Weird and slightly concerning coolant leak

[jchesshyre]

Since the proper cold weather has been in, my bike's developed a minor coolant leak down on the left of the engine around the front of the alternator cover gasket. It appears to be emerging either from that gasket or the joint in the crankcase around there. It only happens for a short while when starting from cold – as the coolant heats up it begins to emerge slowly (maybe one drip every 20 seconds) but once the bike's warmed up it doesn't leak at all and after I've ridden for even ten minutes there's barely a sign that there was any leakage at all.

I'm not 100% certain it's coming from one of the gaskets mentioned above but it certainly does appear to be – I don't think it's coming from the left radiator or any of its hoses. When I have a chance I'll obviously be starting the bike up from cold with the fairing removed to get a better look but it would have to be trickling down from somewhere else in a very subtle way for me not to have noticed it already looking up from below with a torch as I have done.

I wouldn't expect there to be any coolant behind the alternator cover but presumably it does run between the top and bottom of the crankcase. I REALLY hope I don't have to replace that gasket or do anything that involves taking the engine out. I've checked the relevant bolts as far as I can see for tightness but will have another look when I get the fairing off.

Has anyone had a similar issue? Any ideas as to where it's coming from? I'll try and post a photo but it might not be that helpful.

[Wicky]

water /coolant leak > http://vtr1000.org/phpBB3/viewtopic.php?f=9&t=37968

[jchesshyre]

Thanks. It's not the weep hole from the water pump or the front drain plug...

[Kev L]

I had something similar when I first got my Storm. I went over all the pipe clips, nipping them up slightly, and that sorted it. Worth a go as it's very cheap!

[jchesshyre]

Yeah good call, I think I should actually try this. Even though I think I can see where it's coming from, it's such a small amount that it could be trickling down from somewhere else in a sort of barely visible film before congregating at the point where it appears to be emerging from.

Having had a look at the diagram of the cooling system in the manual it seems as if there aren't actually coolant passages in the area where I'm looking at so (fingers crossed) it's not down to some kind of gasket failure or crack in the crankcase. Will update when I manage to sort it.

[agentpineapple]

I had something similar when I first got my Storm. I went over all the pipe clips, nipping them up slightly, and that sorted it. Worth a go as it's very cheap!

i've had a similar leak for over a year now, me and carl tried our hardest to find it towards the end of summer, even ran my bike with the tank and airbox removed, to see if we could spot the leak, tightened up a few jubilee clips, but still no joy, i just live with now, and top it up every so often...

[mwkeats]

Hi, I had a similar leak but only seemed to occur when the bike was warmed up. Same symptom of coolant dripping down over alternator casing.
It turned out to be a pinhole leak in the expansion tank....

Tested it by removing and emptying, blocked off tube and cap opening, submerging in warm water and blowing into overflow tube. Bubbles began to appear from a pinhole leak in the seam line from the moulding process.

[tony.mon]

The usual culprit is the short hose emerging from the back of the front head.
To get to it you have to remove tank, airbox and carbs.

[agentpineapple]

i even swapped over to another expansion tank, made no difference....

[jchesshyre]

Thanks for this tony.mon. I'll get the tank, airbox and carbs off this weekend and have a look at that hose.

[Stratman]

had this after someone else had been fiddling with the carbs and it was the carb heater pipe union needed tightening

[jchesshyre]

Yeah that also occurred to me. Although they're just spring clips not jubilee clips so not sure how you go about tightening them.

My issue is clearly very much borderline dependent on temperature. Now that the weather's about ten degrees warmer here today I noticed there was no leak this morning. I'll have to hope it's freezing again when I look on Saturday otherwise it might be tricky to find it, although hopefully I'll see the dried coolant...

[Stratman]

Yeah that also occurred to me. Although they're just spring clips not jubilee clips so not sure how you go about tightening them.

My issue is clearly very much borderline dependent on temperature. Now that the weather's about ten degrees warmer here today I noticed there was no leak this morning. I'll have to hope it's freezing again when I look on Saturday otherwise it might be tricky to find it, although hopefully I'll see the dried coolant...

I shouldn't have said tightening them really. I replaced them and used small jubilee clips IIRC (though this was ten years ago+!)