What else but another coolant leak

dduelin

Tune my heart to sing Thy grace
Site Supporter
Joined
Feb 11, 2006
Messages
9,640
Location
Jacksonville
Bike
GL1800 R1200RT NC700
2024 Miles
006739
STOC #
6651
I was replying to no one in particular other than Mark and his reply to me about how his bike continued to leak each season after tightening the clamps and mine does not. He mentioned that a dealer warranty tightened the clamps the first time.....presumably not in Mark's presence. In that case there would be no way to know how much force was applied.

I still think extended lay ups in cold temps also has something to do with it. My boats had many worm type screw clamps securing hoses on fresh water and sanitation systems, open system sea water engine cooling systems and closed system heat exchanger systems. The air temp in the boat was almost always over 40F and I ran it on average 3 or 4 times a month. I never had a leaking problem with those hoses. To your point made earlier I tended to use better quality non perforated wider band clamps and these type always on critical below waterline applications. The one clamp I did reply on my '05 I used one like this made by Awab. It costs a good deal more than the OEM ST clamps.
 
Joined
Jul 28, 2007
Messages
3,120
Location
finger lakes ny
Bike
1999 ST1100
STOC #
7959
Joined
Jan 29, 2017
Messages
18
Location
SC
Classic ST1300 weep, seep, leak from a thermostat housing O ring or a hose or hoses that attach to it. The coolant runs downhill from between the Vee of the cylinder banks in a provided channel between the front cover and the engine block and exits out of the square hole on the lower right side. That is a drain channel coming down from above. Some coolant will run down the front of the engine if the leak gets worse. What we are talking about are minor leaks but they make a mess when mixed with road grime. Easy problem to deal with. It's not the water pump....if that leaks or weeps it comes out of the drain hose seen in pics #1 and #2.

Pull the plastics off again. Remove the radiator. Remove the frame cross member just above the engine that connects the frame across there. Two bolts secure the cross member, one on either side. Now you can see and work on the thermostat housing that resides there. Replacing the thermostat housing O ring is a given, Honda P/N 91361-MCS-A10. Snug the clamps on the hoses that attach to the thermostat housing and the two on the cylinder heads that connect the cylinder head join hoses. You will need a 6 mm socket and some extensions for a 1/4" rachet to get at the clamps. If you have a long flexible nut driver that will work too.

Some folks replace all the OEM clamps with constant pressure clamps and some just snug the clamps up. I dealt with weeps by simply snugging the clamps at 65,000 miles and of course the leaking O ring. I replaced all the hoses in the vee at 106,000 miles and sure enough at 165,000 miles I had another recurrence of this messy but minor problem. I did this just two weeks ago. I did replace one clamp this time.

PM me your email and I'll send you a step by step tutorial with pics detailing radiator removal and accessing the thermostat the easy way. The service manual tells us to remove the throttle bodies which is much more complicated.
Any chance I could get in on this info, too? info@bdscycles.com
 
Joined
Jan 8, 2011
Messages
7,062
Location
Arizona
Bike
2007 Honda ST1300A
I'll throw this little tidbit of info out here....one of the spring clamps (larger one) that secure the fuel line hose at the rear of the upper fuel tank, is the exact same size as the (4) known hoses that leak on the water pipes.
If you purchase a pair of remote spring clamp pliers, and 4 of these clamps, you may never have another leak again. These are the same clamps on all Honda cars and SUV's....Element, CRV, etc.
 

Mellow

Joe
Admin
Joined
Dec 1, 2004
Messages
18,826
Age
59
Bike
'21 BMW R1250RT
2024 Miles
000540
I'll throw this little tidbit of info out here....one of the spring clamps (larger one) that secure the fuel line hose at the rear of the upper fuel tank, is the exact same size as the (4) known hoses that leak on the water pipes.
If you purchase a pair of remote spring clamp pliers, and 4 of these clamps, you may never have another leak again. These are the same clamps on all Honda cars and SUV's....Element, CRV, etc.
I'm not sure that is correct for all years, in 2008 the tank changed slightly and a different sized hose is used to connect the upper/lower tanks.

https://www.st-owners.com/forums/showthread.php?115913-ST1300-Fuel-Tank-Hose-Leak-(Near-Miss)&p=1465434&viewfull=1#post1465434

 
Joined
Jan 8, 2011
Messages
7,062
Location
Arizona
Bike
2007 Honda ST1300A
OP
OP
Joined
Aug 30, 2008
Messages
98
Location
Jenks, OK
Bike
2017 BMW R1200GSA
Update: Lots of good discussion going on. I'm going to chalk up my issue to loose hose clamps (certainly) and some weeping from the thermostat housing (suspected). I've taken the bike out several times and also let it sit for several days and have not seen any leaks since I tightened everything up. I still have the plastic off. Someone commented about checking for leaks when the bike is cold. I agree. I stated in my initial post that I wouldn't see any leaking until after several days of letting the bike sit. Also, my detached garage is not insulated so if it's 20 degrees outside, then it's 20 degrees inside my garage. (I have a thermometer on the wall.) Here's a link to the Mityvac 4510...

http://mityvac.com/pages/products_cse.asp#MV4510
 
Joined
Jan 8, 2011
Messages
7,062
Location
Arizona
Bike
2007 Honda ST1300A
While checking for leaks, you'll also want to check the 3 way plastic joint behind the radiator cap...just follow the hose back to it. Be very careful when tightening the hose clamps, as the plastic joint breaks and will leave you stranded.
It has two different dia. as well. I found ordering a spring clamp to match the small one by the cap, and then going to a parts store and purchasing a smaller one to fit the other lines protects the joint from breaking, and stops this area from leaking as well.
 
