Total Motorcycle Community Forums

I pulled up to a stoplight coming home from work and heard this gushing sound coming from below me and I looked down to see liquid flowing (turbulently but not really gushing) out of one of the tubes that leads down away from my bike. I looked at my temp gauge and it was all the way up in the red. I figured I'd try to make it home the few more blocks riding slowly and gently. The gauge dropped a bit to about 1/8 the way from the top while I was moving and I made it home.

Upon closer inspection the fluid was mostly clear. I can't be sure but there may have been a very slight yellow/green tint to it, which says it was engine coolant (which makes sense in light of the temperature heating up). I noticed a similar sized tube that the fluid was draining from connected to the top of the coolant hose where the coolant is supposed to be added. So I'm pretty sure the coolant was boiling and flowed out the hose to relieve pressure on the cooling system.

Now I have to wait for it to cool down before I do anything, but the first thing I'll do is pull the radiator and check to make sure everything is ok. I read a broken fan belt will stop the fluid from getting to the cyclinders, but then again if the fluid hadn't gone through the cylinders, it probably wouldn't have gotten hot enough to boil. I'll also check my coolant level and add if necessary.

What do you guys think. What should I check and what preventative maintanance should I perform to stop this from happening.

And BTW, weather.com says it was 108 degrees F in Sacramento today. Should I just not ride when it's so hot??

sounds like your bike may have overheated. Did the radiator fan come on at all? If it did not come on, there is probably something wrong with your thermostat. Once it reaches a certain temp, it is suppose to kick on the radiator fan.

More than likely your fan is electric not belt driven. I would think that a belt driven fan would cause a parasitic loss to the engine. also it would need some space to route the belt and need to be attached to some pulley to turn the belt.

My bike is old and the radiator fan is running as long as the key is in the on position. And yes, the fan was running. I heard it myself when I turned off the engine.

Has anyone else's coolant done this. I assume this isn't "normal," but it can't be catastrophic either if it's designed to work this way.

When was the last time you flushed the coolant fluid? I believe it is normal practice to do it every 2 years. Have you ever topped off the fluid with regular water when it was low? Adding regular water thins down the coolant mix and may have caused the boiling point to lower explaining what happened to your bike.

Were you in a lot of slow stop and go riding? My buddy was telling me how his bike overheated because he got stuck in traffic. The temp light came on and he didn't want to risk damaging the bike, so he just pulled over and let it cool down for a bit.

If the fan is running, it's either the water pump or the thermostat. I recently had to replace the water pump on my GL1100 and soon after the temperature sending unit because the fan wouldn't come on. The joys of having an older bike

mjmackenn wrote:The joys of having an older bike

Correction - Older -Water-Cooled- bike.

That sux dude, hope you didn't blow your head gasket.

Check what needs to be checked - specifically the thermostat/water pump. Also make sure your coolant passages are clean (Flush the system) and you have the right mix of coolant / water.

then try again!

That happened to me on my 84 VF700 before... found out that there was air in the coolant lines, I guess just a pocket of it, and it made the whole bike overheat.

Fill up your coolant, turn the bike on with the radiator cap off, the blip the throttle a bit until all the bubbles come out the top, and re-fill coolant as needed if the level drops while doing that.

Doing a full system flush is probably the best idea.

wow that is a bummer.....yep...it sure has been hot here in the wonderfull capitol of California..... I just went for a quick ride this morning...it was very nice...about 80 miles..out to Pardee lake and back.

Sure glad I do not have to worry about coolant etc...my Hog is air cooled!!!

Never had to deal with a water cooled bike, but it's anything like a car, it sounds like the thermostat staying close.
Simple test. Pull the thermostat and put it into a pot of boiling water and see if it opens. If it dosent, the part is bad.

I filled up the coolant with water and took it for a 15 minute ride around town. It's around 100 degrees here today and the little test drive had a lot of stoplights. Plus I had the RPMs pretty high a few times, so it definitely got a workout. The temp needle only about a sixth of the way up the gauge. So the bike stayed cool. I on the other hand was a different story. Even with a mesh jacket, that short ride left me sweating profusely. But I couldn't care less.