2004 with 48k miles
On a ride today in stop and go traffic and noticed temp up into 230's.
Stopped for lunch and after heading home temp went up to 251 warning level. Pulled over, shut down and waited a few times and got home.
Checked and fan is not kicking on.
Checked fuse and it's good.
Checked coolant level (slightly low, maybe 1/2 cup) and burped.
Idled it again and at 225 no fan. Got to 233 then I shut off.
Help?
If the fuse is good then the issue is either with the wiring, the fan switch, or the fan motor. The fan switch is in the left radiator. With the ignition on and a good fuse there should be power to the switch. Make sure the contact with the switch is clean. If you run a jumper from the switch lead to ground the fan should start. If the fan does not start then check voltage. If voltage is good and the fan does not start then the fan may be bad. If the fan starts then the switch may be bad.
Whichever component seems to be bad make sure you check it carefully before you order a new part. A corroded electrical connection can make any any component seem faulty.
Good Luck
MarkDetroit thanks for the reply.
Couple things:
Ugh shit I don't know how to check what you're suggesting! I'll find someone to give me some wisdom.
In your opinion then the thermostat is not the issue?
As said before, the temperature switch is in the left side radiator. It is a goldish metal nut looking thing with a single wire coming out of it on the bottom of the radiator.
If you want to check the switch, unplug the single wire from the back side of it and use a paper clip or some other conductive item to short the wire to ground (the frame or engine case works fine). It doesn't matter what temperature the bike is, just as long as the ignition is on. I'd have to consult a wiring diagram, but the engine may have to be running.
Under normal conditions, everything up to this point is provided with battery voltage. When the temperature crosses a certain threshold, the switch will provide ground to complete the circuit. Only one wire goes in because the radiator itself is the other "wire" as the radiator is grounded.
If the fan does not turn on at this point, then we have narrowed the fault down to the fan itself or the wiring connected to it. While the wire from the thermostat is removed from the temp switch, use a volt meter to measure the voltage between this wire and ground. Your should see about 13v on the meter. If you see zero then keep working your way up the wire until you get to the fuse box until you see 13v. Once you find 13v, then you will have identified the region where the fault occurred.
If the engine is getting hot and the radiators themselves are getting hot then coolant is flowing and the fan needs to come on. So you need to solve that problem.
If your thermostat fails in a closed condition that will affect coolant flow to the radiators and they wont get very hot before the temp gauge gets to a very high temp. (Luckily thermostats usually will fail in an open condition.) If it seems the radiators are not getting very hot then the other possibility is a bad water pump.
In any case it's easy to check the function of the fan with my suggestions above. Hopefully the problem is just a corroded or loose wire or a bad switch. Those are easy fixes.
Also make sure you check for radiator fill condition at the radiator cap and not at the overflow tank.
And you may already know this but the temp that is shown on the dash gauge is for the coolant in the front cylinder head and is not the temp of the coolant in the radiator. The switch for the fan is in the radiator. You can look in the service manual to see the temp range that the fan switch should activate but that's not what you are reading on the dash gauge.
True, those are valid points as well. There may be a mechanical issue with the bike causing a lack of coolant flow to the radiator.
If the previously mentioned trick does cause the fan to kick on, then you must determine if the issue is related to the temp switch or coolant flow to the radiator.
Phew, ok thanks all! I'll be checking tomorrow and will update
Forum people!
So a buddy FaceTime walked me through checking the fan switch. Turned ignition on (but engine not started), unplugged the lead cable, stuck in a paper clip, touched other end to radiator and boom, fan turned on!
IF there's a dirty/corrosion issue with the switch, what do I use to clean it properly?
And another dumb one, if I'm cleaning it with some type of liquid chemical, what precautions do I need to take so I don't f*ck this up even more?
Thanks all!
Wayne
Wayne, What you checked with your test today was the fan. And now you know it works. That's great.
Possibly the switch is ok, but you don't know that yet.
