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Rollos

Overheating. Could it be the thermostat?

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13 hours ago, Mohawk said:

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.

 

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?

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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.

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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.

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It could be possible that you have an airlock in the system and it just needs to be burped out?

 

 

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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)

 

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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:

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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

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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

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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.

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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.

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6 minutes ago, VFROZ said:

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.

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

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4 hours ago, Grum said:

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

OOps, sorry didn't realize we were talking about an 8G.

I was on my phone, and it doesn't show pictures of poster.

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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.

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1 hour ago, Rollos said:

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.

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:

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On 6/26/2019 at 7:52 PM, Rollos said:

I 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+) 

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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°. 

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On 8 July 2019 at 8:04 PM, Grum said:

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:

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.

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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?

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