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trying to change the coolant on my 05 st4s and it wont fill into the system. fairly certain its not blocked, any ideas?
 

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Just changed mine in the 749 today. Flushed system with 2 gallons of distilled water, even purged overflow tank. I had no problems. But you might try filling it with the engine running. I always hold my hand over the radiator fill hole and "burp" the system (with the engine running). And you are filling it via the radiator, not the overflow tank, right. I had a neighbor in Indiana, when I was a kid, come over and ask me for a long thin funnel to fill his oil. Went over to see what the hell he was doing. He was filling the oil in via the dipstick. Also I purged my system with compressed air prior to filling.
Man those engines take forever to drain.
 

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Discussion Starter #3
that's what i thought, but the manual says to fill it via the expansion tank and let it fill into the rest of the system.......guess ill have to mess with it tomorrow...
 

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Another good flushing approach, which I always do, is to do an initial flush with a mix of vinegar and distilled water (I use deionized water). The acid in the vinegar will help to break down any scale build-up without harming the plastic water pump impeller which conventional automotive silicate treatments would. I follow that up with two flushes of fresh distilled or deionized water. Once complete, fill with coolant/water mix. Take the bike for a ride, burp the radiator to get any air pockets out, top off the coolant. Leave the bike overnight with the radiator cap slightly loose so an remaining air bubbles can escape. The next day, top off as necessary, button her up and your done. Perhaps a bit more anal than necessary but that's just me...
 

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Do it on the side stand also. This makes the rad. cap the highest point.
Not sure about the ST3, but the ST2 and ST4S both have "bleed screws" on the flanges that bolt to the side of the jugs. I had to show the DUC mechanic how to use them (after he only got about 1 quart back into my bike). It should take close to an entire gallon...
 

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Via the radiator while burp/squeezing the pump intake hose worked for me. Takes a while though.
 
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