coolant leak, right side

Joined
Jun 12, 2008
Messages
239
Age
60
Location
Minnesota
Bike
2005 Honda ST1300
Hey All,

I just fired up the 2004 ST1300 for the first time after a 4 month winter nap and had a cloud of steam boiling off the right hand side.
I'm assuming a coolant leak somewhere.

Hope to get the bodywork off and check things out this weekend. I bought the bike with 75,000 miles in August of 2017 and have put on another 8,000 the last two years. Didn't notice any leaks the last oil change.

Could someone with experience take the time to point out likely areas to search?

Appreciated,
Kent Larson from Minnesota
 
I would check out the large hose that connects to the top of the radiator on the right-hand side. Maybe the rubber hose has deteriorated/split or the clamps need tightening. Since you see a cloud of steam, it should be very easy to find the culprit once the fairing is off. Best of luck...
 
Hi Kent:

Here are a couple of pictures showing a dis-assembled ST 1300 that illustrate the location of all the hoses and clamps on the right-hand side of the motorcycle. As you can see, there are a whole bunch of hose clamps on the right side, as well as the thermostat up at the top of the engine.

If it is a hose leak, my guess would be one end or another of the big hose that connects the radiator to the water pump. The problem could also be a loose cap on the radiator, or, a loose clamp on the little hose leading from just under the radiator cap to the overflow tank on the left side.

Chances are that you will need to take the big right side Tupperware panel off to fully inspect and also to get adequate access to the hose clamps.

See also this article for background information about two weep holes on the right side of the engine: ST1300 - Water Pump Weep Holes Although it is unlikely that the steam is coming from either of the weep holes, chances are that once you get in there and start investigation, you might discover evidence of past or present coolant leaks from one of those holes, and that will then influence how much additional investigation you need to make before determining what needs to be repaired or replaced.

Michael

237707
 
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It's a known problem when the bikes been stood over winter the hose clamps around the thermostat housing may need tightening or it could be the mechanical seal, mine was the same, check coolent level, if it's the mechanical seal it may fix itself when ridden. You could always change the clamps for the constant presure spring ones. There are two places to look one is the weep hole by the water pump and the other it the rectangular hole just below it237708

If it's the rectangular hole this is a vent from the valley at the top of the engine and would suggest it's a leak from the top hoses, you will need to take the rad off to get to them
 
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Wow. It's always an understatement about how great this site is with all the ready knowledge and help at hand.
Thanks guys. I'll post back what I found when I get the Tupperware off tomorrow. May as well give her fresh oil for spring while I'm in there.

Later,
Kent Larson from Minnesota
 
Hey All,

I just fired up the 2004 ST1300 for the first time after a 4 month winter nap and had a cloud of steam boiling off the right hand side.
I'm assuming a coolant leak somewhere.

Hope to get the bodywork off and check things out this weekend. I bought the bike with 75,000 miles in August of 2017 and have put on another 8,000 the last two years. Didn't notice any leaks the last oil change.

Could someone with experience take the time to point out likely areas to search?

Appreciated,
Kent Larson from Minnesota
I will be starting my 04 on April 20th after over five months. Keeping fingers X'd. The Chicago winter was brutal with record cold this year. No leaks on the ground. Hate leaks and taking the plastic off. :(
 
Hi Kent,

This is quite common. If you want to really fix it, pick up some Aviation Formagasket. Here is a link to it in Amazon but I have have found it at local auto parts stores. Both my 1300s have been treated and never leaked again. Oh I also replaced all my clamps with the Breeze Clamps that have the springs (looked like stacked washers)

Here is a link to the clamps and sizes. I think those are the sizes I ordered.


Take a look at this article.

 
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I also replaced all my clamps with the Breeze Clamps that have the springs (looked like stacked washers)
But, don't use Breeze clamps (constant tension clamps) on the inlet and outlet to the ST 1100 radiator. If they are torqued to the specified torque when installed on either of the two radiator fittings, they will crush the very thin radiator fittings. I learned this the hard way.

The Breeze clamps are excellent for use on all cast (solid metal) fittings.

