Hi, hopefully someone can help. I usually run the bike every week until fan comes on throughout winter. Did the same today. Usual thing, revs go up to just over 2k and then slowly comes down to normal as temp bars rise to 3. Then let it run until fan came on. Just about to turn it off when I noticed coolant pouring out from under bike. Immediately turned off and as I did so noted that temp bar was right over to right side. Once turned off I could hear boiling noise for several minutes. Checked on here and having left the bike to cool I have stripped the plastic off but cannot find any sign of where the coolant has come from. The hoses under the air box look in good order and secure. Same with all the hoses from the radiator. I was unable to detect a split hose. On taking radiator cap off I found coolant topped to brim but no sign of overflow. The overflow reservoir looks in good order with no damage. It was at low mark, but may have been for some time possibly. I dare not start the bike up again in case I do damage. In fact will there be damage due to boiling noise? Any advice on what I should do will be greatly appreciated. The bike is 08 in excellent condition. Many thanks.
Coolant dump?
- Thread starter Howard
- Start date
Water pump?
It sounds like the fan was running, but the temperature gauge kept climbing, is that correct? Since the fan switch needs hot coolant circulating through the radiator to turn it on, if the fan is on and coolant is circulating its unusual for the coolant temperature to keep rising.
The common ways you would expect runaway coolant temperature would be:
1. inoperative fan (with bike stationary, no airflow to cool things)
2. thermostat stuck closed, keeping coolant from entering radiator (coolant locked into closed path with no heat dissipation capability, just keeps getting hotter)
3. low coolant level, not enough to circulate properly and dissipate heat
From your report it doesn't seem that any of these things apply, so its a bit of a mystery at this point.
Its not likely you have done any damage, given that you have a full radiator and there's evidence the fan was running and coolant was circulating. But you're going to have to run the bike again to determine what's going on with the leak. Now that all the plastic is off start it up again and watch everything closely, you should be able to determine the location of the coolant leak. After that mystery is solved, and the leak repaired, you can move on to diagnosing the cause of the overheating, if that problem persists.
edit: after posting, saw previous post about water pump. If coolant was circulating enough to turn on the fan that would probably indicate the pump is operating normally, so I ignored that initially. But, I have first-hand experience with allowing my ST1100 water pump impellers to rust away to nothing, and it still pumped enough coolant to turn the fan on occasionally. It worked normally when moving, but was flaky when stopped in traffic. Since your test was done with the bike stationary, this could possibly explain your situation as well. If you change your coolant regularly, and know the previous history of the bike, then this is low probability, but keep it in mind.
The common ways you would expect runaway coolant temperature would be:
1. inoperative fan (with bike stationary, no airflow to cool things)
2. thermostat stuck closed, keeping coolant from entering radiator (coolant locked into closed path with no heat dissipation capability, just keeps getting hotter)
3. low coolant level, not enough to circulate properly and dissipate heat
From your report it doesn't seem that any of these things apply, so its a bit of a mystery at this point.
Its not likely you have done any damage, given that you have a full radiator and there's evidence the fan was running and coolant was circulating. But you're going to have to run the bike again to determine what's going on with the leak. Now that all the plastic is off start it up again and watch everything closely, you should be able to determine the location of the coolant leak. After that mystery is solved, and the leak repaired, you can move on to diagnosing the cause of the overheating, if that problem persists.
edit: after posting, saw previous post about water pump. If coolant was circulating enough to turn on the fan that would probably indicate the pump is operating normally, so I ignored that initially. But, I have first-hand experience with allowing my ST1100 water pump impellers to rust away to nothing, and it still pumped enough coolant to turn the fan on occasionally. It worked normally when moving, but was flaky when stopped in traffic. Since your test was done with the bike stationary, this could possibly explain your situation as well. If you change your coolant regularly, and know the previous history of the bike, then this is low probability, but keep it in mind.
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ToddC
Site Supporter
Thermostat.....Stuck closed would be my guess. Had to do all three on my bikes. Your stat is nine years old now.....
ToddC
ToddC
Blrfl
Natural Rider Enhancement
Not related to your problem, but don't do this. If you're not going to take the bike out and ride it long enough to get all of the moisture blown out, starting it does more harm than good.
The engine likely got warm to the point where the radiator sent more coolant into the expansion tank than it would hold and the excess left the bike through the hose on the neck at the top of the tank. Once the engine is shut off and starts to cool, the coolant in the cooling system will contract and the void it creates will suck coolant in from the expansion tank. That's probably the source of the noises you heard.
If you have no idea how long the engine ran hot, it's possible that it was long enough to damage the cylinder heads. If a compression and leakdown test comes up okay, the engine's probably going to be fine, although you could still have problems when it gets hot or after a few thermal cycles.
Assuming you didn't damage the heads, what you describe says that the parts handling the coolant (water pump, radiator, thermostat, hoses and radiator cap) are fine. This isn't likely a thermostat stuck closed since anything that caused coolant to be dumped in that situation would leave it all over the front or sides of the engine. (That, and most thermostats fail open.)
