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Cooling system woes

I

icecadavers

Training Wheels
So it's been a while since I posted here. I'm happy to report that the problems mentioned in my last topic have been solved! It turned out the problem was a faulty pickup coil the entire time :quest: an unusual problem from what I can tell but I should have looked there way sooner than I did. In any case, finally got her out on the road again, and though the carbs need some fine-tuning, the valves may have never once been adjusted and my mismatched mufflers mean the compression is doomed to be off, I've since logged a few hundred miles without problems. Now I have a new problem :( I was sitting at a light, digging through my pocket, and when I looked up there was thick white steam billowing out from below my gas tank. The temp gauge was at maximum and then I noticed the small puddles of coolant at my feet. Luckily I was not too far from home, and when I was moving the air kept the engine cool enough to make it back. tl;dr most of the coolant exited the system in under a minute, either by extreme pressure buildup or by a failed seal. The tiny amount that remained in the overflow tank appears ok, not discolored or anything. Also, the fan and fan switch both work OK. That's what I know so far. What I'm wondering is, what possible causes are there for this situation? My understanding of the cooling system is rather basic; I am not sure what the different purposes of the temp gauge, temp sensor, fan switch and t-stat are, or how their (mal)function can cause what happened with me. Could the water pump be the culprit? I plan on testing the t-stat and temp sensor tomorrow, as well as refilling the coolant to see if I can recreate the problem (and if so, where the coolant is coming from.) For all I know it could be that the seal on the filler cap failed (it doesn't <i>look</i> bad, but...) or even a hose that finally gave up and cracked open somewhere. Meanwhile, I appreciate any advice and insight this community can provide - I'd have given up on my connie a dozen times over without you guys. I'll keep you posted.
 
As far as hoses go, the front hose, on the left (as sitting on the bike) between the headers there, tends to go first. Of course, if you are going to replace it, all the hoses have been subjected to the same time/abuse, so plan on doing all of them. I've used the NAPA hose, part # 7741, you need two of them (they are by-pass hoses for XX vehicle). When you pull the old hose off, match up the appropiate curve, cut to size. The 7741 is a thicker walled and stiff but can be used. Aother brand hose, Drive Rite, Part # C70942, sold by Advance Auto is a bit more pliable, going to use that on my next hose replacement project. Now, some owners have had issues using these hoses or dont like them. Personally, I've seen them used on two different bikes no sweat IMHO. The upper hose, from the filler neck, is unique, no substitute, need the Kawi hose for that. Murph does have a hose kit you can get, IIRC around $90, all Kawi hoses, fit right up. Not to say that is your only problem, but check that front hose. I dont believe your waterpump is "bad", once you were moving things cooled down? Normally our pump fails by marking it's territory with an oil leak, but anything is possible. There are a couple of COGger's in the Houston area that might be able to lend a hand. Did you get this years directory? HTH
 
Vic pretty much nailed it! I would take the lowers off and bring the bike up to temp as is with water in it and find out where the leak is coming from, and go from there. C.
 
Thanks for the info, guys, I believe I have it figured out. I filled the system and warmed up the engine, and as the temp gauge continued to climb the fan never kicked in, even as the needle hit red and, soon after, coolant and steam began spurting all over. The leak turned out to be a tiny crack at the top of the reservoir, at the base of the stem to which the overflow hose attaches. The real culprit, however, was actually the fan circuit fuse - which I overlooked at first because the damn thing isn't in the j-box but rather hidden behind it. As I replaced the fuse the fan spun up instantly. So now I just have to repair the crack in the coolant bottle - more a precautionary measure as I see it, but I don't want stuff getting into the coolant any more than I want the coolant getting out. I guess I'll try and wash the damn thing while I'm at it, it's so caked with gunk inside and out that it's impossible to read the level. Maybe I'll get that hose kit from Murph's, too - only $60, why not? Thanks again - wish me luck.
 
I'm a new Concours owner-1987 52k miles. I've owned it 2 weeks. I'm new to water cooled but not to motorcycles. In going through the bike I found the coolant in the resevoir was not a cheerful color and it was difficult to check the level due to brownish coolant slime on the inside of the resevoir. I was checking here for advice on flushing the system. After reading this I will replace all the hoses. The manual says to replace the washers on the coolant bleed vents if required. I have a feeling I should count on doing that. Any instructions advice on coolant system flushing and a source for those washers would be much appreciated. Also, since the coolant temerature guage is not gradiated, where should the needle usually be? Thanks!
 
David: Flushing the system is fairly easy. drain the coolant, then fill it with filtered water and 1 tablespoon of dish soap; get the bike up to temp and then run the engine for another five minutes or so. Then drain the system, and flush it through with clean filtered water a couple of times. As for the washers, I've always been skeptical about the supposed need to replace crush washers every time you remove the bolts they go on - I guess the plasticity they need to seal properly could lead to becoming deformed eventually, but I've reused washers once or twice before with no ill effect. Just, if you do, watch out for scarring and be careful not to strip any threads. Honestly, I don't know where to get new ones anyway, but I'm sure someone here will. The fan kicks in when the temp gauge is at about halfway - it's slightly different for everyone, but make a couple separate observations while riding and you'll be able to see about where yours should stop. Good luck with the new bike!
 
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