First summer riding everyday and I'm overheating in heavy traffic when the temp is above 80°. I see the engine temp creep past 230 and start praying for a little open road to get enough airflow to cool back down. Fan is running on cue but doesn't seem to drop temp, only slows the climb a bit. Last few weeks I've had to pull over twice to let the bike cool since it went over 250. Fan doesn't run with the engine off which isn't helping. Shouldn't it be running?
Overheating. Could it be the thermostat?
44 posts Started 26 Jun 2019 Last recovered post 30 Jul 2019 Wayback Machine snapshot 9 Apr 2020
Rollos First summer riding everyday and I'm overheating in heavy traffic when the temp is above 80°. I see the engine temp creep past 230 and start praying for a little open road to get enough airflow to cool back down. Fan is running on cue but doesn't seem to drop temp, only slows the climb a bit. Last few weeks I've had to pull over twice to let the bike cool since it went over 250. Fan doesn't run with the engine off which isn't helping. Shouldn't it be running?First check your coolant level. Last year I was surprised to find mine low and it was running hot. Personally, I've never been able to see the level through the little slot. I remove the seat, pop off the cap and put a wood chop stick in to check the level. This method also allows you to check the cap - when my coolant level was low, I think it was because the rubber cap was partially lifted off the lip.
My 2014 still runs hot in traffic on hot days, but when the fans come on at 225F, it cools down to 215F pretty quickly.
Sent from my Pixel 2 using Tapatalk
How long does it typically take to hit operating temp? Another reason I'm suspecting the thermostat is it takes 3-5 minutes to get 165°
And thanks 4corsa, it looks like I've got enough coolant through the site window but I will double check by opening up the reserve
Depending on the air temperature, 3 to 5 minutes to get up to 165F sounds about equivalent to my 2014. I haven't actually timed it, but can do so if that would be helpful.
It certainly could be your thermostat, they can get stuck partially closed, but would be unusual on a bike less than 10 years old.
Sent from my Pixel 2 using Tapatalk
What is a safe/normal upper limit for operating temperatures?
VFRLondon What is a safe/normal upper limit for operating temperatures?I've heard it depends on for how long and if at high load/rpms, but if you're just stuck in traffic for 5 -10 minutes at low rpms, 230°F is ok. The fans kick in by 225°F so it really should never get to 230.
Sent from my Pixel 2 using Tapatalk
I wish the fan ran with the engine off. Any reason why it's wired not to?
8 minutes ago, RollosI wish the fan ran with the engine off. Any reason why it's wired not to?
Two thoughts on that. One would be that the fan is a large current draw and the battery is relatively small, the other is that when the engine is off the coolant is not circulating, so the fan will only cool what's in the rad, but isn't going to draw heat out of the engine. If you want that functionality, a fan override switch can be installed. Use it to force the fan on and allow the engine to idle to move the hot coolant out to the rad.
Yeah I suppose a water pump would need to be functioning too for the coolant to circulate.
8 hours ago, 4corsaFirst check your coolant level. Last year I was surprised to find mine low and it was running hot. Personally, I've never been able to see the level through the little slot. I remove the seat, pop off the cap and put a wood chop stick in to check the level. This method also allows you to check the cap - when my coolant level was low, I think it was because the rubber cap was partially lifted off the lip.
My 2014 still runs hot in traffic on hot days, but when the fans come on at 225F, it cools down to 215F pretty quickly.
Sent from my Pixel 2 using Tapatalk
How many inches below the top is the high line?
It's about an inch. But don't worry if you over fill a little, there's an overflow tube.
Sent from my Pixel 2 using Tapatalk
12 hours ago, RollosFan doesn't run with the engine off which isn't helping. Shouldn't it be running?
Fan on the 8gen has no Thermo Switch and is controlled by the ECM, so with ignition OFF Fan cannot run!
Further to what Cogswell mentioned, it probably saved Honda money in wiring and the cost of a Thermo Switch. Keeps the system simpler as the ECM already knows the Engine Coolant Temp.
Checked coolant this morning and added about 6 ounces to bring it up to the fill line. I let the bike warm up then rev'd to 5k RPM to bring the temp up to 225. No fan. 230. No fan. 240. No fan. Turned bike off.
I have Gremlins. The fan was working fine yesterday.
I booked an appointment at my local Honda for a warranty repair in two weeks. I'll be riding it like it's an airhead until then.
So now I'm thinking thermostat, and fan wiring since the fan still turns so probably not a seized fan motor.
