Possible blown head gasket...

Okay so I'm pretty bummed. I've had my VFR800 only about 6 months, put about 1500 miles on it, for a total odometer of 5508.

A few weeks ago while warming up in the driveway it got hot. Coolant temp light came on and gauge read 250°F. This was the first time she got hot.

I have since diagnosed a bad cooling fan switch as the source of the problem and have since added a switch, although I'd like to put it back to stock because I don't want to have to constantly hawk the coolant temp gauge.

So ever since hitting 250°, I'll get a minute of white smoke from the pipes that goes away at operating temperature.

Also while riding I failed to turn on the fan switch (which is why I want to revert back to the stock sensor setup)(do these bikes really rely so heavily on the cooling fan?) and she hit 230° and started puking coolant from the overflow bottle.*
*to be fair it's mostly water at this point from the few times I've topped it off. I do plan on flushing the system entirely.

**So drained out the old fluid and found it was green coolant, the Honda stuff is blue. Warming up after the coolant flush as I type this...

So it sounds like a head gasket.

...or is it?

I pressure tested the cooling system and it held 16psi for over an hour both with engine cold and with engine warm.

Spark plugs look and smell normal


But there's clearly coolant getting into the combustion chamber.

Help.

 

With your pressure test I doubt you have a bad head gasket. It's very possible that there is residue in the muffler that is finally burning off because of the hot temps. At 16# pressure it should start to drop if you have a gasket problem and it didn't. I could see compression pressure getting in to your cooling system and over heating or pushing coolant out of the tank all the time. That doesn't sound like it's happening. Ride it for a while and keep an eye on it.

When it got to 250 it may have let coolant by in to the combustion chamber and resealed afterwards. I doubt it but it's a possibility. I've seen that happen before.


EDIT: the plugs look good. no contamination there.

 

Put stock switch back on, it would have go on at 230, by the time you put the switch on its all ready too Hot!

 

Hmm it is too early to say whether or not your diagnosis of a blown gasket is right. Those plugs look passable.

I assume you have already checked the oil does not look like clotted cream. If not an oil and filter change is probably a good way to check.

Usually when a head gasket goes, you end up with water in the oil or clouds of steam pouring out the exhaust which increase with temperature. Most bikes will produce some steam in the exhaust shortly after start up - this is just any water/oil residue condensed inside the exhaust boiling off. You say the smoke only lasts a minute or two before it stops - which is not unexpected.

So disecting your various comments -

The bike is still firing up and running OK - but seemingly getting very hot. - The side mounted radiators on these bikes are good for aerodynamics but are not brilliantly efficient, so the VFRs do run hot - and on really warm days they get very, very hot and need that fan to operate correctly when required - but ideally the bike needs to be moving to dump heat on hot days.

You have currently fitted a switch to control the fan. This OK as an over-ride but as an alternative to the thermostat it is probably NOT a good idea.

By implication - we are sure the fan works - you have heard the thing running?


What to do next depends on how well you know the service history of the bike and whatever documentation you got with it. Certainly a 6th Gen bike with less that 6,000 miles on the speedo is barely run-in.

I would revert the fan wiring to normal and then ride it - not idle it! OK the book suggests allowing the bike to warm-up before hitting the upper revs - but my bike has done 100k and never gets more than 10 seconds idle before I set off.

If you are still worried - then maybe..

(1) test the thermostat in the radiator is working correctly? If that has jammed, or become clogged in the closed position, then water won't flow through the radiator and temperatures will soar, and your coolant will eventually overflow. (I guess this is possible if the bike has been parked for much of its earlier life!)
(2) test/monitor the cut-in temperature for the fan is within the range specified in the service manual?
(3) consider replacing the coolant - ensuring any air is bled from the pipework. Not expensive and for a 6th Gen perhaps overdue.
(4) Consider replacing or checking the radiator cap. Not expensive and for a 6th gen perhaps overdue.

If you are really worried - revert the fan wiring to standard and then wire in your extra switch in parallel so it is available as an alternative way of activating the fan - not the only way!

Good luck - let us know how you get on.



SkiMad

 

Thanks for all your suggestions!

 

You can try this tool to confirm head gasket leak: http://www.autozone.com/loan-a-tools/block-tester/oem-block-tester/391378_0_0/

Basically you unscrew the radiator cap and put the tool in place and start and let the engine run. If the fluid in the tool turns yellow that means exhaust gases are in the coolant system, hence it has a blown head gasket.

 

SitRep:

Flushed the cooling system with proper Honda Blue and bled air from system. Temps are manageable, but I've been flipping the manual switch on around 205. I'm trying not to let it get higher than that.

I've been looking for a radiator fan switch that kicks on at 205 but could only find an aftermarket 185* switch and the OEM 220* switch (which I DO NOT want).