The 1300 should be able to sit and idle pretty much indefinitely, so I'm inclined to think that the fans aren't starting when they should. The fans and temperature gauge are both driven by what the ECM collects from the coolant temperature sensor in the thermostat housing. If the temperature gauge showed hot, the ECM knew about it and will have turned the fans on. Check the obvious things first: Has the fan motor fuse blown? (And if so, what caused it?) Do the fan blades spin freely? Does the fan relay engage when 12V is applied to the coil? Is there continuity across the contacts?
If this was a regular overheating and the engine wasn't left to run in that state for very long, it's probably fine. If it was left to run for so long that damage was done, restarting it cold isn't going to do any more damage.
--Mark
Inspect the right side of the bike, just behind the radiator cap, you will find a hose that goes rearward and connects to a plastic 3 way joint (just in front of the right cylinder head) These joints are two different dia. and mother Honda uses normal screw type small hose clamps on them. They often crack due to age or over tightening them. I switch the hose clamps out with spring clamps now to prevent damage from vibration or over tightening.
Another place where coolant may come pouring out is the bottom of the overflow catch tank on the left side just behind and under the tip over cover. I have found these split and crack, or the overflow hose rots and falls off. Your T-stat may be frozen open and the coolant may have been forced out the purge hose.
Hope this helps.
Another place where coolant may come pouring out is the bottom of the overflow catch tank on the left side just behind and under the tip over cover. I have found these split and crack, or the overflow hose rots and falls off. Your T-stat may be frozen open and the coolant may have been forced out the purge hose.
Hope this helps.
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1300s overheating are extremely rare, more common to four bars or more showing is corrosion in the wire to or damage to the coolant temperature sensor. When resistance is abnormal in the wire and connector a false reading is shown. It's possible the bike never over heated and what you saw was a cold temperature startup coolant leak from hose joints at the heads and thermostat housing.
it wasn't clear in the OP if the fan turned on normally or if the fan came on at the same time he noticed it was overheating. First time I read it I interpreted it as the fan came on normally, after a re-read I'm not sure. Clarification would help.
Hi all,
Thank you for all the input. I checked the engine again and could not see where the coolant came from. All the hoses look good and clamps are tight. What I have noted is that the inner of the left lower fairing is covered in coolant so I suspect Mark has it spot on and the reservoir purged. I have put the airbox back on, filled the reservoir to high level and started her up. Straight to 2k for several minutes and then up to 2.5k for approx a minute before gradually dropping to usual 1200. Gauge at 3 bars. Sounded good. Let it run for about 20 minutes but no fan came on. I noticed that the level in the overflow reservoir had risen so turned the bike off. No boiling noise. Soooo, I am beginning to think that what I originally thought was the fan coming on was the system overheating. If this is the case am I right in thinking the dump was simply the coolant expanding under heat and then retracting to leave the reservoir at the lower mark? Therefore I probably have not damaged the engine??
I did note that the fluid in the reservoir was full of green bits. So my plan is to empty the system, remove the radiator, flush the system, check the operation of the fan and once all is well, smile and ride. Almost exactly as advised by you guys. Whilst I am at it, should I replace the thermostat?
I am going to search how to check the fan. If I dont find anything I might need to throw my self at your mercy again. Thankyou in advance.
Thank you for all the input. I checked the engine again and could not see where the coolant came from. All the hoses look good and clamps are tight. What I have noted is that the inner of the left lower fairing is covered in coolant so I suspect Mark has it spot on and the reservoir purged. I have put the airbox back on, filled the reservoir to high level and started her up. Straight to 2k for several minutes and then up to 2.5k for approx a minute before gradually dropping to usual 1200. Gauge at 3 bars. Sounded good. Let it run for about 20 minutes but no fan came on. I noticed that the level in the overflow reservoir had risen so turned the bike off. No boiling noise. Soooo, I am beginning to think that what I originally thought was the fan coming on was the system overheating. If this is the case am I right in thinking the dump was simply the coolant expanding under heat and then retracting to leave the reservoir at the lower mark? Therefore I probably have not damaged the engine??
I did note that the fluid in the reservoir was full of green bits. So my plan is to empty the system, remove the radiator, flush the system, check the operation of the fan and once all is well, smile and ride. Almost exactly as advised by you guys. Whilst I am at it, should I replace the thermostat?
I am going to search how to check the fan. If I dont find anything I might need to throw my self at your mercy again. Thankyou in advance.
My guess is that your radiator cap has failed, and the overflow came from steam entering the coolant reservoir and pushing liquid out the overflow. If the radiator cap does not hold pressure, the coolant boils at a lower temperature, and the steam produced takes up a much bigger volume than the liquid hence the overflow. A new radiator cap would be cheap and easy to replace.
The "bits" bother me. Shouldn't be any bits anywhere, of any color. That's enough of a reason to do a flush if you ask me. Someone may have done an improper mixing of coolant types or who knows.
These guys here taught me well. Parts needed are thermostat and o ring, and two copper washers for block drains.