Rollos. You sure your bike is still under warranty? Are you up to checking a few things? At least check the state of your fan fuse in the right side fuse box under your seat. Let's know if you want to check anything else or you just want to leave it to Honda.
Good luck with your bike.
I am under the 4 year Honda care I bought with the bike last year but I'd love to narrow down the issues before I bring it in. I use the bike to commute and don't want to be without it for months. Any suggestions would be welcome. I'll check the fuze this afternoon
33 minutes ago, RollosI am under the 4 year Honda care I bought with the bike last year but I'd love to narrow down the issues before I bring it in. I use the bike to commute and don't want to be without it for months. Any suggestions would be welcome. I'll check the fuze this afternoon
Ok. If the fuse is good. Then with a meter check the ground supplied to the fan relay by the ECU which should be there at around the indicated 225degF. If it's a relay issue this can be easily swapped with the headlight relay (headlight relay is only for Hi Beam operation). Also it shouldn't be a hard task to unplug the fan relay and jumper the power feed for the fan to check its operation.
Cheers.
Fuse looks good so I'll have to check the relay
So I ended up riding to work and the temp went into the 240s in heavy traffic. The fan is running. I'm not sure why it didn't run this morning.
So here's the situation:
Fan runs
Plenty of coolant.
Still overheating to the point when the idiot light comes on
Sounds like your thermostat isn't opening all the way so you're not getting full coolant flow. That or your water pump isn't working properly. There's no reason it should go that high if your fan is working.
Sent from my Pixel 2 using Tapatalk
19 hours ago, RollosI wish the fan ran with the engine off. Any reason why it's wired not to?
It does as long as it’s within it’s working parameters, the ignition is on and killswitch in run position.
9 hours ago, RollosChecked coolant this morning and added about 6 ounces to bring it up to the fill line. I let the bike warm up then rev'd to 5k RPM to bring the temp up to 225. No fan. 230. No fan. 240. No fan. Turned bike off.
I have Gremlins. The fan was working fine yesterday.
I booked an appointment at my local Honda for a warranty repair in two weeks. I'll be riding it like it's an airhead until then.
So now I'm thinking thermostat, and fan wiring since the fan still turns so probably not a seized fan motor.
Hi Rollos. Why didn't the fan come on????. Is it possible your bike isn't overheating!
The ECT Engine Coolant Temp sensor has two outputs. One to the instrument panel the other to the ECM.
It seems odd you may have faulty thermostat But why did your fan not come on per your test?
3 hours ago, GrumHi Rollos. Why didn't the fan come on????. Is it possible your bike isn't overheating!
The ECT Engine Coolant Temp sensor has two outputs. One to the instrument panel the other to the ECM.
It seems odd you may have faulty thermostat But why did your fan not come on per your test?
I might have an intermittent short in the fan relay wiring but I haven't had a chance to check yet. That's the only explanation I can think of.
The bike definitely feels like it's overheating regardless of what the temp sensor and instrument panel are telling me. I believe it when it's reading 250° because I'm roasting sitting on it. My butt temp sensor is in full agreement there..
I've pulled over a few times in the past two weeks when the instrument panel read +235 and threw it in neutral. Every time I've done that the fan was spinning but the temp kept climbing on the instrument panel. I end up hitting the kill switch around 245 and waiting for 15 minutes...
Hi Rollos.
It seems like your Thermostat is not fully opening as it should be by 203degF (or something horrendous with your water pump). So without full coolant flow your cooling fan may not be sufficient to cool your bike. However what disturbs me a bit is the fact you did a test all the way up to 240degF (115degC) and your fan did not come on!
Why not just for the hell of it swap your Fan Relay with the Headlight Relay, they are right next to each on the R/H side of your bike. You will need to carefully remove the R/H Rear Cowl.
You can then also have a good look at the Relay wiring, run some voltage checks and check continuity of the ECM wire Gr/Bu from A23 (ECM Black Plug) to the Relay Base.
If your are really keen you could test the Fan, by removing the Fan Relay and place a jumper link between Bi/Bu wire and one of the Bu/O wires with Ignition to OFF, the jumpering of these wires should start your fan up every time you make the link. WARNING - Just DON'T jumper anything to the Gr/Bu wire as this goes to your ECM.
Do you have the wiring diagram, and service manual?
Good Luck.
