Slowly Losing Coolant in Overflow

[roadrunnazpres]

I have a 04 fz6 40k on clock, notice coolant levels drop after riding. At first I thought it was just the overflow tank coolant levels fluctuating due to usage warming up and cooling down engine. Until the coolant levels remained low, causing me to have to keep refilling it. I never let it drop below min mark before refilling it to max. I would say I have to refill every 2 full tanks of gas depending on how hard I'm riding it, so I'm slowly losing coolant (6oz of coolant if I had to guess). I did a coolant flush using engine ice about a month ago and removed radiator cap with engine running to remove any air bubbles and also to make sure it was not boiling over which is a sign of blown head gasket. Also, far as white smoke another sign of head gasket leak, there's is no clearly noticeable or obvious white smoke but it is starting to get cold out so slightly harder to indicate. Bike running strong, radiator cap looks healthy but still considering changing due to bikes age, no coolant drips on ground, although I could be possibly over looking a small leak around overflow tank due to tight space. just don't know where my coolant is going, any suggestions?
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[Marcelor73]

Since there's no clear leak, my first suggestion would be to pressure test the system to try to find the leak. You can add a UV dye then look for it with a UV light.

It has to be going somewhere. Have you had someone ride behind you and specifically look for smoke?

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[bigborer]

How's the engine oil?

 

[Marcelor73]

How's the engine oil?

I thought about that too, but he's losing a lot. If he had milkshake oil going on he'd know by now.

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[TownsendsFJR1300]

Also, check ALL your coolant hose clamps. They do loosen over time.

A little coolant from a leaking hose (or water pump), would evaporate (with the engine heat) and be very difficult to find.

Head gasket failures are pretty rare for this engine but as noted, check the engine oil for any coolant dilution...

 

[Gary in NJ]

A cap that is out of spec will also allow a mysterious loss of coolant.

 

[roadrunnazpres]

How's the engine oil?

still looks goods not milky or nothing, will keep my eye on overtime since oil still new changed 400 miles ago.

 

[roadrunnazpres]

Yea i'll try the UV dye method since it easy, and get someone to ride behind and see if they notice, thanks

 

[roadrunnazpres]

A cap that is out of spec will also allow a mysterious loss of coolant.

Yea I'm just order the cap, hopefully easy fix when come.

 

[Motogiro]

I recently thought I was loosing coolant. I was also worried about a gasket leak because there was no apparent leak or sign of coolant anywhere outside the engine. I had to refill it twice using the overflow res. The last refill I checked the radiator cap , Wiped and inspected washer and mating surface. Ran the bike on an all day trip last month and no coolant loss. Sometimes you need to tilt the bike side to side to make sure any air is dispersed after servicing the system.

Standard coolant for our bikes is generally a 50:50 mix of the coolant and water. Most coolants are premixed.