Michael
 
I had the same issue this spring. I never saw any coolant on the floor, but did smell some last summer while sitting at a stop light and then when I parked the bike in my garage. I removed all the fairings ( a real pain in the butt to me ) and used a flashlight to try and find the coolant drip. I saw some coolant on the end of one of the rad hoses that attached to the thermostat housing. I decided to buy two rad hoses and then get into the system and see what else it needed. Once you remove the radiator, you have access to most of the hose clamps. You should tighten all the ones you can get to , but don't go too tight or you can destroy the hoses. I reused most of the clamps but I replaced a couple that didn't look too good. I stayed with the regular hose clamps, they seem to work ok.
I also replaced the weak part of the coolant system called the fuel tube I think . It's a plastic T that will eventually get brittle and crack. (helpful information found on this site) It's on the right side of the bike about 6 inches from the radiator. I found a brass T coupling and screwed in barbed fittings. Two are 1/4" and one is 5/16". (i can show you a picture if you want) This shouldn't be a factor ever again I'm hoping.
Good luck finding and preventing your coolant leaks.
 
If you do use Breeze clamps, pay attention to how you orient the screw on the clamp. Since the 'stacked washer' part of the clamp is larger than the OEM clamps, it is easy to install them in such a way that assembly of other pieces will hit the clamps (think faring, but not limited to that). IIRC, the spec'ed torque is 90 in lb, though someone else posted 45 here and I tightened mine to the latter number and have had no leaks after a couple of years.
 
...I also replaced the weak part of the coolant system called the fuel tube I think . It's a plastic T that will eventually get brittle and crack ... It's on the right side of the bike about 6 inches from the radiator.
Here's a picture of that plastic T fitting that Kevcules refers to in his post above. It can be difficult to find this fitting because it is usually tucked away directly in front of the right front cylinder and obscured by the radiator in front of it and the engine block behind it. I have no idea what purpose it serves - obviously, to direct coolant somewhere, but where and why I don't know.

The picture was taken from right about where the ignition switch is, looking downwards at the engine - you can see the big hose that connects to the radiator in the background at the far left edge of the picture, just below the middle of the picture.

Michael

Plastic T Fitting
237750
 
Here are a few more pictures of the plastic T to help you find it. I also added a few pics of my brass fitting replacement. Not necessary to do, but I like to try to take care of any issues when Im in the area. Taking off the fairings isn't my favorite thing to do :)
 

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My issue was a leaking tube at the back of the thermostat. It is snitched up for now and didn't give me any more smoke at startup yesterday or today. When I have some time I'll go back in and do some of the other mods to avoid future problems.

Thanks for all the help with links and great information. Interesting that this sight is just right there with helpful replies. My question would have only generated a few, justified, responses of...
"The information is all there just go look it up, you lazy twit."
...from other sites I've participated on in the past. Here, it was all just quick useful information.

Thanks for assisting this lazy twit.

Later,
Kent
 
Here are a few more pictures of the plastic T to help you find it. I also added a few pics of my brass fitting replacement. Not necessary to do, but I like to try to take care of any issues when Im in the area. Taking off the fairings isn't my favorite thing to do :)
Yes, Kevcules. Where did you get or how did you make the brass fitting? I'm thinking of replacing my plastic 3 way sometime soon. Both "Red Dirt Cowboy" and I are interested.

Thanks,
Kent
 
Hey guys.....I went to a place that sells brass fittings only......I can get the name of this place if you would like.

The clerk measured my plastic "T" and gave me the standard brass "T" fitting ,with 3 brass barbed end matching sizes. I think they were 2 @ 1/4" and 1 @ 5/16". The barbed ends are so long , I decided to double clamp them once the hose was on. Barbed fittings hold so well, I probably didn't have to clamp them at all. Make sure you trim the hose lengths properly when you install the larger brass assembly because once you slide the hose on, good luck getting it off.
Larry (igofar) had mentioned this a few times in past threads that these plastic Tees are susceptible to breaking so it was good to have a spare at all times. I decided to take care of the possible failure.
I couldn't find a 1 piece aluminum or brass piece to replace the plastic one for the life of me ,so I decided to use brass fittings. No issues at all....
 

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Hey guys.....I went to a place that sells brass fittings only......I can get the name of this place if you would like.

The clerk measured my plastic "T" and gave me the standard brass "T" fitting ,with 3 brass barbed end matching sizes. I think they were 2 @ 1/4" and 1 @ 5/16". The barbed ends are so long , I decided to double clamp them once the hose was on. Barbed fittings hold so well, I probably didn't have to clamp them at all. Make sure you trim the hose lengths properly when you install the larger brass assembly because once you slide the hose on, good luck getting it off.
Larry (igofar) had mentioned this a few times in past threads that these plastic Tees are susceptible to breaking so it was good to have a spare at all times. I decided to take care of the possible failure.
I couldn't find a 1 piece aluminum or brass piece to replace the plastic one for the life of me ,so I decided to use brass fittings. No issues at all....
Names Please....for the love of GOD Names :please1:
Nice find, nice fix! Thanks for sharing.
 
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