Clean the contacts with sand paper, contact cleaner, or similar. I use Deoxit. Then make sure the cable fitting is tight to the switch fitting. I would then idle the bike to heat it up. Make sure the radiator is topped off and the radiator cap is tight! Check the radiators as the bike is idling to make sure they are warming up. By the time the display temp is up to about 225F, or so, the fan should turn on and the radiators should be hot! If, at that point, everything is hot and the fan has not come on then the switch may be bad. You can remove the switch and test it in a pot of boiling water. The switch should close at between 208 and 216F. You may need to boil antifreeze to get above 216F if the switch doesn't close at 212F (boiling H2O). It is then supposed to open back up at between 199 and 207F. (I got these #'s from the service manual)
If the radiators don't get hot when the gauge temp is about 225F then you may have a stuck closed thermostat or bad pump or....
Good Luck
Mark,
Thanks again for the info.
I'll clean the contacts per your suggestion and we'll see. Fingers crossed...
Wayne
You don't have to boil antifreeze, and probably don't want to. Instead saturated salt water @ approximately 23% by weight, boils at around 227 degrees at sea level. If you do 1 part salt added to 3x the weight of the salt as water, you will have about the right amount without wasting salt. All of the salt does not need to dissolve.
I would definitely not advise checking the temperature of the coolant by removing the radiator cap and checking directly. The boiling point of the coolant is elevated under pressure, meaning that releasing this pressure can spontaneously cause all of your coolant to boil, leading to a rocket of coolant that can cause 3rd degree burns.
12 hours ago, MadScientistYou don't have to boil antifreeze, and probably don't want to. Instead saturated salt water @ approximately 23% by weight, boils at around 227 degrees at sea level. If you do 1 part salt added to 3x the weight of the salt as water, you will have about the right amount without wasting salt. All of the salt does not need to dissolve.
Salt is a great idea to elevate water temp to approach the switching temp of 216! And a bonus - you can do it while your wife is home - LOL.
You may only have air trapped where the thermoswitch screws into the radiator.
Download the service manual if you haven't already and perform the air purging protocol.
There are probably videos on YouTube which take you through this and all the other checks, tips and tricks mentioned above.
One tip I will mention is tapping the edge of the radiator with a rubber mallet when purging or even just with the bike warmed up close to fan operating temp... Might dislodge any trapped air / bubbles.
Air around that thermoswitch means it just isn't getting a proper read on the coolant temperature as it is not properly immersed in said coolant.
MarkDetroit, 5/19/2017 at 4:02 AMSalt is a great idea to elevate water temp to approach the switching temp of 216! And a bonus - you can do it while your wife is home - LOL.
Or use some vegetable oil and cook up some chips when you are done. It would be a good idea to clean the switch of any residual coolant before you do that, but ethylene glycol is not THAT toxic. Actually, it is less toxic than table salt (but a lot easier to ingest in large quantities).
Ugh...
Cleaned the contacts and fan did not start when attached to the switch.
Bought a new switch, installed and ran engine - still no fan.
Once it cools down I'll do another fill/burp.
I burped/filled the system - nada, no fan.
I actually did the thing where I used a paper clip to start the fan - fan started.
I've read to try a new radiator cap...
Any other thoughts???????
Hmmm one thought is do I need to clean the fan cable end as well?
2 minutes ago, PhongeerHmmm one thought is do I need to clean the fan cable end as well?
Well, this is a bummer.
If the fan starts when you use a paper clip on the switch lead then it should start when connected to the switch. No reason not to check and clean all connections but that's probably not the problem.
I know it's hard to judge but does the left radiator seem to be getting hot as the engine warms up? How hot is the display showing?
The radiator cap has to be tight just like in a car. It rotates till it comes to a solid stop.
The left radiator gets HOT! I checked a couple times.
I've fussed with the radiator cap. Trying to figure out how to purchase one. I thought I could at my local (around the block) O'Reilly's but they don't seem to be able to figure out a cap for my moto...
15 minutes ago, PhongeerThe left radiator gets HOT! I checked a couple times.
I've fussed with the radiator cap. Trying to figure out how to purchase one. I thought I could at my local (around the block) O'Reilly's but they don't seem to be able to figure out a cap for my moto...
