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Leaking coolant

11K views 22 replies 11 participants last post by  Hot Cruiser 
#1 ·
My bike had been seating for almost a week and today I found around 7 drops of coolant under my bike, I guess under the coolant container. I am new to bikes. What areas should I inspect and check if they are tight enough? Thanks for your help.
 
#5 ·
just a thought but here's a guess, when rad fluid got hot and expanded into #8 there in the pic the rad reservoir tank, maybe the tank got too full and overflowed a bit of rad fluid when you were done your ride last week
 
#8 ·
does the 900 rad fluid reservoir tank have a see-thru plastic side tube on it? maybe check to see what level the rad fluid is at inside that tank
 
#9 ·
The over flow tank is a clear(cloudy) plastic. It can be viewed from the left side of the bike from the rear, about 10-12" off the ground. That or take the left side cover off along with the chrome plated plastic piece under that to see the tank and hose. A bit of a PITA.
 
#11 ·
when the rad fluid and bike are cold, should the recommended rad fluid level on tube be at the upper Full line or at the lower Low line, I can never remember which is recommended so I usually make my reservoir tank level half-way between F and L when bike is cold
 
#13 ·
hugo said recovery tank level is almost at upper line so maybe there are no loose clamps for a leak, maybe the rad fluid just overflowed the top
 
#14 ·
The VN900 shop manual says that coolant should be checked when the engine and system are cool, and then the coolant level in the overflow tank should be at the Full mark. When I've changed the coolant I've refilled the system to that level and thankfully so far there has been no sign of leakage or dripping coolant.

There can be confusion as with cars, etc. coolant checks when the system and engine are cool ordinarily should be at the Low mark on the overflow tank.
 
#16 ·
@hugo0612
Have you checked the drainage outlet passage? if it is wet in that passage -using a flashlight, I would stick a paper towel and see if more is coming out... I have experienced in the past a few drops coming from there after riding it >4000 RPM.

blue paper towel wrapped around suspected areas can help in detecting the actual leak.
 
#19 ·
I like that paper towel idea, to seek out the source of the rad fluid drops
 
#20 ·
Kaw fixed a visible gasket leak when my new 12 Nomad leaked. A year later I smelled a leak when hot & running hard, but lost little fluid. This year lifting the tank to install saddle heat shields, I found crusted stuff (alot) ftom a small leak that had crusted up at a hose & sealed itself. I snuggled up the clamp & wiped off the crud. Mystery solved.

Sent from my SM-G900V using Tapatalk
 
#21 · (Edited)
Check to see if it holds pressure. If the radiator cap (not on the radiator, under the fuel tank) is not sealed properly the fluid boils and blows out the reservoir over flow. It's hard to get the cap to reseal if you take it off for inspection or to change the antifreeze. To check if it holds pressure, warm the bike up by letting it idle about 15 minutes. Reach down and squeeze the radiator hose to see if it has pressure. It should be really firm. To compare, squeeze it when it's cold first. If it's not making pressure, take the tank off, pull the reservoir hose off and blow some air in the pipe your removed reservoir hose from. The shop manual says it will stand about 19 pounds air pressure but for test purposes you don't need near that much. And, I really don't recommend that much pressure either. About 5 pounds is plenty. In my case, 5 pounds of air was enough to re-seat the seal. Of course, if your not a cheapskate like I am, you can just replace the cap.
 
#22 ·
I discovered a coolant leak and thought that it may have been the upper hose/hose clap to the thermostat housing. So I got ambitious and removed the fuel tank (of course I just filled it up right before I saw the leak) to trace down the leak. It looks like it's coming out of the radiator cap. I don't really see anything wrong with the cap but I don't have a good way to test it. A new one, OEM, is about $35! FleaBay has used ones for $5 but that's someone else's problems. Any suggestions on how it can reseat the cap without getting a new one?
 
#23 ·
The no-cost method is to place the cap on a workbench or whatever with the metal part down and press down on the rubber seal assembly to make certain that there is some "give,' in other words it should feel like there is a tension spring and that it is working. Also check to make certain that the rubber seal itself doesn't have any cracks or breaks and that both it and the radiator sealing flange where the cap gasket seals are clean.
 
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