Coolant loss

Some of you guys who are also on Facebook will know that I have just ridden across the Nullarbor to WA. For most of the trip I had no real issues but on the second last day I found coolant coming out of the overflow when I stopped for fuel.

Hoping it was a failing radiator cap I got a new one in Albany. Today however I found the radiator slightly down on coolant and the expansion bottle fairly full but not overflowing yet.
Topped the radiator up and with the cap on ran the bike up until the fan was cutting in and out. While this was happening I noticed a few bubbles in the expansion tank . Then left the bike for an hour and checked again. The coolant in radiator had dropped again. So thinking maybe air stuck in the system I'd run it with the cap off. With the coolant slightly down from the cap, start the bike and within seconds its about to overflow. Turn the motor off and take some coolant out, then try again, same thing.
Is this air trapped in the system or combustion gases forcing the coolant to overflow.
Any ideas?

Hey madmax, did a quick google search and found a thread on the uk site which may be relevant, here's the link: http://www.banditforum.co.uk/forum/index.php?action=printpage;topic=57868.0  And a couple of hopefully relevant quotes:

"Post by: Wobble on January 16, 2013, 01:45:16 AM

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This happens the world over for bandits. Follow the coolant pipes and you will see what a stupid system it is. Just before the bottom of the expansion tank is a Y piece which bypasses the tank and joins with the overflow pipe near the tank cap. Overflow coolant from the engine takes the path of least resistance, which when very hot seems NOT to be through the tank! Also if the tank cap/plug is not in just right it can block the tanks overflow outlet hole completely. I find having the cold level just below the low level mark helps as well.

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Title: Re: Venting Coolant on a 1250
Post by: 1250Andy on January 19, 2013, 07:25:33 AM

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What Wobble said is spot on..  :icon_thumright:

I had problems with mine until I had a look at the cooling system and in the end I took the rear panel off to get better access and changed the Y pipe that's just before the expansion tank for a straight through connector and did away with the bypass pipe. 

I've had no problems since."


 This sounds like a common problem, maybe worth a look. Good luck!

What wobble says is not relevant to the GSX. Fortunately Suzuki had seen the error in their ways, employed a real plumber and made the expansion tank correctly. There is only on tube from the cap to the bottom of the tank (no Y piece) then another tube from the top of the expansion tank for overflow.
On the GSX the expansion tank is mounted on the left side of the radiator.

I guess I should have said, my bike is a GSX.

https://photos.app.goo.gl/3IgADu6Zn0WNt1Z03

For some reason I can't embed the image

As per messages

I had same or a least similar symptoms for over 6 months after a coolant change, this time (a month ago), not at all

I've seen a garage mechanic put the exhaust sensor tube from a dyno at the radiator opening, this will pick up any exhaust gases getting into the coolant system via a crack or blown gasket.

If you can find a descent mechanic he might do this for you, he might also have a radiator pressure tester to check how much pressure it is building up.

Good luck mate, hopefully we'll see the GSX come back home and not have it traded in on that gaudy green H2 you were looking at Phillip Island.

barry_mcki wrote:I've seen a garage mechanic put the exhaust sensor tube from a dyno at the radiator opening, this will pick up any exhaust gases getting into the coolant system via a crack or blown gasket.

If you can find a descent mechanic he might do this for you, he might also have a radiator pressure tester to check how much pressure it is building up.

Good luck mate, hopefully we'll see the GSX come back home and not have it traded in on that gaudy green H2 you were looking at Phillip Island.

Definitely won't be a H2, couldn't get comfortable on it.
I got it booked in to the Bunbury dealer for the 2nd. The guy I spoke to said he had never heard of a bandit doing a head gasket. Finger crossed it might be just air in it.
Yesterday after reddog sent me some photos of the workshop manual, I think I had a bit of success with it, but won't really know until a good run.

Hopefully an air pocket worked its way around after the long trip , but it took its time if it was ....................

paul wrote:Hopefully an air pocket worked its way around after the long trip , but it took its time if it was ....................

Well I'm hoping so, but I'll let the blokes at the Bunbury dealer find out for sure

Fingers crossed it just needed a burp. You don't want the other option as that'll be expensive

reddog wrote:Fingers crossed it just needed a burp. You don't want the other option as that'll be expensive

I think I would ship it home and trade it

I'm puzzled as to why the rad is low but the bottle overflowing? (arent we all?) Make sure the coolant can siphon back to the rad when it cools. Fingers crossed for you mate.

2wheelsagain wrote:I'm puzzled as to why the rad is low but the bottle overflowing? (arent we all?) Make sure the coolant can siphon back to the rad when it cools. Fingers crossed for you mate.

Well I'm hoping the original problem was a faulty cap. The only alternative is combustion gases overpressurising the system.

Word from the mechanic at the Suzuki dealership in Bunbury is there was air around the water pump. He found the air bleed at the pump and bled off a heap of air until coolant came out. He checked everything else out and can't fault it.
Pick the bike up in the morning so I guess I'll find out for sure in the coming days. Fingers crossed.

That sounds promising 

So it seems that all is still not good. Coolant is still slowly filling up the expansion bottle.

Today after a 400k ride, got back at 4:30, 7:30 now just checked the bottle, coolant now 30mm over what it was and system still under some pressure.
In the morning I'll check it again. Then I'll re bleed the water pump.

That's normal for the radiator to push coolant into the bottle as the motor gets hot and the coolant expands, but it should return what it pushes out back into radiator when the motor cools down which could take some hours, as long as the level in the bottle is back to where it started when cold then that's normal, if  the bottle was completely full after a ride then you do have a problem

What's it like first thing in the morning from dead cold?

So I checked it this morning, the level had dropped back a bit but not back to where the mechanic had set it. Removed tank and checked coolant at the cap, down a little but still visible. Using an oil syringe I drew out 50ml out of the expansion tank to bring it down to the same level the mechanic set it. 10ml of this 50 went back into the cap after I checked the bleed bolt on the water pump.
I rang the mechanic in Bunbury, he thinks it's just settling down and will find it's own level.
I guess I'll just have to keep monitoring it.

the mechanic is right it will find its own level mine doesn't always go back exactly to the mark either but its always around it and sometimes back to the mark on the bottle, just set it and keep checking it but don't add or subtract coolant, like the mechanic said let it find its own level, im sure it will be fine MM

talon440 wrote:the mechanic is right it will find its own level mine doesn't always go back exactly to the mark either but its always around it and sometimes back to the mark on the bottle, just set it and keep checking it but don't add or subtract coolant, like the mechanic said let it find its own level, im sure it will be fine MM