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Over Heated
by: speedracer - Aug 29, 2010 17:35:53 GMT -6
Post by speedracer on Aug 29, 2010 17:35:53 GMT -6
I was going to change out my vacuum and fuel lines this morning, but needed to run to the store. Needless to say the scooter over heated. Lucky to get home. Fluid coming out of overflow tank and fan came on but only after temp gauge was on hot. Let engine get cold and removed cap. Added just a few ounces of fluid, started engine let it warm up. A few minutes later a few air bubbles came to top. Added a few more ounces of fluid and put cap on. Took it for a short ride and once again it ran hot and no fan coming on. Just turned 200 miles lucky me.
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Over Heated
by: speedracer - Aug 29, 2010 17:43:06 GMT -6
Post by speedracer on Aug 29, 2010 17:43:06 GMT -6
BTW over flow tank is totally filled.
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Over Heated
by: speedracer - Aug 29, 2010 19:30:11 GMT -6
Post by speedracer on Aug 29, 2010 19:30:11 GMT -6
For the second time today I let the scooter cool down removed the cap and had to add maybe 2 ounces of fluid. Started it up, let it warm up and watched. Some fluid went to the overflow tank, but no more air bubbles so I quickly put the cap back on and let it run. The temp gauge went to the 3/4 mark and the fan came on. I keep it running, the fan stopped, but I let it continue to run making sure the fan came back on again and that's just what happened.
Tomorrow I take it to work so that will be the test. Taking a chance but what the hell I need to know if there is something else wrong with it. My trip isn't long 9 miles, but long enough to know if the problem is solved or not.
Maybe someone can explain just what makes the fan come on and how some air in the system can keep it from coming on.
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Post by jhbietz on Aug 29, 2010 20:50:45 GMT -6
I will take a stab at it. I'm not an expert on the 250's I'm here mostly to learn.
The fan is switched on bye a temperature activated switch on your motor. When the temp gets high enouf the switch closes completing the circuit between your electrical system and the fan.
As to why it doesn't work with air in the system. Air is a poor conductor of heat and it there is air around the sensors it will not heat up sufficiently to close the switch and turn on the fan.
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Over Heated
by: speedracer - Aug 29, 2010 21:18:11 GMT -6
Post by speedracer on Aug 29, 2010 21:18:11 GMT -6
Reply #3 I'm certainly no expert on the 250 compared to the 150 I owned they are night and day. I thought I had taken care of air in the system when I first changed the antifreeze, which was maybe 10 days ago. Today it burped several times so I'm wondering where did the air come from.
I do know when I first changed the fluid the fan didn't come on until I let it cool down added fluid ran the engine and after air bubbles came to the top I had to add more fluid, and the fan worked. Tomorrow I'll know for sure.
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Post by Cruiser on Aug 30, 2010 11:21:41 GMT -6
The sensor for the fan is on the bottom of the radiator and is always in the coolant unless you are completely out of coolant. Apparently, when there is air in the system the coolant will not flow properly and the coolant at the fan sensor never gets hot enough to turn on the fan even when the engine temperature is high. Since the temp sensor for the engine is located on the head or the cylinder, it will not always correlate with the radiator temp unless there is good coolant flow.
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Over Heated
by: speedracer - Aug 30, 2010 18:38:37 GMT -6
Post by speedracer on Aug 30, 2010 18:38:37 GMT -6
Cruiser, I have to agree. Any air in the system is going to throw off the sensor on the fan. I'm sure I have all of the air out of the system now. Took it to work this morning 9 miles and the fan came on about 3 times when the gauge edged close to the 3/4 mark. Funny thing on the way home tonight and no traffic the fan never came on and the temp varied from the 1/2 mark to slightly above it.
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Post by jhbietz on Aug 30, 2010 18:56:59 GMT -6
Glad to hear your up and running good again!
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Over Heated
by: speedracer - Aug 30, 2010 19:02:09 GMT -6
Post by speedracer on Aug 30, 2010 19:02:09 GMT -6
 Thanks jhbietz.... I thought my trip to work and hopefully back might be a disaster, but it worked out just fine. When you have over heating problems you become fixated on looking at the temp gauge and fan light. Not a good habit to get into.
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Post by Cruiser on Aug 30, 2010 19:40:26 GMT -6
It sounds like your system has balanced out and is running good. Happy scootin'!
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Over Heated
by: speedracer - Aug 30, 2010 20:13:47 GMT -6
Post by speedracer on Aug 30, 2010 20:13:47 GMT -6
Hey Cruiser, Yes happy scooting days for a long time I hope. Tomorrow I'm off so I'll change out all the vacuum and fuel lines and put in a new fuel filter. I noticed a few of the lines have wire around them, but Doc says throw the wire away not needed with good old American lines.
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Thanks jhbietz.... I thought my trip to work and hopefully back might be a disaster, but it worked out just fine. When you have over heating problems you become fixated on looking at the temp gauge and fan light. Not a good habit to get into.