Overheating after coolant flush! No fan!! By jetjock79 (Read 973 times)

[jetjock79]

Hey everyone....just ran into an issue here with my 250b. She is a 2008, and was bought by the previous owner in 2010. I bought it four days ago, and started a complete fluid change, and overall checkout of the bike. Everything good so far, but had some issues while draining the coolant. Previous owner still had the Chinese cool aid in there, and surprisingly enough, she was running just fine on it. I wanted the real deal coolant, so I began to flush her. Opened the radiator cap (under seat just above the carb.), and then opened the coolant drain on the water pump housing (lower most screw). Fluid came out ok......and then filled her with water. Ran the scoot again with radiator cap off and drain screw screwed back in. I noticed that I wasn't getting anything from the fan turning on, or for that matter,....not being able to add in more water.

I then turned the scoot off, opened the drain screw, and then blew out all the coolant/water by using compressed air (from a weak electric blower used to blow up air mattresses) positioned on the radiator fill. Tons of old coolant came out......more than I put in. I then tried to fill the coolant up again, and she didn't take anywhere near what came out. I then started the scoot, and was able to put some more water in,.....but the fan didn't turn on. She just kept climbing up in temperature though. I repeated this process again one more time, and still nothing. Fluid does come out of the drain plug after she runs, but not a lot at all.

What's going on here? I know it could the thermostat, but how does the temperature get read on the dash, but the fan not kick on?! Please help ya'll!! Scoot has 1,000 miles.

[bobf]

Could it be time for burping?
.

[ellpee]

My thought too. In all that post I see nothing about the burping part of the process, and I can just imagine air pockets at some critical point(s) in the coolant circuit. I also don't see any indication that the fan ran in the first place, before the flush, so it's conceivable the fan, or the temp sensor, or both, are kaputt.

[robert1c]

Its not your thermostat. its the burping process that you need to go through and there is no rushing it. Search this site for "burping" adn you will find it. i have gone through this 2x. here is what i remember from the process.
1) on a cold motor fill.
2) disconnect the water line that goes to the thermostat
3) run the ingine
4) watch the moter begin to drink and refill
5) once it begins to warm the water will begin to spew from the thermostat hosing. wait till its close to a steam then reconnect it.
6) you could go for a little ride around the block to help with any air pockets.
7) park it and let it cool BONE COLD (like over night) ***this is important ***
8) top it off and run it for a little while remember to top it off. it may begin to back up into the overflow bottle. this is OK.
it may take a few times to repeat step 7 forward but it will begin to cool.

Hope this helps.

[jetjock79]

Thanks......definitely didn't burp it, and am going to do this today. Fan and everything worked fine before the flush.......came on halfway up the temperature gauge. Now.....the temp just sky rockets and no fan or anything.....have to shut it off before it just reaches overheating. I can't really take it around the block right now or else it will just overheat, but hopefully after adding more fluid, she will do fine. How do you know when the burping process is done?

[ellpee]

I've also read stuff here about squeezing on the hoses to force out the air, so by all means do the forum search and read everything that pops up before attacking your problem.

[bobf]

JR. Back in Aug 4, 2010 you posted a thread called, JR's ENGINE COOLANT DRAINING & ENGINE BURP, on a different forum. I have a copy and if you did not keep a copy I can try to post it here, with your permission. I used it when I got my scoot and never had any problems with no water circulation.

If you did not transfer this post when starting this forum I can try to post the link where I printed it from here on your forum.

Guidance please.
.

[JR]

Sept 22, 2013 8:37:47 GMT -6 bobf said:

JR. Back in Aug 4, 2010 you posted a thread called, JR's ENGINE COOLANT DRAINING & ENGINE BURP, on a different forum. I have a copy and if you did not keep a copy I can try to post it here, with your permission. I used it when I got my scoot and never had any problems with no water circulation.

If you did not transfer this post when starting this forum I can try to post the link where I printed it from here on your forum.

Guidance please.
.

thescooterprofessor.proboards.com/thread/24/250a-coolant-drain-location-radiator   

[bobf]

Thank you JR. Now we have the official BURP on the forum.
.

[ellpee]

Gee, after all the talk about burping I don't see anything in that linked post about burping. Also don't see the second picture showing the drain plug location for the 244 engine, although I think I know where mine is.

[bobf]

I remember about reading about squeezing the hose from the pump to the radiator to help push out air bubbles. It may have been in the conversations following where that came up. Either engine and the water release is the lowest screw on the pump.

I work on getting the engine operating properly before I make sure the overflow bottle is full. When done you want the overflow bottle to be about three quarters full when cold. Too much and the fluids will get wasted as the water warms and expands and overflows the bottle.
.

[jetjock79]

Thank you all so much!! This group seems to be so helpful! Looks like I was doing everything right, but there was a stubborn air pocket in the line from the thermostat to the sensor that turns the fan on. I pulled the line until water spewed out (steamy and all), then all I had to do was reconnect her. A few turns of the throttle and the temp came right down,....then eventually the fan kicked on. Thanks all for the help!!!!! Tomorrow will flinch again and add the coolant!!

[JR]

Sept 22, 2013 16:28:29 GMT -6 ellpee said:

Gee, after all the talk about burping I don't see anything in that linked post about burping. Also don't see the second picture showing the drain plug location for the 244 engine, although I think I know where mine is.

My bad!

thescooterprofessor.proboards.com/thread/256/helix-cf-moto-coolant-drain

[ellpee]

OK, thanks. I was thinking about that hose-squeezing thing, from your steps it doesn't look like that's absolutely necessary if one does all the rest correctly.