 classic and Clymer wants me to drain it from the rad and the drain plugs on each cylinder. Did you pull the plug from underneath and add a bolt or did it come stock? It looks so much easier on your video.

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