I ordered this one to play with, comes on at 185*F
https://www.amazon.com/gp/product/B011EDO0YS/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

 

UPDATE:
Fan thermostat is in and kicks on at 182*F, turns off at 176*F. Rode around yesterday (really hot day) and she got up to 182 and kicked on the fan but never really cooled low enough to turn the fan back off, which is a concern of mine. I'll continue to ride it out...MUCH better than the fan coming on at 230*F!

 

On a hot day I'm not surprised that it didn't drop below 176F (80C). I think that's when the thermostat opens, that or 172F (78C), either way 176F is very cool for a 6th gen. Riding on back roads on a really hot day I wouldn't be surprised if mine never dropped below 194F (90C) once it warmed up, and I'm no longer phased when it bounces off 221F (105C) in town.

 

You're right Pawnboy, the thermostat will keep the temps up around 80C/176F no matter what the fan/thermoswitch is set to do. A thermoswitch that goes off below the thermostat closing point will never turn off once it comes on.

 

It's never a good idea to warm up a bike while standing still for any longer than 3 minutes (especially air-cooled bikes) as you discovered. First thing to do on any year VFR/VF is to test the fan switch as soon as you buy the bike, assuming it's bad.

 

Yeah I'm still searching for a 205/195 or something of the sort but can't seem to find one... My options are a 182/176 or the factory 220/195 as far as I know...if anyone knows where to get a fan switch in the middle please post a link!

 

The temperature readout on the VFR is designed to dive you nuts. This biggest problem is the in-your-face digital readout. I went to Colorado on my 5th gen and the temps worried me the whole ride. Turns out it is just VFR normal. My 5th gen will go as high as 225 but the fan cools it down. It tends t run at 198 to 217 depending on the ambient air temperature.

 

I have always left it on the ambient air temp setting but since the overhead I've been hawking the coolant temp. I know they run hot but I'd like to keep mine running under 200 and no higher than 210-215 in traffic...now I'm paranoid

 

You are not alone in your paranoia. I feel it too but you can't obsess over something that the Honda engineers obviously didn't. I just bought a Chevy Cruze and it has a digital display for all kinds of car vital signs including temperature. It runs in the 210 to 214 range when running steady road speeds on a 90+ degree day. This is were my 6th gen runs. My 5th gen runs a little cooler but not by much and will climb to 224 or 225 when sitting. The fan will cool it down and that's how it is supposed to work. I think the biggest issue is the huge digital number display. It causes me to watch the numbers and worry over something Honda is not concerned about. As long as it cycles, heats up and cools down, when sitting and doesn't overheat when running highways speeds then you are golden. Just go ride.

 

So much this. If all we had was an analog needle, no one would ever post about this.

EDIT: Although I'm aware you (OP) have actually had some other trouble, warranting the post.

 

That's what I am thinking. I think the OP got the problem fixed and is now left with the nagging "it could be bad" feeling. If the cooling really bugs you then just add a manual switch for the fan. I think a second fan would have been nice or, in the case of the new VFRs a single radiator would have been good.

 

I had my 6 Gen boil over on me, twice! The first time I was on a steep hill sitting idle for a few whilst waiting for a gate to open, so I thought it was just the particular situation. I knew the fan was working and that, although my coolant was low, there was still coolant in the system. When I got home, I topped off the radiator, purged the air from the system and then added the appropriate level to the overflow container.

A day later I rode to downtown LA (re: lots of stop and go streets and freeway traffic) and when I got to my destination, someone pointed out that I was leaking something. I knew right away it was the coolant, and when I checked my engine temp it was barely 220*. My first thought was that my thermostat was bad, so I was prepping myself to swap that out but after testing the fan switch and seeing if the tstat was actually working, which it looked to be working like it should, I figured the next logical step was the radiator cap. Changed that and viola! Back to normal.

My typical setting on the gauge is air temp, but on hot days I'll set it to engine temp and I'll monitor it. I can say I did have a scare a couple of years ago, while we were riding in the Sierra Mountains, we got stuck behind a line of slow moving cars and our temps got close to 240*! Fortunately, being able to pass and keep moving, we avoided over heating on the road. As long as the bike has airflow, the cooling system seems to do its job, so IMO, monitor it but don't let it occupy your mind, just keep riding.

 

You know, I am going to replace the radiator caps on both my VFRs. Cheap insurance.

 

So, besides letting the temp run up to 230 at idle, is there another way to test the operation of the cooling fan? Today on my 1st ride, air temp was 15C (59F) and the bike stayed around 80C (185F) at highway speeds, however, in traffic I saw 101C (222F) and in the driveway at the end of the ride, 105C (230F). Needless to say, it scared the poop out of me until I learned that this is typical