Joined
Oct 6, 2007
Messages
523
Location
Kenly NC
Bike
07 ST1300A(P)
STOC #
7649
While checking for leaks, you'll also want to check the 3 way plastic joint behind the radiator cap...just follow the hose back to it. Be very careful when tightening the hose clamps, as the plastic joint breaks and will leave you stranded.
It has two different dia. as well. I found ordering a spring clamp to match the small one by the cap, and then going to a parts store and purchasing a smaller one to fit the other lines protects the joint from breaking, and stops this area from leaking as well.
+1 mine broke the other day, typical of plastic parts bathed in coolant for years. I manufactured one out of steel brake lines, brazed into a T. So far it's the only part that's not leaking..... I wonder if there is a market for these and the little 4 way at the throttle bodies?...... I need to call my buddy Wun Hung Lo in china.
 

NewtonNole

Site Supporter
Joined
Nov 14, 2018
Messages
88
Age
49
Location
Bristol Florida
Classic ST1300 weep, seep, leak from a thermostat housing O ring or a hose or hoses that attach to it. The coolant runs downhill from between the Vee of the cylinder banks in a provided channel between the front cover and the engine block and exits out of the square hole on the lower right side. That is a drain channel coming down from above. Some coolant will run down the front of the engine if the leak gets worse. What we are talking about are minor leaks but they make a mess when mixed with road grime. Easy problem to deal with. It's not the water pump....if that leaks or weeps it comes out of the drain hose seen in pics #1 and #2.

Pull the plastics off again. Remove the radiator. Remove the frame cross member just above the engine that connects the frame across there. Two bolts secure the cross member, one on either side. Now you can see and work on the thermostat housing that resides there. Replacing the thermostat housing O ring is a given, Honda P/N 91361-MCS-A10. Snug the clamps on the hoses that attach to the thermostat housing and the two on the cylinder heads that connect the cylinder head join hoses. You will need a 6 mm socket and some extensions for a 1/4" rachet to get at the clamps. If you have a long flexible nut driver that will work too.

Some folks replace all the OEM clamps with constant pressure clamps and some just snug the clamps up. I dealt with weeps by simply snugging the clamps at 65,000 miles and of course the leaking O ring. I replaced all the hoses in the vee at 106,000 miles and sure enough at 165,000 miles I had another recurrence of this messy but minor problem. I did this just two weeks ago. I did replace one clamp this time.

PM me your email and I'll send you a step by step tutorial with pics detailing radiator removal and accessing the thermostat the easy way. The service manual tells us to remove the throttle bodies which is much more complicated.
Brand new ST owner. I have ran into this problem, and I was doing a search. I apologize for a dated reply, but it's my first post and couldn't message.
 
Joined
May 8, 2018
Messages
1,944
Location
illinois
Bike
2000 ST1100
Don't know if its been already said but your rubber hoses will contract some in the cold weather while it sitting. Mine does this too in the garage but the couple of tablespoons it loses I don't worry about. In the spring summer time doen't leak a drop.
 

ibike2havefun

Still above the sod
Site Supporter
Joined
Jan 8, 2015
Messages
2,762
Location
Rockville, MD, USA
Bike
Bikeless (9/29/2019)
STOC #
8824
I'll throw this little tidbit of info out here....one of the spring clamps (larger one) that secure the fuel line hose at the rear of the upper fuel tank, is the exact same size as the (4) known hoses that leak on the water pipes.
If you purchase a pair of remote spring clamp pliers, and 4 of these clamps, you may never have another leak again. These are the same clamps on all Honda cars and SUV's....Element, CRV, etc.
Just checking to make sure I have the right info. This is the part number for the radiator hoses:

CLAMP, HOSE (30-37MM)

19516-GAG-003


and you are saying I can replace it with this one, yes?

CLIP, HEATER HOSE (30MM)

90661-SL0-A01


Or is there another part number I should look for? Given that this may also be a Honda auto part, is there a part number equivalence cross reference anywhere? My Honda auto dealer is just a half mile from the office; Mother Honda's nearest red wing shop is 35 miles away. Partzilla, Service Honda, etc. may be alternative sources.

If it doesn't have to be a genuine Honda part (and why should it be?) would "any old 30 mm spring type hose clip" do the job? Presumably even Advance Auto Parts would carry such an item.

I ask because my ST left a small blue puddle during the seven weeks I left it unattended in the un-heated storage unit. Never leaked when I used a climate-controlled storage facility but that's in the past. So I know I have some work to do, come spring.

Thanks.
 
Top Bottom