6th Gen Overheating this morning, little coolant out of overflow/vent

Hi All,

I have a 2005 and it has been running fine (as far as temperature anyway) until this morning. I noticed in stop/start traffic that the temp was up to 239F. It has never gone above 228 for me before, but I only got it last November and haven't rode it in the summer yet. Now, I am in Ireland so it isn't hot. Today it is only 54F outside. Electric fan was on, and has been behaving normally. I was almost to work so I kept going. Once there (Temp still 239 after a spike at 246), I shut her down. Temp started to drop. Checked rads, right very hot front and back. Left rad same temp (judging by hand) in front, but much cooler at back - I assume due to fan. The back of the left was touchable, but after a few seconds too hot to keep fingers there.

Now - here's the thing - After putting my lid in the top box I noticed a small amount of coolant on the ground under kickstand. Small drip of coolant on one of three vent hoses was the culprit.

Any ideas for a sudden problem like this, especially with the coolant coming out of vent hose?

I'm hoping radiator cap is the issue, but am I on dream street? I might be missing something obvious... I just had her stripped down for headlight fix and a regulator replacement and not looking forward to doing it again!

Thanks a mil.

 

I'd start by checking the coolant level and either 1) pressure testing the radiator cap or 2) replacing it outright. If that doesn't solve the problem, the thermostat could be stuck closed (thermostat failures on the 6th gen are common but usually stuck open).

The shop manual has other possible causes, such as a blocked passageway, air in the system, failed temperature sensor or gauge, water pump failure, faulty cooling fan switch, faulty cooling fan.

 

Thanks. The coolant level is fine. I'm going to change the cap and hope for the best!

 

The leak from the hose is the coolant overflow vent hose. When the engine got hot the overflow filled up and spilled a bit down the hose. It is supposed to do that in very hot conditions.

Chances are you are in need of a new thermostat. Pain in the ass to get to, but easy to change once you get there. While you are at it, switch to a 50/50 coolant mix that is aluminum engine friendly(salicylate free). Make sure you get all the air pockets out when you do this. I usually run the bike for a minute or so with the radiator cap off after filling. It is also a good idea to "burp" the fan switch on the left radiator top front. Just unscrew it until coolant comes out then screw it back in. If there is a bubble here, the fan will not turn on.

The VFR is an inherently hot engine. It does not like to be stuck in traffic and will get cranky. It likes to keep moving to keep the air flowing and the temps lower.

 

Thanks,

My coolant was low (I am going to investigate the reason for that), but it's holding steady now after 2 weeks and 200km. I'm trying a new rad cap too.

At the moment, even on cool days, when in traffic the temp climbs to 224F, then the electric fan kicks in and drops it right down to 208-212, when the fan turns off. After a few minutes it climbs back to 224 and this cycle continues forever.

Is that ok/normal for a 6th gen?

Thanks!

 

yes. Completely normal.

 

Great, thanks!

 

This is all true and good but if it keeps loosing coolant, have the coolant checked for combustion gasses. This will tell you if you have a head gasket issue.

 

That is what I am really hoping is not the case! :smile-new:

 

For the cheap price, please just replace your radiator cap. I changed my coolant due to it running warm, but I didn't have the cap tested. A couple days later it leaked coolant on my rear tire and WHAM, instant insurance claim. The Honda cap will do, but you can find the same kind at auto parts store for probably a lot less.

Please read here: http://www.vfrdiscussion.com/forum/index.php/topic/76323-weird-cooling-issue/

I understand you aren't in America, but click the link and look at the specifications for the radiator cap and find one with the same pressure etc. It will save you a lot of money.

 

Me too brother!
If it's any comfort, we rarely hear about bad head gaskets on these machines in stark contrast to Hondas four wheeled beasties that just love to blow them. I swear that I could set up a shop the exclusively does Honda automotive head gaskets and piston ring changes and I could make a living at it.

 

I have on '03 Civic that I used for tooling around or letting the kid use when he's home from college. Despite "meticulous" maintenance on that car from Day 1, head gasket went at 110,000 miles.

Back to topic...