I came home from my shop today, turned it off, left the fan running to help cool it...started it back up and put in garage...shut it down again, heard bubbling inside, time for the hose, ran it in garage, started it back up, turned the water on, then, from underneath it started dumping coolant, in goes the hose above the front fender sending cooling water over the radiator. Let it run for a bit bathing the entire engine in cooler water, no more boiling. WTF happened? This has never happened to me ever!

HUh! How many bars was it at before the first shutdown?

didn't notice!

What you should investigate here first depends on this, was it overheating while riding or only when you shutdown? A couple of questions, was ambient temperature higher than normal or did you spend a lot of time stuck in traffic? Neither one should make a difference if everything is normal but if your cooling system was already borderline this could push you over the edge. Were you low on coolant, recovery tank on left side empty? That would do it under the right conditions. How old is your coolant, typically it needs changing each 24 months, no longer than 36 months. Again, this should not cause an overheat unless you were already marginal. You said the cooling fan was on, did it kick in by itself or do you have a manual fan switch?

When you shut the engine down, coolant temperature can soar as you stop the water pump and the airflow through the radiator. If it was not overheating while riding, this tells me the basic cooling system is OK but you may have too low a pressure setting on your radiator cap. It may be venting at too low a pressure and you get a boil over. Could have been marginal for some time and you just got her a little too hot today and pushed her over the limit.

Water pump could have failed, or thermostat could be sticking closed , either will cause boil over. If the bike was cooling fine while riding though,(2 to 3 bars lit above the "C" bar) these two do not make sense.

Donny, check the condition of your radiator for damage or airflow blockage. I would then recommend you give the entire cooling system a good thorough once over. Flush the system to remove any internal corrosion products and service with a 50/50 mixture of the appropriate coolant. I buy the premixed stuff, make sure it's safe for aluminum blocks.

Check all hoses and clamps for tighness or leaks.

Crank that bad boy up and go for a ride, keep your eye on the coolant temperature. If you start going above three bars beyond the "C", something is wrong pull her over and allow it to cool down. After she cools, ride her home and we'll discuss what to do next. If the ride goes fine with noraml temperatures (2 to 3 bars lit) but it pukes coolant again when you shut down, I would replace the radiator cap with a known good one and try again.

Kruz

* Last updated by: Kruz on 8/12/2009 @ 3:10 PM *

Please check the radiator to make sure you still have some coolant left. If you dont you risk cracking the head. Also be careful with the cold water on a hot engine. As far as the over heating I would follow what Kruz stated, he really did a good job of covering the bases.

I was just wondering if any other warning signals came on the multifunc. You would probably noticed that as easy as the low gas signal unless you had a severe reflection on the display. The coolant in the engine must have been pretty hot and after it stopped circulating, it got hotter. The second start up must have heated everything up a little more. I'll bet the fanning while the motor was shut off didn't do much to cool stuff off before the second start up. Maybe your coolant needs to be changed. I know the antifreeze properties ware out, probably the cooling properties do as well. My coolant bottle says it protects to 265 degrees when mixed 50/50 with distilled water. Yours might not have a high enough boiling point if it's old.

I'm sure the garden hose helped on the radiator. There must have been one heck of a cloud of steam.

bawahahahehehe

Good points all! Thanks! I had thumbed the motor off, left the fan running while I fumbled with the garage door opener, and removing my helmet etc as it was over 100 outside. As it turns out, the level was a bit low...at least now it is! I will flush the whole thing out, and replace with good and proper coolant. I also need new tires! This thing eats 'em!

Good plan Donny, I would start with the basics like you said, make the sure the system is topped off including the coolant expansion tank. A drain, flush and refill is a good idea, I used this stuff, compatabile with aluminum blocks and radiators and all colors of coolant. Pre-mixed 50/50 so no hassles and you can pick it up at O'Reilly's auto parts.

If it was low, and that caused the problem it should work fine now. The next question I would ask myself is "why was it low". That's why I suggested going over all the hose connections and checking the release pressure on that radiator cap. A small leak will cause a significant drop in your coolant level over time. I check coolant level in the expansion tank as part of my pre-flight every day. Hope this helps and best of luck in sorting it out.

Kruz

* Last updated by: Kruz on 8/13/2009 @ 7:28 AM *

Perhaps my field-expedient fix of the radiator after getting a rock in it, and leaking has again sprung a leak?

That wouldn't suck too bad if there were cool aftermarket radiators but I've never heard of any. Have to hang a bottle on the side and put it on slow drip.

Perhaps my field-expedient fix of the radiator after getting a rock in it, and leaking has again sprung a leak?

Donny you didn't tell us you'd plugged the radiator core. Time for a new radiator, prepare to spend some serious bucks.

Kruz

Maybe some of you have read this but for those of you that haven't its good reading
http://www.bikeland.org/story.php?storyID=32272 They did have overheating problems as well as some other problems
On my bike, with really low miles my fan has come on at 3bar level and it still seams to get hot after the fan is on now it never over heated but while just sitting there for testing From cold motor to full scale (bar level)in 8 minutes
So I dont think that the overheating while siting here is unusual. Even more so after a ride. I wish we had a numbered temp guage then we would know where we were...xxx's

* Last updated by: xxxses on 8/13/2009 @ 10:58 AM *

Donny you didn't tell us you'd plugged the radiator core. Time for a new radiator, prepare to spend some serious bucks.

Kruz

bullshitt ..my JB Weld has been on my holy radiator for 3 years .and 40k miles

Donny you didn't tell us you'd plugged the radiator core. Time for a new radiator, prepare to spend some serious bucks.

Kruz

bullshitt ..my JB Weld has been on my holy radiator for 3 years .and 40k miles

To borrow one of your favorite phrases..cheep azzz! Yours may still be on there but that doesn't help him... does it? Apparently his fix didn't take. Nuff said.

Kruz

* Last updated by: Kruz on 8/13/2009 @ 12:24 PM *

Yours may still be on there but that doesn't help him... does it? Apparently his fix didn't take. Nuff said.

i think you be wrong again .bcause if his rad was leaking ..he would smell that coolant at 30,000 feet cooking