posted July 11, 2002 07:36 AM
Bike Overheated Got all geared up to go to the strip yesterday evening for some runs. High 70's here in Chicago. I had started the bike and let it idle for about 2 minutes in the garage while putting the chainguard on, then was on my way. The fan had clicked on while leaving, then turned off. There was traffic due to rush hour, stop & go, but I didnt notice anything weird and couldn't hear much since I had all my gear on. Happened to look down at the temp gauge which was suddenly flashing all arrows! Looked down at the rad overflow and the coolant in there was boiling. Fan was NOT on at this point. I looked on the other side and notice my bike relieving itself of its coolant in a most undignified way all over the street and onto my rear tire via the overflow hose. Shut the bike down immediately and pushed off to a gas station that I was thankfully right in front of. Pushed the bike home (I was only 1 block away due to the traffic), and assessed the situation.
After cooling down for about 2 hours, the bike was still VERY warm and the radiator was approx. 1/2 full. Overflow bottle was bone dry. Drained all coolant from the pump drain hole as well as the block drain and it looked clean and in good shape. Drained the oil expecting the worst, it was dirty but there was no water in it. Changed the oil, and went to store to pick up more antifreeze and some Red Line water wetter. I did not have a chance to pick up distilled water to refill the bike, that'll be tonight. Out of curiosity I pullled the fan switch sensor and heated it up which DID cause the fan to kick on. No apparent leaks in the system anywhere and the radiator was free from obstructions. Radiator inside looked very clean after draining, no scale/junk in there. I figure the fan was not on during the overheating as the water level in the radiator was not tripping the fan switch as it had boiled down to below the switch.
I have NEVER had a bike do this, and have had no problems with this one up until yesterday. I'll be re-filling it tonight and starting it up, maybe it was just a fluke. Has anyone else had this happen? I've ridden in much hotter weather and everything was fine. Any thoughts would be appreciated.
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2001 Silver Zx-12R
posted July 11, 2002 11:53 AM
Hmmm... That does sound like a bit of a fluke. I've driven in town in hotter temps and the fan took care of everything.
What's your mileage? If it's high, how clean is your rad? Is it full of bugs? Was the coolant level already low before you started?
I'm wondering if the fan came on at the correct time or is it coming on too late? (already over heated)
At this point the only thing I see wrong is your extended warmup. But I'm thinking the fan should have taken care of that. The only thing I can recommend is a shorter warmup and maybe replacing that fan switch or installing a fan bypass switch to turn it on manually sooner.
Good luck! -ZXtra
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The sixth sick sheik's sixth sheep's sick!
posted July 11, 2002 01:03 PM
Check the fuse to be sure. It MUST be at least partially working or the fan wouldn't have come on when you heated up the sensor. Mine did that once, the fuse was blown NEW from the factory. I did the same thing, changed oil, coolant & didn't find a problem.
Did a warm up & fan wouldn't come on. Took it to the dealer & they couldn't find it either. I gave up & bought the manual; first thing to check per the manual is the fuse. Checked it...blown! Why didn't the dealer find it the first time I brought it back?
Changed it, & bingo fan fired right up (bike off.) Fuse checked out on a VOM continuity test, so I -guess- it was only "partially blown?" I donno, but since replacing the fuse, I haven't had a problem since. Was riding hard in the twisties in 100' heat today, & no problems....
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Enjoy the ride!
02' ZRX1200
00' ZX12R sold
posted July 12, 2002 03:23 AM
Mix (use a coolant hydrometer) the coolant to just below the lowest temp. for your area (only distilled water, coolant, and water wetter). Make sure you bleed air out of system.
It seems that the fan cycling on/off can not keep the temp. from rising when it's very hot (90+) and stuck in traffic. I've installed a simple toggle switch that bypasses (Simply jump the two leads on the temp. sensor) the temp. sensor and keeps the fan running continuous (If the switch is in the normally open position the fan works normal). As soon as I see traffic I switch the fan on and the temp. stays in the normal operating range.
Needs a life
Full throttle!
Posts: One MEEEEEELLION
posted July 12, 2002 06:50 AM
You know, I've heard of this happening to a few folks over the years. Could it be a case of coolant flow not going over the fan switch enough to heat up the thermistor and turn the fan on? Man, it sure sounds worthwhile to throw a manual switch in there... I personally have never had a single prob with the fans not coming on.
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82 Gpz750, 84 Ninja 900, 2000 ZX12R (Muzzy Big Bore Kit), *another* 2000 ZX12R (Muzzy custom stroke crank 1341cc motor), 2004 ZZR1200, 2005 ZX10R, 2007 ZX14, 2008 Concours 14, 2014 Versys 650, 2014 Yamaha WR450F, 2015 Ninja H2
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posted July 11, 2002 07:36 AM
posted July 11, 2002 11:53 AM
posted July 11, 2002 01:03 PM
Why didn't the dealer find it the first time I brought it back? 
