Coolant overflow issues
- Nybz
- Posts: 16
- Joined: Mon Jan 02, 2017 9:27 pm
- Location: Victoria BC Canada
- Motorcycle: 1982 GL1100
Honda 1980 CM400T
Coolant overflow issues
Hey everyone,
Just got my first goldwing this fall. Pretty new to motorbike mechanics but been enjoying learning.
Been having an issue with coolant leaking from the over flow tube on the ground.
It starts to warm up (not even past the blue cold mark) and then it starts to leak.
Changed the rad cap (old one was 16psi, new one 13psi)
I flushed out the coolant recently, burped it, but still leaking today.
The head gaskets were changed out recently so I am hoping I don't have to go in there again.
But it seems weird that it is coming out of the overflow tube when the reservior tank is not even at the full mark.
It doesn't seem to be sucking coolant back into the rad when it cools down.....
Maybe there is a hose missing in the reservoir? but I don't see how it would suck any thing back in because the inlet hole is at the top of the reservior with no tube going down into the reservoir
Also the leaking stops when I take off the reservior cap.
Any ideas?
Thanks for the help.
Just got my first goldwing this fall. Pretty new to motorbike mechanics but been enjoying learning.
Been having an issue with coolant leaking from the over flow tube on the ground.
It starts to warm up (not even past the blue cold mark) and then it starts to leak.
Changed the rad cap (old one was 16psi, new one 13psi)
I flushed out the coolant recently, burped it, but still leaking today.
The head gaskets were changed out recently so I am hoping I don't have to go in there again.
But it seems weird that it is coming out of the overflow tube when the reservior tank is not even at the full mark.
It doesn't seem to be sucking coolant back into the rad when it cools down.....
Maybe there is a hose missing in the reservoir? but I don't see how it would suck any thing back in because the inlet hole is at the top of the reservior with no tube going down into the reservoir
Also the leaking stops when I take off the reservior cap.
Any ideas?
Thanks for the help.
- WingAdmin
- Site Admin
- Posts: 23411
- Joined: Fri Oct 03, 2008 4:16 pm
- Location: Strongsville, OH
- Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (sold)
1998 XV250 Virago (sold)
2012 Suzuki Burgman 400 (wife's!)
2007 Aspen Sentry Trailer - Contact:
Re: Coolant overflow issues
Where exactly is the leaking occurring?
There can be cracks in the tube that runs from the radiator neck to the overflow reservoir, or sometimes in the reservoir itself where the tube connects to it. This can cause a leak as soon as the bike warms up. When it cools off, instead of sucking coolant up from the reservoir, it sucks air in through the crack, and you end up with air in the cooling system.
Check to see if you can identify where exactly the leak is occurring.
There can be cracks in the tube that runs from the radiator neck to the overflow reservoir, or sometimes in the reservoir itself where the tube connects to it. This can cause a leak as soon as the bike warms up. When it cools off, instead of sucking coolant up from the reservoir, it sucks air in through the crack, and you end up with air in the cooling system.
Check to see if you can identify where exactly the leak is occurring.
- Nybz
- Posts: 16
- Joined: Mon Jan 02, 2017 9:27 pm
- Location: Victoria BC Canada
- Motorcycle: 1982 GL1100
Honda 1980 CM400T
Re: Coolant overflow issues
The leak is coming out of the end of the reservior over flow tube, that leads to the ground
There is a rubber piece on the reservior that connects to the over flow tube that is cracked that might be sucking in air?...
Also left wondering how the coolant gets back into the rad, if the only input from the rad into to reservior is at the top of the reservior above the "full mark", with no tube going down into the reservior to suck it up.
Am I missing something?
There is a rubber piece on the reservior that connects to the over flow tube that is cracked that might be sucking in air?...
Also left wondering how the coolant gets back into the rad, if the only input from the rad into to reservior is at the top of the reservior above the "full mark", with no tube going down into the reservior to suck it up.
Am I missing something?
