Maintenance - GV250 - Radiator change Coolant - over heat warning trapped air?

[mrbios]

I drained the coolant put the drain plug in and added new 50/50 mix of Prestone antifreeze.  Ran the scoot with the radiator cap off to bleed off air until the fan came on about 8 min later.  Later in the day I got on the highway.  When I went to park I saw all 5 bars lit up on the temperature gauge wow!  No steam and the coolant was on the low side.  I opened the drain  and nothing came out.  I ran the motor and loosened the drain plug to expel air.  Things were better on the way home.  Later I did the same thing and was able to add about 5 oz of coolant.  Retested and thing were back to normal which is 2 to 3/5 bars.  The manual didn't mention anything about needing to bleed air. 

Anyone have any suggestions?  I'm glad I didn't burn up my motor.

[windwheeler]

Why in the world would you run the engine with the radiator cap off???  THAT'S where you loose the fluid in the first place. Your expansion container/bottle acts as a bleeder at the same time. 

Fill the radiator up properly, close the cap, look that there is the correct amount of cooling fluid in the expansion bottle and go for a ride. (You may idle it with cap removed until the thermostat opens and fill to top, but do not heat the engine/system up so it steams with radiator cap off.) Come back from the ride and check the expansion bottle, because from there the system will bleed and also take coolant if needed.  Open the radiator cap ONLY when the engine is truly cold if you want to check, but in all reality, you may introduce more air by just opening.

See if there is in the shop manual anywhere a "bleeder valve"; if so it should sit high.  But, I don't think so, however I have never had to check into it. The rest above is just common procedure.

Hope you did not over heat-the engine and blown a head gasket.    If with above procedure it still overheats and the coolant smells "gasy" then you may have a bigger problem now...  so let's hope it juts low on coolant and full of air with what you did so far.

[mrbios]

I followed the manual exactly.  I think there was air trapped around the water pump which is just above the drain plug.  Last night I let a little fluid out of drain plug with the cap off.  I ran the motor, turned it off and added a few ounces and now everything is fine.  Got the normal 2 to 3/5 bars even with the temp outside at 92!

I think from the design there is a potential for air to get trapped especially around the pump.  The lines are so small.  Also, I wire brushed the threads on the drain plug to reduce the thread locking compound from the factory.  I added anti-seize to the threads and it still has resistance. 

I found this post:

Well, I did the method of rocking the scoot back and forth almost all the way over....and then back on the stand. Fired it up, and it started to burp burp burp! Once it got good and warm, it was burping consistently, then I heard the MAGICAL sound....the fan kicked on!

Only one question remaining. How full does it need to be inside the radiator fill cap area? When I fill it, it promptly goes to the overflow and levels off down low. but it is running cool.

UPDATE:
I filled the reservoir but I found the best way it to remove the front plastic headlight assembly to directly access the radiator.  Fill the radiator and run the motor with cap off until the thermostat opens then turn off the motor and put the cap on and top off the reservoir.  No rocking needed and no overheating after.

[windwheeler]

It seems you are lucky you did not damage the head gasket. 

Make SURE to look at/check the overflow/expansion bottle in the next weeks where the coolant level is.  If there is still a small amount of air trapped in the system will burp it out and replace from there with coolant.

[windwheeler]

I followed the manual exactly.  I think there was air trapped around the water pump which is just above the drain plug.  Last night I let a little fluid out of drain plug with the cap off.  I ran the motor, turned it off and added a few ounces and now everything is fine.  Got the normal 2 to 3/5 bars even with the temp outside at 92!

I think from the design there is a potential for air to get trapped especially around the pump.  The lines are so small.  Also, I wire brushed the threads on the drain plug to reduce the thread locking compound from the factory.  I added anti-seize to the threads and it still has resistance. 

I found this post:

So, is your issue with the cooling 100% resolved?  It didn't take any damage?

[mrbios]

Yes, cooling problem is completely resolved.  I needed to add more coolant and work to get the air out.  Now I'm back to 2/5 bars when the temp is about 80 degrees outside.