My radiator is low on coolant but does not pick up fluid from the reservor, the resorvor is still full.
has anyone else had this problem or know what might cause it?
Also what is the best way to flush the radiator, I noticed some trash in it around the neck.
there is a small black hose that goes from the radiator neck to the overflow bottle. check that hose for cracks/breaks and debris. see if you can take it off and blow through it. it may be plugged up. that hose not only acts as an overflow to the overflow tank, but also will siphon out what is needed to fill the radiator. this happens after running the bike and when it cools down, it will create a vacuum and draw back coolant until the radiator is full. if you take off the radiator cap when cool and the level of coolant is low, you need to add it it. vacuum only works so far, and if the level is too low, it will not be able to lift it. 50-50 mix, top off while cold. ride around for awhile. check level when cool or next day. level should be full. your radiator cap seal could also be suspect. maybe the cap is not sealing correctly and not allowing a vacuum to form to draw the fluid up. hope this helps.
Thanks for the info, think I'm going to flush the radiator, and then add new coolant and see what happens.
If your cap is damaged it will pull air around the seal and not through the vent/overflow tube. It will therefore push fluid out through the tube to the reservoir and draw back air from around the cap.
I saw this a lot when the reservoir/overflow tanks first started showing up.
The first car I had with an overflow on it was a '66 Spitfire. I always had enough fluid in the "overflow" to refill the radiator. It was a couple of years before someone pointed out to me that the fluid was supposed to travel BOTH directions in the overflow tube. :shock: :oops:
I replaced my cap. Problem solved.