Cannondaleriders

Just put in a new radiator and coolant bottle..filled the bottle with engine ice started the bike let bike idle for a while turned it off let it sit and noticed the coolent level went from level to below level. I added more coolant to fill to the line. Took the bike for a spin and coolant was leaking from the top of the bottle and trying to come throught the bottom hose the entire bottle was now full of coolant and it was overflowing. As the bike cooled down the collant level went back to normal. The top of the radiator was warm the bottom was cool ....ANY IDEAS IS IT JUST A BLEED PROBLEM? TKS!

Sounds like one of 2 problems, either bleed problem, or blown head gasket.

If this is the self bleeding system, then the o-ring at the top of then of the sleeve is bad or the sleeve could be cracked.

Did you change the impeller on the rebuild? Does your bike have the water pump cover with the bleed hole? If so, did you drill out the nipple to a larger size or verify if it was plugged?

It sounds like a bleed problem, bleed it and see what happens. It only takes a couple of minutes to bleed it.

Good luck

how if the head o-ring is bad... whould that make the top of the rad hot and the bottom cold... also wouldn't you see air bubbles if that gasket was blown.. I believe I have the self bleed.. Bike just had new wiseco piston put in, z400 bearing and new aluminum impeller..do you have any pick of the drilled out nipple? Tks

A picture won't show much. I'll try and describe. On your water pump housing at around the 2 oclock position there is a nipple that connects to a hose that goes to the upper radiator tank. Sometimes that nipple gets clogged (magnesium corrosion). If you take the hose off of the radiator you should be able to blow thru the hose into the water pump housing. If you can't, pull the housing and drill out the nipple to double it's original size. I don't remember what size bit I used.

This is off of Harrymoto.com web site:

"Cold Radiator! Loosen top front screw on the waterpump housing.

Let the air escape, when coolant starts to come out retighten. Check often!!

The bike will start cutting out if the pump has a bubble in it."


That's how to bleed the air out even if the nipple is not plugged.

Let me know if you need a picture, I can take one and post it tomorrow.

thank you will try to check on that tonight..tks to all input will let you know the outcome.

The easy way to bleed the system is to just stand the quad on its grab bar 2 or 3 times. that is how I bleed mine.

I agree, I just tried it out and it bled the air bubbles out perfectly..

You can wait for the next motor-drop to ream out the bleed port on the impeller cover. For now, you can try the above method or bleed exact same like the early quads and dirtbikes: the upper right bolt of impeller cover is the bleed screw and washer, just loosen while the coolant cap is off to purge the air.

With the bottom of radiator cool, you have not yet been "pumping" any coolant!... nice pressure test though :eek: