coolant leak at rear of engine

Catmandu2

Catmandu2

Joined
Sep 22, 2015
Messages
1,297
Location
Wasaga Beach, Ont. Canada
Bike
'04 ST1300 Blue STar
Lately,, Blue STar has been dripping coolant at the rear of the engine,,, where it is really hard to see the source. The drips are forming off the oil cooler,,, which has 2 hoses coming down from the top of the engine valley. It is common to see cold weather seeps from the valley at the front of the engine. There is even a designed path for frontal coolant to drain through. There is nothing like that at the back of the motor, that I know of. I thought all of the hose clamps that usually need re-tightening are located at, or forward of the front throttle bodies. What would drips down the rear of the engine likely indicate ?? Here is a file photo of an engine showing where the coolant lines descend to the oil cooler. Also,,, a partzilla hose diagram. I am hoping to avoid removing the throttle bodies, in order to fix this. Its been about 3-4 years since I last retightened clamps,,, with good results till now. Never hurts to ask about other's experiences,,, thx,,, CAt'

240416201_4463540937046812_2485302031921374378_n.jpgMjA0NTk1Ng-1a042c22.png
 
I would think that your hoses need replacement at the age of that bike. I have replaced all of mine on my 07 ST.
 
Mellow,,, sorry, but I should have placed this thread in st1300 Leaks.

Also,, just brain storming on why it might be dripping off the left side rear of the engine,, (especially when the bike is placed on the side stand) but not so much off the front drip channel (square hole),, even if on the center stand. Perhaps the front drip channel is clogged up. Likely worth checking,, before digging deeper,,, CAt'
 
on top of the oil cooler there are 2 hoses containing cooling fluid
E-13 goes to E-20, see appendix
 

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mvdv said:
on top of the oil cooler there are 2 hoses containing cooling fluid
E-13 goes to E-20, see appendix
Click to expand...
Yes,,, thanks,,, those were the first item's that I checked,,, as they can be easily checked and re-tightened. They are tight,, and the coolant seems to be coming from higher up,,, and running down the back of the motor. Since the weather has warmed up,,, the drips have stopped. So I have been busy riding,, for now,,, cheers,,, CAt'
 
I have had to replace those lines due to chafing through. The clamps can be loosened and the hose pulled relatively easily. Tie a string to one end before pulling so you can draw the new hose down. Put a little anti seize on the inside of the new hose and it will slip right over the nipple on the oil cooler. DO JOT REMOVE THE OIL COOLER, the oring is no longer available.
 
Check your coolant overflow tank.
It’s common the find melted holes, or cracks on the mounting point and rear of the bottle.
These leaks follow the hoses down and end up in the area where you see your leaks.
Clean everywhere then spray some white foot powder all over, it will show you where your leaks are coming from quickly.
 
There is an oil cooler o-ring that works on Amazon:
(5x58x64 o-ring actual) fits the groove like it was made for it.
A 3/8 breaker bar with 1/2 adapter (30mm socket) for the oil cooler nut.
Pulling the cooler down gives full, easy access to the hose clamps.
Splicing the old and new lines together with 1/4" hose fittings (white, photo) and wrapping with tape pulls the new lines down to the cooler.
I replaced the water pump and all the water hoses. 50 miles now and tight as a drum.
30mm.jpeg
 
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