It's a good sign that the radiator is hot! That should mean the pump is working and the thermostat is opening.
So you have the old switch out of the bike. You can check to see if it is good or not if you are able to check continuity - like with a digital volt meter. Do you have a volt meter? By 216 F there should be continuity. Maybe both switches are bad (LOL - i doubt it - but it's good to check.)
And the other thing is that the left radiator has to be grounded to make the switch circuit work. I don't recall if there is a ground wire attached to it or what... Likely someone else on this forum wil know without me going to look on the bike. But you need to make sure it's grounded. (Maybe the issue is that the ground wire or connection is loose or something.)
When you used the paperclip to check the fan did you touch it to the radiator or some other point on the bike?
I touched it to the radiator. Should I touch it to somewhere else?
26 minutes ago, PhongeerI touched it to the radiator. Should I touch it to somewhere else?
No - you did it right.
If the ground lead to the radiator was broken then the fan would not have started...
So, I guess I would try and test the switches... At least the old one.
It is an option to run a manual switch to the fan to see if the running fan can properly control the operating temps. But then you still will need to figure out why the fan is not starting. I need to think about this a bit more.
Mark,
First, thanks for all your help!
So a buddy and I just talked on the phone. He's a former Honda shop mechanic and race mechanic. I reviewed it all with him and he thinks there's still air in the system. He believes that since the temp got up to 250 a couple times that the boiling created more air pockets.
Thoghts?
Anyone with magic concerning getting "all" the air out?
Marooncobra, 17 January 2016 at 10:03 AMMate,
Get yourself a spill free coolant funnel ( see photo) and connect using the correct cap which comes with the kit. You can then fill the bike with coolant and run it up watching all of the air come out through the funnel. As the coolant gets warm it will rise in the funnel, air will come out as large bubbles and then as small almost fizzy bubbles as the thermostat opens and all of the air is released. You will see the level of coolant in the funnel drop slightly as the thermostat opens. I run the bike like this mainly at idle but every so often I find if you turn the bike off, air is released as the flow has stopped. Restart the bike and idle again and continue until all air has been released. It can take a while and at times you will feel that you have a leaking head gasket as towards the end you get loads of really small fizzy air coming out. It does stop eventually. You can then let the bike cool completely, with funnel still connected, that will allow all of the coolant that is still in the funnel to fill the system as the water cools.
Once totally cooled take the bike off the side stand and lean the bike right over, with the funnel at the highest point, to ensure all of the air has come out of the second radiator as the front hose that connects the two radiators is not a straight hose and air collects in there as well as the top second radiator where the thermo switch is to operate the fan. Once done, remove and fit your radiator cap. Job done.
Ok latest in this saga...
Bought the spill proof funnel and ran the "cycle" twice -- set it up, ran moto, revved a few times, tipped to the left.
Going to do one more cycle but so far no fan turn on
Bike must be on sidestand during entire purging procedure. Not sure if you just tipped it at the end or not.
I have found I have needed to protect all wiring and connectors near right radiator spout and let it spew a bit with some good blips of throttle, once the temp is up to where the thermostat (not thermoswitch) should be fully open, then cut ignition. Let it cool with cap off, refill radiator and overflow bottle. Of course going too far with it can lead to more air getting in so it's a fussy business. Careful not to burn yourself.
I'm convinced it's air trapped around the thermoswitch.
You've demonstrated the fan and wiring are OK.
You've installed a new switch (unless it's bad from the factory, improbable but not impossible).
Have you tried my suggestion of banging the radiator to dislodge any air when it's up to fan operating temp? This is once cap is back on as at that temp, otherwise, it would overflow.
Also bang radiator while doing purging procedure.
Frustrating
Edit: I see you have spill proof funnel.
2 hours ago, PhongeerOk latest in this saga...
Bought the spill proof funnel and ran the "cycle" twice -- set it up, ran moto, revved a few times, tipped to the left.
