Coolant one, the next no more

[ragintxn03]

So as I purchased my '99 VFR about two months ago, and as I do with every bike (mostly) I go through, check all the connections, pressures, fluids, etc.

 

In my due diligence, I replace both my oil and did a coolant flush. Fast forward two weeks later, I'm sitting in traffic, and my temp does it's normal tick up to right around 170. However instead of sitting between 165-170 it starts to tick up to 180, 190, and then the light turns green. Cools back down to about 170 (normally runs 150-160 riding), and kept doing that dance until I got home. Pulled into the garage, checked the reservoir and bone dry...

 

Any suggestions as to why I had a full tank of coolant two weeks prior and now have nothing?

 

Thanks

 

Sent from my XT1254 using Tapatalk

 

 

[Terry]

You might have a leak in the hose between the coolant reservoir and the radiator, or you might  need a new radiator cap. The hose is easily checked, and a new cap is cheap. If the cap won't hold the right pressure in the radiator, it allows the coolant to boil at a lower temperature and that cause steam to blow the coolant out of the reservoir overflow. That usually is pretty obvious.  

 

Also, not unusual to have a leak in the main coolant hoses, I had to replace all of mine around the thermostat area. The evidence for that was dried coolant leaking out of the V onto the rear headers and baking on, also when washing the bike I could see the wash water was discoloured by coolant when rinsing around the engine. 

[Duc2V4]

Well problem number one, you're sitting in traffic! Being in California, you do realize you can lane split right?

 

All kidding aside, I had this happen to me on my 6 Gen and it turned out to be the radiator cap and after a few dollars to replace it, it resolved the issue. One thing to be sure to do after you replace the coolant, is to make sure you "burp" the system. The procedure is described in the Honda Service Manual (found here: 98-01 Honda Service Manual).

[Terry]

Those temperature readings are nothing to be alarmed at. If you were looking at a conventional dial gauge for temp, 180F would be around 1/4, 212 around 1/2 and 250F is the redline. With a normally functioning thermostat and airflow from riding, you ought to see 170-180 most of the time. The fan should start up around 212.

 

Actually, looking back at your post, 150-160 is actually running cooler than would be considered normal, and I would suspect the thermostat might be stuck open if that is the case. That would be unrelated to losing coolant however.

[alwaysaware]

Thanks for posting this topic.  I've been experiencing similar temp changes.  I guess ill make a stop by the Honda Dealer and pick up a new radiator cap.

[ragintxn03]

Thanks for all the feedback - give me a place to go. I didn't notice any leaking in the garage, but the comment on baking on the headers makes sense - I'll have to check there.

 

I did get the fairing off and I guess looking through the little window isn't adequate as I saw that it was just above the lower line (although that still seems to be a lot to bleed from the system since I topped it off to the Upper line two week ago). I'll double check the lines near the header and probably just replace the cap. I keep forgetting this is nearly a 20 year old bike so things are just gonna be old.

 

Thanks again everyone!

[checksix]

The  level in the reservoir may have dropped as air worked its way out of the system after your coolant change, due to insufficiently "burping". You might want to just refill the reservoir to the half way mark and then keep an eye on it for a few rides. If the level stabilizes, you're good to go.