I would pull all the plastic. Loosen the lower radiator hose and carefully let it drain into gigantic pan. Drain the two block drains and the reservoir tank as well.
Remove the radiator. Bring inside to the kitchen sink and rinse well. Clean all black paint from the inside and outside of the large pipes. Rinse the hell out of the reservoir tank.
Replace the thermostat properly with a new honda thermostat, weep hole at 12:00, and new o ring. Snug all the hose clamps everywhere. Do not over snug.
Fill radiator with distilled water and start engine. Top up radiator..give throttle some blips here and there. Top it up and put cap on. Let it run till fans cycle a few times. Plainly if they don't cycle, find out why and fix it. If your bike storage area goes below freezing it would be a real bad idea to leave distilled water in the system obviously.
So assuming the fans work, then drain the system completely again, block and all. Should be no "bits" of anything anywhere. Refill with honda blue stuff, or I use Pentosin Pentofrost A3 available at the auto zone type stores. NO SILICA. Refill burp and repeat. Let the fans cycle some. Top up the reserve tank.
The system should not be dumping anything anytime. Plus starting the bike once a week is probably not great for the bike. It fills the exhaust up with moisture but doesn't get it hot enough to burn it off. Doesn't burn off the condensation in the crankcase either, if there is any.
I don't know about the honda pipes, but my stainless BMW pipes are full of carbon steel baffles, so moisture is not my friend.
Good luck and keep us posted. USE the white courtesy phone if it's offered and needed.
These guys here taught me well. Parts needed are thermostat and o ring, and two copper washers for block drains.
I would pull all the plastic. Loosen the lower radiator hose and carefully let it drain into gigantic pan. Drain the two block drains and the reservoir tank as well.
Remove the radiator. Bring inside to the kitchen sink and rinse well. Clean all black paint from the inside and outside of the large pipes. Rinse the hell out of the reservoir tank.
Replace the thermostat properly with a new honda thermostat, weep hole at 12:00, and new o ring. Snug all the hose clamps everywhere. Do not over snug.
Fill radiator with distilled water and start engine. Top up radiator..give throttle some blips here and there. Top it up and put cap on. Let it run till fans cycle a few times. Plainly if they don't cycle, find out why and fix it. If your bike storage area goes below freezing it would be a real bad idea to leave distilled water in the system obviously.
So assuming the fans work, then drain the system completely again, block and all. Should be no "bits" of anything anywhere. Refill with honda blue stuff, or I use Pentosin Pentofrost A3 available at the auto zone type stores. NO SILICA. Refill burp and repeat. Let the fans cycle some. Top up the reserve tank.
The system should not be dumping anything anytime. Plus starting the bike once a week is probably not great for the bike. It fills the exhaust up with moisture but doesn't get it hot enough to burn it off. Doesn't burn off the condensation in the crankcase either, if there is any.
I don't know about the honda pipes, but my stainless BMW pipes are full of carbon steel baffles, so moisture is not my friend.
Good luck and keep us posted. USE the white courtesy phone if it's offered and needed.
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Replacing the coolant is always a good idea, but I think you are heading off down the wrong track with the thermostat and fans.
From your description the only place a leak came from is most likely the reservoir overflow, and you reported a boiling sound. Both point to steam entering the reservoir, and that points to the radiator cap not holding pressure. A new radiator cap is $18.
You can check the thermostat function next time you start the bike from cold. If it is working, it will hold the heating coolant in the block until it is hot enough (176F ono), then start to open and allow that hot coolant to reach the radiator. So Under correct conditions, the radiator will stay cold for a few minutes, then suddenly get much too hot to touch. On the other hand if the thermostat has failed in the open position (most do) then the radiator will be receiving warming coolant from the time the engine start, and will gradually heat up over a few minutes.
Since you are going to flush the system (per Jim's instructions) you might consider looking for other threads here describing coolant leaks. There was a detailed discussion about the OEM clamps giving up the ghost and constant tension clamps being better than the OEM. Since you are going to do all that work, you might as well read the threads and decide if you think the other clamps are worth it.
I don't like you finding 'little green bits' in the coolant either.
I don't like you finding 'little green bits' in the coolant either.
sounds like the ECU may be leaking some 1's and 0's into the coolant
Right, and the 1's are the problems. If the 0's are cheery everything is ok.sounds like the ECU may be leaking some 1's and 0's into the coolant
JimGregory....dude, you do me proud!
In addition to sealing the radiator filler, the cap's main function is act as a pressure regulating valve and allow the radiator to pressurise up to 16-20psi. This raises the boiling point of the coolant (the reverse of water boiling at a lower temp on the top of a mountain due to lower air pressure). At this pressure, the boiling point of the coolant will be 270F (which is well above the "safe" level for the bike). Once this pressure is exceeded, the excess volume is allowed to pass to the reservoir, and is then sucked back into the radiator when you shut the bike down.
If the pressure regulating valve sticks open and the radiator can't pressurise, the coolant will boil at 225F. The steam produced takes up a much bigger volume than liquid coolant, so it will spurt into the reservoir and blow liquid out through the overflow.