Going to do one more cycle but so far no fan turn on
When you did this did much air come out of the system? As mentioned in my procedure you have to let the bike cycle through the thermostat opening fully. Once cool the water level would have dropped in the funnel and this is when I tip the bike fully over to the left. Almost so the fairing is 5 inches from the floor to ensure that pocket of air, that can trap in the top of the radiator, can be burped out across the cross over radiator hose and out of the filler point. If after this you still don't get the fan operating I would suggest you have either a faulty switch or an electrical issue with the circuit.
I have fitted a Davis Crag digital fan switch http://daviescraig.com.au/product/digital-thermatic-switch-kit-12-24v-0444/digital-thermatic-switch-kit-12-24v-0444 which allows me to adjust the temp the fan can operate so the OEM fan switch is now redundant. I have mine switching on when the temp in the first radiator hits 95 degrees centigrade.
My Honda shop/race mechanic friend walked me through the burping scenario. After doing the no spill coolant funnel and running a few cycles I went for a ride on the highway. I realized the problem is not the fan...
Normally on the highway my temp stays around 180'ish. Yesterday (and a couple Sundays ago when this all surfaced) the temp raced right past 180. And the fan did not start.
We believe there's an issue with the thermostat. Or maybe the water pump. Thoughts?
Both radiators feel hot to the touch and the hose from the top of one radiator to the other is hot to the touch. Could this be coming from the heat of the engine itself?
I'm thinking I'm ready to take it into the real shop...
Sounds like thermostat is working and pump is working if both radiators are hot after 78-80 degrees C as this is when the thermostat opens and allows the pump to circulate the coolant around the system. You can test this by starting the bike from cold and watch the temp gauge whilst touching the radiator with the fan switch in. It should remain cold until the thermostat opens at between 78-80 degrees C. On opening initially you will see the temp drop again as that cold slug of initial water from the radiators cools the engine slightly. if this occurs then both the thermostat and pump are working. If you have burped all of the air out of the system it suggests you have some electrical issue as you have said both radiators are hot after running the bike for a period. If you have an OEM switch fitted in the radiator then the fan should be switching the fan on around 102 degrees C
If you had access to an IR thermometer, you could measure the radiator temperature near the thermoswitch, that would allow you to confirm whether that area was above the switching temperature.
When you installed the thermoswitch, have you used a thread tape or other insulating material that might be preventing the switch from forming part of the path to ground? You could check continuity from the switch body to the radiator or back to the green wire in the 2P connector for the radiator fan. If there's no continuity here, it won't matter if the switch works or not.
Personally I'm not a big believer in the desperate need to burp these systems; by design, they have some good air displacement systems in place, and I've never done more than fill the system one the sidestand, waggle the bike around a bit, start the engine and blip the throttle a few times before topping off and fitting the cap Same applies to my VTR1000F which uses the same radiator setup.
If your bike normally runs around 180F then your thermostat is probably OK. The other check is to start the bike from cold, and keep a hand on the right radiator. If it stays cold for a few minutes then suddenly gets too hot to touch, then the thermostat is OK. If it slowly heats up from the time the bike starts, it is stuck open.
I would also suggest confirming the radiator cap is holding pressure properly, a symptom of a fault is bubbling through the reservoir when the bike is over 235F.
Thanks again for all the help and wisdom.
Want to clarify though:
Normally my temp stays at around 180 degrees when on the highway. The last two times I've ridden at highway speeds, the temp did NOT linger at 180 but went all the way to 250 and the warning light came on.
And both times the fan did not kick on at 225.
Thoughts???
Back to the thermostat I would think, it might be jammed shut, and will prevent/slow coolant from getting out to the radiators, hence they won't be getting as hot as the engine and the thermoswitch won't trigger the fan. Pulling the thermostat out requires removal of the throttle bodies and associated hoses, a no-fun job that you won't be in a hurry to repeat. If you can borrow or buy an IR thermometer (e.g. like this http://www.ebay.com/itm/DT8260-Non-Contact-LCD-Digital-IR-Laser-Infrared-Thermometer-Temperature-Gun-/332234976254?hash=item4d5abf6bfe:g:YKkAAOSw~OdVWuHN) you can read the radiator temperature directly and see if it is close to the engine temp, if the rads are much lower that would point to the thermostat being closed.
