Leaking Coolant

Joined
Jun 12, 2015
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446
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62
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Brookfield,WI
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2015 K1600 GTL E
2024 Miles
000220
So I did tire change. Jacked up front an everything. No worries. Started it up which I do in the usual place in the driveway after backing out of the garage . Leaking from front lower cowl. Went short ride. Nothing leaking when parked. Went for longer ride next day. Nothing. Let her sit for 6 days. Same thing. Nothing in garage. Only at start up. It’s not a lot but still there. Any answers. Just over 47k miles. Have not done any maintenance on cooling system.
 

dduelin

Tune my heart to sing Thy grace
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Jacksonville
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GL1800 R1200RT NC700
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6651
Coolant leaks are very common on the ST1300 but it is easily set to right.

You will get replies ranging from snugging up the original clamps to replacing all of them from stem to stern. During the valve check services which I did about every 20-24,000 miles to 180,000 miles I removed the radiator and snugged up the OEM clamps and replaced the O-ring in the thermostat housing. This is what I did and it took care of the coolant leaks on my ST1300.

Leaks are so common that we have a sub forum for them: https://www.st-owners.com/forums/forums/st1300-leaks.457/
 
Joined
May 8, 2018
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1,952
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illinois
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2000 ST1100
So I did tire change. Jacked up front an everything. No worries. Started it up which I do in the usual place in the driveway after backing out of the garage . Leaking from front lower cowl. Went short ride. Nothing leaking when parked. Went for longer ride next day. Nothing. Let her sit for 6 days. Same thing. Nothing in garage. Only at start up. It’s not a lot but still there. Any answers. Just over 47k miles. Have not done any maintenance on cooling system.
Might be your hose clamps. You stated that when you ride and park it you get no leaks. I suspect the hoses have expanded so you won't get any leaks. After it cools down the hoses contract. When you start it cold the water pump is pushing coolant through those contracted hoses thus the leakage.
 

Igofar

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Lots of information on coolant leaks on the forum, grab some coffee and start reading.
I will add a couple comments however, DON'T just snug down the clamps, because often the coolant gets between the pipe and the hose and will start eating away at the metal and corrode and causing pitting. If this is the case, tightening the clamps may just make the leak worse.
Also, a lot of folks over look the water pump cover o-ring when having leak issues. Since the drain hole from the the upper end drains through this area, and runs down along the shelf, down to exit the square hole, it could be an upper leak, or a o-ring leak. Check both.
Lastly, DON'T over tighten the radiator hoses on the radiator itself, or you'll crush/distort the pipes. If you do this, it will really leak badly.
If you find the pipes egg shaped, or damaged, get yourself two ball peen hammers and use the big big one to true up the hole, while using a smaller one to tap the face of the larger one.
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CYYJ

Michael
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Here's a post that will give you the information you need to determine if the leak is coming from the water pump seals (not good) or from the V in the middle of the engine (also not very good, but somewhat less critical and generally easier to fix):

ST1300 - Water Pump Weep Holes

Be aware that if you wash your motorcycle and you do a really good job of washing it (spraying water from the garden hose everywhere, especially into the sides of the engine), some of that wash water will accumulate in the V between the cylinder banks and just sit there. Later, if you start the bike up and move it around, that water will then run out of the square hole. That's normal, nothing to worry about - in fact, that's why the square hole is there, to let liquid trapped in the V of the engine drain out. From what you wrote in your first post, I think that is what is happening to you.

If you have small leaks (insignificant leaks) from the various hoses in the V of the engine, the leaking coolant residue will get washed out with the water you used to clean the moto. This might cause you some worry because it will look like coolant. What you need to do is determine what the rate of coolant loss is.

Keep track of the coolant level in the reservoir bottle on the left side of the engine, down by your left ankle. If it only goes down a little bit over the course of a riding season (for example, you lose an inch of coolant over 6 months), it might not be worth your while to start tearing the bike apart to find the leak. On the other hand, if you are losing an inch of coolant once a month, it might be appropriate to find and correct the problem.

l see from your profile that your bike is a 2007. That means that the coolant hoses are now about 14 years old. If you plan to keep the motorcycle, it would be prudent to plan to replace the hoses & clamps within the V area next winter. I understand that Wisconsin winters are long enough to let you get the job done at a leisurely pace... :)

Michael
 

CYYJ

Michael
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DON'T over tighten the radiator hoses on the radiator itself, or you'll crush/distort the pipes. If you do this, it will really leak badly.
That is really good advice, do not disregard it. The correct torque value for the hose clamps that go into each end of the radiator is about one-one-hundredth of a foot pound. If you apply too much torque, you will crush those little pipes coming out of the radiator in the blink of an eye, and you won't know you are crushing them, because they are covered up with the coolant hose. Don't ask me how I know this....

Michael
 
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