NoOne65 Posted October 18, 2013 Share Posted October 18, 2013 Just a quick question...if there is no evidence of coolant loss could the cap be the cause of disappearing coolant? J Quote Link to comment Share on other sites More sharing options...
XXBirdSlapper Posted October 18, 2013 Share Posted October 18, 2013 What do you mean by no evidence? The best and fastest way is to pressure test the system. There is, no substitute. 1 Quote Link to comment Share on other sites More sharing options...
IcePrick Posted October 18, 2013 Share Posted October 18, 2013 How much is missing? I'm guessing it is repetitive, e.g. you have filled it a number of times. How low does it get? Let the bike sit overnight, pull the oil dipstick, and look for condensation or even a little emulsification on the stick. A leaking water pump seal can lead to coolant escaping into the crankcase. Could also be a head gasket, but that usually results in flow the other way - exhaust gas into the coolant - you still ultimately lose coolant, though. Could it be a pinhole in the rad or a hose, leaking onto the headers and evaporating? Seen that too... Quote Link to comment Share on other sites More sharing options...
NoOne65 Posted October 19, 2013 Author Share Posted October 19, 2013 yea nothing in oil and no fluid on the ground or the bike itself...ever...but coolant lasts about a week until the gauge starts creeping up Quote Link to comment Share on other sites More sharing options...
redxxrdr Posted October 19, 2013 Share Posted October 19, 2013 Does the overflow bottle fill when hot, then go low when cool? I had crud under the cap seal that would prevent the coolant from returning to the radiator. The overflow bottle would overflow when riding, so I wouldn't see it leaking. Daughters car had same problem, but it was a cap with old stiff seals Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted October 20, 2013 Share Posted October 20, 2013 My thought...pinhole leak in system (probably radiator). I don't have a problem with fluid loss, but when the plastics are off the bike and you let it warm up, you'll see this "puff" of vapor coming from the radiator about where it was repaired/patched, and YES, it keeps passing leak tests. I can only presume you might have a bigger "leak" where fluid is lost in vapor form and doesn't condense on anything with enough quantity to be obvious. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted October 22, 2013 Share Posted October 22, 2013 It's probably leaking somewhere hidden and evaporating. Pull the tank and look at the hoses and stuff behind the motor. Some leaks will only flow cold then seal up as things expand and soften, some only with a hot engine when there's pressure. Quote Link to comment Share on other sites More sharing options...
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