Radiator leak

[oldtimer03]

My 2011 Mk1 GT with 21k miles on it, has sprung a small leak somewhere around the top right hand (throttle) side of the radiator. It empties the 250ml reserve tank in about 300-400 miles (I haven't timed it). There are some threads about this but they seem to go back to 2008-14. With the rad in situ its been impossible to find the actual source of the leak, but the hoses have been double checked, cleaned, clips tightened/checked etc, by Brian Gray's Powerbiking, so it does look like its the rad itself. Static running to get it up to full temp/pressure hasn't helped. It didn't show a leak at the dealers! It's only in wind blast that the coolant leak really shows as it spreads out from the lower side panel airway. My question is, can these aluminium rad leaks be permanently fixed cost effectively (welding not using liquid rad seal, which I wouldn't trust)? Does anyone know any competent 'fixers' in the SE? Alternatively, where is the best/cheapest replacement source, (excluding secondhand, which is often just buying other peoples problems)? There is a place in Glasgow on flea bay offering heavier brass/copper copies for £294. Has anyone used these and are they a better idea than an Aluminium OEM version? Sorry for all the questions, but there is big money involved here, so I'm keen to get the forums vast experience on this one. Cheers for your help.

[jm2]

Delkevic could be worth a call; I don't know if they produce a stock replacement for the biffer or not but their replacements for othe rbikes often come in at not much over a (properly) repaired one.

Or ask at a local car rad repairers and see what they think.

Is the rest of the rad is good shape or does it all look somewhat used (then a replacement is in order) ?

[oldtimer03]

Thanks for the suggestions.Delkevic is a new idea worth an enquiry. I took the bike for a good long run yesterday and carefully monitored the leak as best I could whilst riding. Clearly it is a very slow one that seems to come from a v.small hole among the front fins at the very top offside. It seems to lose less fluid if I keep the revs down, which is kind of odd (if true in reality). In 200 miles it lost about 100-150ml.
Having scoured YouTube, it seems possible that this should be a fixable leak using some sort of putty/cement (radweld?). Either way, I’m going to persevere with trying to get a simple and cheap fix first, before I fork out bundles of notes. Thanks again for your suggestions.

[g5guzzi]

There is a firm called advance radiators who i have seen mentioned
on this forum who do radiator repairs. Not 100% sure but i think Robbo
mentioned them.
Malc

[oldtimer03]

Finally cured the annoying and small leak. I did contact Advance Rads but in the end decided that they were too far away from me, and way more expensive than taking a punt on an old fashioned radiator sealant. Googled research came up with two seeming authoritative recommendations for a product called ‘K-Seal’. (Product ref K5501 to be exact). I rang their technical office and the guy was very confident/convincing that it was safe to use on a bike, using 55-60ml from their 236ml bottle. Anyway, hours later spent accessing the radiator filter cap (thanks Honda!!), job done. Took bike up to full temperature and pressure, and hey presto, the leak has disappeared. K-Seal is stated as a permanent fix, with no need to flush the system, so am hopeful that it “does what it says on the can”. For the £8.99 it cost on Amazon, life is good again!

[jm2]

Very good.

Plus c.170mL spare should the hole open a little in time. Well worth it.

[Kevin t]

i know its a long time back, but did the rad hold out.

[oldtimer03]

Wow, yes quite a while ago. Seems the internet never dies!
Actually the radiator did seem ok for a while, but it then leaked somewhere else (the other top corner). I then decided to buy a new rad at about £500 (from memory), but I got the old original one fully repaired by the aforementioned company, as I thought it would be good to keep a rare-ish CBF1000 part alive. It think it cost around £250; (don’t hold me to that, but it was in that ballpark). I then sold it at the repaired cost. The last I heard the new owner was very happy with it. It certainly looked good to me. Would I use the sealant again? Yes I think I’d give it a go first. If it works, great. If not, it’s not a great cost.
I later sold the bike for a nearly new Kawasaki Versys 1000GT which is a great touring bike, and a keeper for as long as have the strength to manage it!

[Froggymanny]

Actually this "K-Seal" product is something to remember so this topic was definitely worth digging-up.
So - well done Kevin, and thanks Oldtimer for taking the time to reply 

One follow-up question about these leaks: never had any on any of my past bikes and you had two on yours!! Any idea on what may have caused these leaks? could these be due to a bad production set or unlucky stone hits?

Also I'm wondering if a mudguard extension could reduce the risks and is worth the investment...

[oldtimer03]

Good questions. My old biffer was utterly reliable and well looked after, being always cleaned, garaged and on ACF50 and Optimiser over winter etc. so no rust anywhere. If any fixing furred, I replaced it! OCD I reckon!
I also had a front ‘fender extender’ and Beowulf rad guard, both of which I would deem absolutely essential. The two leaks I had were most unlikely to be stone hits, because the very small leaks were from the upper corners where the ‘finned/tubed’ section of the rad is welded to the end ‘tank-like’ sections. (I hope that makes sense?). They were not obvious to find, and only the dried coolant residues gave them away. My conclusion was that it was very unlucky weld failures. My thinking was that once one corner goes, it stresses the other corner and it then goes as well. Better engineers than me may think that that’s mechanically illiteracy, but it’s just my guess. In the end, nothing was too good for my pride and joy, so a new rad it had to be. Putting brand new bits on a bike is so satisfying isn’t it? Cheers, and thanks for asking. You’ve made me miss the old girl now………….