[image: VFR_Relays001.jpg]
13 hours ago, RollosFuse looks good so I'll have to check the relay
Put in a new/another one to rule out "looked good but was not". Donot ask why I know.... :goofy:
So it sounds to me like you have checked the coolant level in the expansion bottle, but have you checked the coolant level in the radiator ? If you bike really gets that hot, you should see a change in the level in the expansion tank as it heats up it expels excess coolant to that tank then sucks it back in when it cools again. The 8th gen is prone to radiator puncture from road debris I minor crack high up will lose coolant & fail to suck any from the expansion tank !
1. So I’d advise, check coolant level in the radiator at the fill point pressure cap.
2. Check the pressure cap seal is clean & seating correctly. I’d advise you make a note of which way round it is & replace it in the opposite direction. By this I mean look at the writing on it & replace with the writing in the other direction.
2. Run bike static & you should NOT feel heat in the rad until it’s close to operating temp when the thermostat will open & allow coolant to circulate.
3. Whilst the bike is warming, look at the front rads for any sign of leakage or steam.
4. Warm it long enough to cycle the fan 6 times, as in fan on off cycles. If this does not happen then there is a fault in the system somewhere.
5. Wait for bike to cool fully, then repeat #1 coolant check.
Water cooled engines only fail to cool for a couple of reasons, namely lack of coolant or lack of flow, provided their fans work.
13 hours ago, MohawkSo it sounds to me like you have checked the coolant level in the expansion bottle, but have you checked the coolant level in the radiator ? If you bike really gets that hot, you should see a change in the level in the expansion tank as it heats up it expels excess coolant to that tank then sucks it back in when it cools again. The 8th gen is prone to radiator puncture from road debris I minor crack high up will lose coolant & fail to suck any from the expansion tank !
1. So I’d advise, check coolant level in the radiator at the fill point pressure cap.
2. Check the pressure cap seal is clean & seating correctly. I’d advise you make a note of which way round it is & replace it in the opposite direction. By this I mean look at the writing on it & replace with the writing in the other direction.
2. Run bike static & you should NOT feel heat in the rad until it’s close to operating temp when the thermostat will open & allow coolant to circulate.
3. Whilst the bike is warming, look at the front rads for any sign of leakage or steam.
4. Warm it long enough to cycle the fan 6 times, as in fan on off cycles. If this does not happen then there is a fault in the system somewhere.
5. Wait for bike to cool fully, then repeat #1 coolant check.
Water cooled engines only fail to cool for a couple of reasons, namely lack of coolant or lack of flow, provided their fans work.
I've been the only owner and never smelt or seen any evidence of a coolant leak. Wouldn't a hole in my radiator spill a ton of coolant?
Hi Rollos. Mohawk made a good point. At least remove your radiator cap and confirm you have coolant up to the top of the neck. Engine cold of course.
You can have a really small leak from a hose or the radiator and it could just burn off as steam.
Somewhat related, my Honda Civic recently wouldn't power on the rad fan. I realized the fan was physically broken, as it wouldn't turn, and the rad fan switch kicked the bucket too.
I would try to also physically move the fan by hand on your VFR to see if there's any resistance. It should move freely.
You also may want to test and/or replace the rad fan switch itself. There are a few videos on YouTube that shows how to test.
EDIT: Looks like this gen VFR doesn't have a separate rad fan switch.
It could be possible that you have an airlock in the system and it just needs to be burped out?
If you see *continuous* temps higher than 220ºF or below 180ºF then
trouble shooting is in order: and the *proper* order of items to trouble shoot are:
1)Faulty radiator cap... system should hold 1.1 pressure ratio...
2)Insufficient coolant...
3)Passages blocked in the radiator, hose or water jacket...
4)Air in the system...
5)Thermostat stuck closed...
6)Faulty temp meter or thermo sensor...
7)Faulty fan...
8)Faulty fan switch...
Engine temps below 180ºF or 82ºC is an problem... it means that the
moisture produced during combustion is not getting hot enough to
evaporate out the pipe as steam... instead that moisture will migrate
to the oil and produce a milky white contamination...
Note normal by products of combustion is water... . Every gallon of gas
creates roughly 8 pounds of water vapor... we all have witnessed water
escaping out of tail pipes on cold mornings...
The sequence of events to trouble shoot are:
1)Faulty temp meter...
2)Thermostat stuck open...
3)Faulty fan switch... (stuck on)
Hi Rollos.
There is a test you can run on the 8gen to verify fan operation. Just start your bike up stationary, side or center stand and once engine temp is above 45degC 113degF. Rev and hold the RPM to over 2000, within 10secs the fan should run and keep running until you drop the RPM back below 2000. Try it and see how it goes.