I've also read one instance where the drive coupling to the pump had sheared and gave a similar result (no coolant being pumped to the radiators), but I think that is a very isolated case.
This is a challenging problem. It certainly seems as though the fan switch is not the problem. But before I pull the thermostat I would make sure the switch does work by testing it out of the bike (in the kitchen). And then I would take the pump apart to make sure the impeller or drive coupling are not damaged or free spinning. Those are the easy things.
Then possibly the problem is the ECT sensor (engine coolant temp sensor) that sends the coolant temp signal to the dash and ECU. Maybe the engine is not getting excessively hot at all but the ECT is sending bogus info... Unfortunately you have to pull the throttle bodies to remove the ECT sensor from the head to test it. So when you do the thermostat, and if it doesn't look or test bad, make sure you check the ECT before putting it all back together.
I really don't see how the thermostat has anything to do with the fan not working. They are two independent phenomena. I do understand that hot coolant must be flowing past/around the thermoswitch for it to turn on, but the op seems to have confirmed the left radiator gets hot.
If the water pump weren't working he would have other symptoms of overheating in extremis as well as late or no actuation of the fan. He didn't mention that.
When burping with the cap off, you can see the coolant flowing according to revs, thus confirming the pump is working and thermostat is open.
It keeps coming back to your fan not turning on when the temp reading on your gauge cluster says it should.
I would primarily suspect an issue with the fan and/or its associated wiring.
At a long shot it could be as someone mentioned, that the reading displayed on your instrument panel (gauge cluster) is erroneous misleading you to think the fan should be on when it shouldn't, though I seriously doubt this. Still, if you wanted to check out that possibility, it is possible to check all the associated wiring without removing the airbox and throttle body, but yes, to check the sensor itself you would have to dig in to the sensor itself on the back of the front cylinder block (in the V of the motor). I sincerely think this would be barking up the wrong tree.
You may have an intermittent fault in either the fan wiring or the fan itself. These intermittent faults are a royal PITA. Almost impossible to reproduce so as to pinpoint the exact location of the fault. Often they only raise their head in certain circumstances, such as when hot, or due to vibrations or wires moving in the wind when in motion. This is particularly pertinent when checking the fan operates by ground directly and bypassing the thermoswitch with a paperclip or wire, as we tend to do this when the bike is cold, so as not to burn ourselves, but thus not factoring in heat-provoked faults.
Unfortunately, often the most effective way of remedying such faults is to replace parts. This should always be done one by one if you really want to know which part is to blame. If you have just had enough and want it fixed you can replace all suspect parts and swallow the cost.
I understand you have already replaced the thermoswitch, so unless by freak chance you got a faulty one off the shelf, that item should now be ruled out as the culprit.
Perhaps replace the wiring in case there is a small crack or other imperfection unseen to the naked eye. Then replace the fan which might just be on its way out, occasionally and intermittently behaving or misbehaving. I would suspect the wiring first.
I also don't see what the radiator cap has to do with fan operation. You report both radiators are heating up. I assume too hot to touch after a while. I guess if the cap is faulty it could be letting air in but you would also have the issue of the coolant boiling and the overflow tube spewing coolant onto the ground, which you have not mentioned.
Otherwise you just have a stubborn bubble at the thermoswitch location and will have to get creative with dislodging it.
Phongeer
Both radiators feel hot to the touch and the hose from the top of one radiator to the other is hot to the touch. Could this be coming from the heat of the engine itself?
The Engine Coolant Temperature (ECT) sensor is found on the rearward face of the front cylinder block, in the V of the engine. It's a double whammy in that it has two thermistors (electrical resistors whose resistance is greatly reduced by heating, used for measurement and control): one provides coolant temp data to the ECU and the other sends the data to the display panel. Usually when something goes amiss with this system you would probably get intermittent low readings or no reading at all, or it might fluctuate wildly. Rarely would it show greater values but it isn't impossible. The sensor itself could be bad, but it could also be the display panel/gauge cluster whatever you want to call it. It could also be a connector or a wire.
