A long coolant story

[Crofty 119]

Last year in Germany after a long ride and hot town work I could smell leaking coolant, there was coolant spatter at the left side where the hose joins the water pump. I tightened the clip and it was a bit better but kept leaking. I continued the trip and it kept leaking the volume loss was minimal. It was late autumn when I got home and I was putting the bike off the road so I took off the rad and hose to inspect everything,The hose looked a bit tatty so I bought a new one and this year after doing the valves etc I replaced the hose and filled everything up with fresh coolant. I was away a month in May and it was fine, when I went away for my Sept trip I had completely forgotten about it, I was going to the Ukraine and the Black Sea, the temps were in the high 30s and the fan started to come on in town and the dreaded coolant smell was back, I was about 30 miles from the Black Sea in Moldova, I parked the bike in the hotel car park and planned to examine everything in the morning. In the morning I saw the engine/rad was covered in coolant so I took off the rad cap and could,nt see any coolant. off to the nearest garage for some distilled water and it took half a litre.I continued the tour losing coolant and refilling about 100ml every morning. I did,nt want to tighten the clips any more because I thought they would break. Anyway the fan never came on again or any temp lights so I just carried on for another 3000 miles topping up every day or so. Back home a week ago I pulled the hose off inspected the hose and stub. Nothing trapped, so I cleaned the water pump stub and hose very meticulously and refitted it. Filled up the rad till about an inch below the cap as I suspected I might be overfilling the system. Took the bike for a fast 50 mile run with plenty of 80 mph motorway running and pulled over, still leaking from the same connection. I am thinking of putting on one of those heavy duty hose clamps but am aware I might crush the hose, anyway none of the other normal jubilee clips are leaking so it should,nt need that but I am at a loss what to do next. So I thought I would post my experience to see if anyone has had anything similiar

Edited September 29, 2016 by Crofty

[Guest machinman]

That's an odd one. Is there a crack in the casting that only shows up when at a cretain temp?

Or is it over pressurising creating a forced leak. (head gasket?)

Can't think of anything else.

[Dave H 2,022]

I had a similar thing with my Audi.  There was coolant residue on one of the coolant header tank pipes but the level never went down, well I couldn't detect it anyway.

A very careful exam of the tank showed a hairline crack.  The header tank isn't under pressure but if it was it would have leaked a lot more coolant I'm sure.

[Crofty 119]

Hi    Thanks for the replies, I am going to try it one more time and if it still leaks thinks I will go down the road of your suggestions and get the system pressurised and checked. It might be something similar and the vapour is collecting around that area leading me to believe it is the hose connection. 

[Guest machinman]

Keep us all posted. Hopefully not too serious and more importantly not costly.

[howard 70]

Sorry to sound pessimistic but are you sure its not the water pump leaking? If seal goes, coolant leaks from a small hole at back of pump and runs down over hose you described. Had same problem last year following putting incorrect coolant in one year previous! I hope for your sake it's not as pump is expensive (£200)

[Derek_Mac 1,404]

Sorry to sound pessimistic but are you sure its not the water pump leaking? If seal goes, coolant leaks from a small hole at back of pump and runs down over hose you described. Had same problem last year following putting incorrect coolant in one year previous! I hope for your sake it's not as pump is expensive (£200)

 

 @ Steve: Using the wrong coolant goes for the waterpump seals, if it's not silicate free it goes for the seals.

[Crofty 119]

Howard and Derek, I just don,t know yet, I have been using coolant from wemoto, rock oil Kool. don,t know if it is silicate free. if it is pump seals I will get it sorted. The bike is on 40k now and has been a great bike. a few hundred to get it sorted will be no problem.  will keep you posted

[howard 70]

Rock oil kool is exactly what I was using prior to pump seal failure! Rock oil now offer silicate and phosphate free coolant called Iced kool which I have been using in my NC since fitting new water pump. Personally I don't think that there is enough emphasis on using correct coolant in the owners manual but once you start searching the web re silicate free coolant, Honda seems to be main topic! Hopefully you soon get it sorted if it is indeed the pump leaking? Good luck

[embee 7,288]

If you do need to change the pump please don't bin the old one. There is a chap who has sorted replacement seals for Deauville pumps, even though Honda say they are not serviceable and you need a whole new pump. He's done a mix&match job with the seal and the ceramic "polo mint" from different models.

 

A used NC pump would be an ideal basis to strip it and see if the seal is common to other Honda items and get a suitable replacement seal set sorted out. Please let me know if you end up with a scrap pump.

[Crofty 119]

thanks for the tip Howard, gives me more options to check .Murray if it comes to a duff water pump I will get back in touch.

[Guest Mac750]

Hi I had the same thing on a Honda PC800 at 50k miles. Changed the rad cap £38 how much !. Changed the hoses, conducted a pressure test on the system and found a tiny rad core leak but also under the water pump is a small hole designed to relieve pressure on the water pump seal. It was dripping a small amount when the bike was hot. An indication the water pump is getting worn. Used some expensive rad seal which repaired the small hole in the rad and changed the water pump. Take it to a friendly garage and ask them to do a pressure test £10. Check under the water pump for a tiny hole of its wet the pump needs work. I hope that helps.

[Crofty 119]

Mac   thanks for the advice   If it is still leaking after I put the stronger jubilee clips on, that my next course of action.  a pressure test.