Cheers :beer:
Just checked oil in the sight glass and I'm seeing very little in there. Could it have burned off due to overheating or is this sign of much bigger issues? Trouble is I'm not sure if the bike was low on oil before it started overheating or if this is a newer development. I'm topping it off as soon as I'm back tonight. I was just about to give it an oil change before the whole overheating thing. Never had to add oil between changes before
Just got word from the Honda that it's the fan. Although it's running it's not moving enough air. They've ordered a new fan motor. This is the second time the fan motor has been replaced. Last year I had it replaced because it seized. I'm not a big fan of coincidence so if anyone has any ideas regarding why I'm running through fans faster than tires I'm all ears
Hi Rollos.
I'm still a little concerned for the Fan Relay. The tests you ran getting the engine excessively hot and the Fan did NOT come on is a concern. I just wonder wether the Relay is intermittent or developed high resistance contacts that could slow your fan down. Maybe with the replacement fan, the Relay could or should also be replaced on spec as well. Perhaps you could mention this to Honda.
Just a thought!
Good Luck and hope it's all sorted ASAP.
Cheers.
Thanks Grum! I'll make sure that's taken into consideration
The fan swithces on via the temp switch in the left radiator on the 5G and 6G.
No relay used.
The fan power is always on while ignition is on, and the ground is switchewd by the temp switch. this could be your problem.
I don't have a lot of trust on bike shop mechanics, and replacing the fan is expensive compared to the switch.
Just another thought.
6 minutes ago, VFROZThe fan swithces on via the temp switch in the left radiator on the 5G and 6G.
No relay used.
The fan power is always on while ignition is on, and the ground is switchewd by the temp switch. this could be your problem.
I don't have a lot of trust on bike shop mechanics, and replacing the fan is expensive compared to the switch.
Just another thought.
Hi VFROZ.
8gen is very different. There is no temp switch on the radiator. The ECM sees coolant temp from the ECT sensor and sends a grounding output from the ECM to a Fan Relay to energise it.
Cheers and Regards.
Grum
4 hours ago, GrumHi VFROZ.
8gen is very different. There is no temp switch on the radiator. The ECM sees coolant temp from the ECT sensor and sends a grounding output from the ECM to a Fan Relay to energise it.
Cheers and Regards.
Grum
OOps, sorry didn't realize we were talking about an 8G.
I was on my phone, and it doesn't show pictures of poster.
Talked to Honda today. They said they checked the relay and it's not showing any issues. Hopefully they're honest and the problem is entirely contained in the fan motor. Just bizarre that I've had two fail in a year of ownership.
1 hour ago, RollosTalked to Honda today. They said they checked the relay and it's not showing any issues. Hopefully they're honest and the problem is entirely contained in the fan motor. Just bizarre that I've had two fail in a year of ownership.
Hi Rollos. Hope they have it all sorted for you. But, if ever you see those heady height temperatures and the fan is not running. Swap the Fan Relay with the Headlight Relay, they are physically right next to each other.
Good Luck.
Cheers :beer:
Rollos, 6/26/2019 at 7:52 PMI wish the fan ran with the engine off. Any reason why it's wired not to?
My 2015 does run with key in start position but kills the battery quick. you can install a delay relay inline with your fan even when key off. Delay relays can be purchased with timer delays. Its just like your light delay on your car. hard to find them to run like 5 mins after key is off. (auto part stores have them) ask them about cooling timers. ive got to 240 fan runs almost all the time (average day here lately has been 99+)
Just got her back today. Looks like everything has been sorted by the new fan (and whatever else Honda did that they haven't told me). Fan comes on and cools her down nicely and is now running with the engine off like it's supposed to (keyed off, then back on, kill switch in run position). It's 95°f here today and the highest she ran was 220°.
Grum, 8 July 2019 at 8:04 PMHi Rollos.
There is a test you can run on the 8gen to verify fan operation. Just start your bike up stationary, side or center stand and once engine temp is above 45degC 113degF. Rev and hold the RPM to over 2000, within 10secs the fan should run and keep running until you drop the RPM back below 2000. Try it and see how it goes.
Cheers :beer:
Hi Rollos. Glad it's all sorted. Have you tried this test I mentioned, I'd be keen to know if your bike does this.
Cheers.
Were you able to keep the original (faulty) fan? Just curious if there was a lot of resistance or any clicking noise when turning it by hand?
End of thread · 44 posts recovered Wayback Machine snapshot 9 Apr 2020