93 RM 250 pushing antifreeze out the overflow tube??

[94formy]

I have a 93 RM 250 that pushes antifreeze out the overflow tube upon start up. I just got the bike from my brother a week ago and noticed the antifreeze was low so I topped off the radiator, no leaks or anything. When I started up the bike I noticed that some antifreeze was getting pushed out the overflow hose. It stopped and the bike did not heat up. I estimate it's pushing out about half a radiator full. What could cause this? I wonder if it could just be caused by a bad radiator cap? How would I test this? What other theorys do you guys have?


thanks
Josh

 

[bruno670]

More than likely you have a blown head gasket.

 

[76GMC1500]

When the bike warms, the coolant expands and has to go somewhere. If you keep topping the radiators off, it will keep pushing it out the overflow.

 

[MX86]

still.. it shouldn't push that much out. check your radiator cap and see if that's bad.. it should stop most from getting pushed out.. also did you bleed the coolant system? so there was no air inside of the radiators?

 

[griffbones]

Pressure test the cooling system. If you do not have the tester, go to your local dealer, it will only take like 5 mins to see if the system can hold pressure, and they can also test the cap in like one minute.

 

[94formy]

still.. it shouldn't push that much out. check your radiator cap and see if that's bad.. it should stop most from getting pushed out.. also did you bleed the coolant system? so there was no air inside of the radiators?

how do I go about bleeding the cooling system? it doesn't puff any white smoke and it only does it right at start up and only if i fill the radiators up.

 

[76GMC1500]

You're fine, that's expansion. If you pull the cap while the radiator is hot (not recommended), you will see that it is full to the top.

 

[94formy]

If it was expansion wouldn't it happen when the antifreeze is just warming up not when it's still cold?

 

[76GMC1500]

Yes.

 

[94formy]

then it's not expansion because the bike doesn't run long enough to even start to warm up. I'll check the radiators when its warmed up but i don't see that being it, thanks for helping though, I can use all the opinions i can get.

 

[olthesav]

change that rad cap, check head gasket as mentioned here