- Nybz
- Posts: 16
- Joined: Mon Jan 02, 2017 9:27 pm
- Location: Victoria BC Canada
- Motorcycle: 1982 GL1100
Honda 1980 CM400T
Re: Coolant overflow issues
Since I have been messing with that cracked rubber piece on the reservior connecting the overflow tube, making it worse, the leak is now coming from the cracked bit and not out of the bottom of the overflow tube
- Nybz
- Posts: 16
- Joined: Mon Jan 02, 2017 9:27 pm
- Location: Victoria BC Canada
- Motorcycle: 1982 GL1100
Honda 1980 CM400T
Re: Coolant overflow issues
Just had a thought that maybe the two tubes (the one from the rad and the overflow tube) got switched around at some point?
The over flow tube goes down into the reservoir, where as the tube from the rad is only at the top. Makes sense to me that perhaps they got mixed up...?
Any idea where I can get a new rubber piece on the reservior that is cracked/shot?
Thanks for the help.
The over flow tube goes down into the reservoir, where as the tube from the rad is only at the top. Makes sense to me that perhaps they got mixed up...?
Any idea where I can get a new rubber piece on the reservior that is cracked/shot?
Thanks for the help.
- Nybz
- Posts: 16
- Joined: Mon Jan 02, 2017 9:27 pm
- Location: Victoria BC Canada
- Motorcycle: 1982 GL1100
Honda 1980 CM400T
Re: Coolant overflow issues
The black tube is coming from the rad, and the clear tube (with the cracked rubber) goes to the ground.... are they hooked up wrong?
- WingAdmin
- Site Admin
- Posts: 23411
- Joined: Fri Oct 03, 2008 4:16 pm
- Location: Strongsville, OH
- Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (sold)
1998 XV250 Virago (sold)
2012 Suzuki Burgman 400 (wife's!)
2007 Aspen Sentry Trailer - Contact:
Re: Coolant overflow issues
You got it, someone has hooked them up backwards. The black hose from the radiator hooks up to the siphon, and the clear(ish) tube to ground hooks up at the top overflow nipple:Nybz wrote:The black tube is coming from the rad, and the clear tube (with the cracked rubber) goes to the ground.... are they hooked up wrong?

- Nybz
- Posts: 16
- Joined: Mon Jan 02, 2017 9:27 pm
- Location: Victoria BC Canada
- Motorcycle: 1982 GL1100
Honda 1980 CM400T
Re: Coolant overflow issues
Explains why coolant is being pushed out when coolant is being added to the reservior.
Thanks wing admin for the help!
Now, gotta find a new/used/fixed broken rubber piece for the siphon.
Thanks wing admin for the help!
Now, gotta find a new/used/fixed broken rubber piece for the siphon.
- spiralout
- Posts: 1202
- Joined: Sun Feb 17, 2013 6:41 pm
- Location: Alabama
- Motorcycle: 1975 GL1000 (gone)
1980 GL1100I (with '77 1000 engine)
1996 GL1500 SE
Re: Coolant overflow issues
http://shop.westernhonda.com/fiche_sect ... veh=132951Nybz wrote: Now, gotta find a new/used/fixed broken rubber piece for the siphon.
#2 on the diagram?
- Nybz
- Posts: 16
- Joined: Mon Jan 02, 2017 9:27 pm
- Location: Victoria BC Canada
- Motorcycle: 1982 GL1100
Honda 1980 CM400T
Re: Coolant overflow issues
Ordered! along with a few other little bits and pieces.
Thanks for the help
Thanks for the help
- NevsMate
- Posts: 15
- Joined: Thu Apr 19, 2018 5:59 am
- Location: N Wales, UK
- Motorcycle: 1981 GL1100 dressed, unsure if true Interstate (but, investigating)
Re: Coolant overflow issues
Have been monitoring my coolant levels for a couple of weeks, sometimes it's ok and others it drained away into another dimension!
But, hey after your similar problem and easy fix found similar on the top of that syphon the rubber was perishing under the metal retaining clip! Something that simple.
Ain't these forums great.
thanks guys..
But, hey after your similar problem and easy fix found similar on the top of that syphon the rubber was perishing under the metal retaining clip! Something that simple.
Ain't these forums great.
thanks guys..

Plumber, Butcher, UK Armed Forces, Mountain Rescue Volunteer, Distribution Manager, I.T. Consultant