If the bike is running ok, not running too rich or too lean, coughing, spluttering, major fuelling type issues, excessive fuel consumption,you get my drift: not running rough but smooth and as per usual, and above all, the extra set of valves come into play in VTEC mode (above 6800 rpm for 2002-2005 and above 6400 for 2006-on), then we can assume the part of the sensor providing data for the ECU is OK. Remember for VTEC to function, the ECU is programmed in such a way that certain parameters must be met and besides RPM, another is engine temp (64*C from which a certain oil pressure is assumed to actuate the VTEC system).
A quick way to check this is by removing the left side fairing, a bunch of cables should be seen coming out from the engine, under the frame. There should be a round shaped connector, between the left hand side radiator and the frame. The Yellow/Blue and Green/Orange cables send data to the ECU and the Green/Blue and Green (ground) go to the Display. If you place a 1K resistor in parallel on the display line and the Display shows 50-70*C, then the Display Panel/Gauge Cluster is OK. By default, the problem would lie in the sensor or the connector of that line. If, with the resistor in place, the display is still showing obviously erroneous temperatures, the problem would most probably lie in the Display Panel itself, or anywhere between where you placed the resistor and the panel (including the panel).
Don't forget the famous yellow (orange on 5th gens and 6th gens from 2006-on)shite quality common ground bus connector. If it's bad, as they usually are, even from factory, just a really bad design and which many of us here on VFRD can't encourage people enough to apply a fix to, if it's bad, then any and every electrical system involved with the front subharness can go haywire.
Yet I digress... I really don't think it's your temp sensor.
Sudden rising temps and a fan which won't come on usually means air in the system once the directly related elctricals have been ruled out.
Phongeer, 5/29/2017 at 1:45 AMThanks again for all the help and wisdom.
Want to clarify though:
Normally my temp stays at around 180 degrees when on the highway. The last two times I've ridden at highway speeds, the temp did NOT linger at 180 but went all the way to 250 and the warning light came on.
And both times the fan did not kick on at 225.
Thoughts???
Phong, Please let us know what you have found. We all need the education!
Thanks
Well I gave up and took it to a local shop we have a bit of connection with. I'll update what they find...
Thanks EVERYONE for your interest and help!!!!
Any Update?
Update 6/22/17:
Took the bike to a local dealership we have a bit of a connection to, Century Cycles in San Pedro. Great folks there, especially owner Tim.
They changed out the fan motor, switch and themostat. Picking up in the next day or two.
Can't wait to have it back! We have a couple trips coming up in July; a possible ride up the coast to Oregon and the Sierra Stakeout camping trip.
Thanks again to you all for your wisdom. I love this forum!
Wayne
Far out... So we don't know which one was the culprit.
Ah, according to the shop, all three items were the culprit.
They said they couldn't get the fan to work at all.
And for sure they saw the thermostat was stuck.
Sorry, I should have given more info!
7 hours ago, PhongeerAh, according to the shop, all three items were the culprit.
They said they couldn't get the fan to work at all.
And for sure they saw the thermostat was stuck.
Sorry, I should have given more info!
Hey, I thought you already had put in a new switch...
In any case it would be good to get all the old pieces back to see how they test out.
This is a timely thread. Not to hijack but I'm having a very similar issue where the fan isn't coming on and my bike is overheating. I plan to follow the guidance provided to Phong to hopefully sort out the issue on my 5th gen.
The first and easiest test is to check the fan blade can rotate freely (cold engine, power off); the side mounted radiators seem to encourage debris to lodge between the fan and shroud and that stops it rotating; I presume you have already checked the fuse?
Next up pull the wire off the thermoswitch and ground it to the frame or motor. With ignition on, this bypasses the switch so the fan should be constantly on. If you have no joy here, the pull out your multimeter and find the 2P plug that powers the fan from the harness, and check for 12v.