Z250SL radiator replacement

After replacing the forks I found the radiator was leaking. The radiator had looked suspiciously wet for a while bu I put it down to the constant damp conditions we get here in the UK for most of the year, and never really looked into it because it's easier to just park the thing up at work or home and go inside. After sitting still for a few weeks after the fork testing episode it was clear the radiator was leaking quite badly, so once again I searched ebay (what did people do before it??) and found a nice looking example from a bike with 10K miles on it for only £29.50. Once again I was in business! Obviously the price for a replacement from Kawasaki was ridiculous.

Since these rads are of particularly low quality (just like the wiring, the stator, the suspension, the brake calipers..) I'll make this more of a guide so that others will know what to do when their own rad breaks up. I don't think mine's especially prone to failure, I'm just ahead of the curve..

First, remove the silly useless belly pan. It's amazing the amount of jobs that require this thing to be taken off!

Next remove the cover to the right shoulder pad, we need access to the radiator cap so that the system will be able to drain properly.

Next it to drain the coolant, or what's left of it. The drain bolt is underneath the pump:

You will probably find that you need to undo the bolts for the bracket of the belly pan so that you can move that bracket out of the way and actually get a socket on the drain bolt. Just another little thing in the way..

This is what came out of mine after 3.5 years and 21865 miles, assuming the first owner never changed it. I can only describe it as tea?

It also smelled foul. Whatever antifreeze Kawasaki are using, it doesn't work very well.

Next up is unbolt the coolant expansion tank, that's the big white thing. You'll have to do this to be able to remove the radiator cap so that you can get a socket on the bolt holding the radiator in place on the right side..

Next remove the cover from the left shoulder pad so that you can pull the hose off (difficult..) and access the bolt holding the radiator on this side.

Undo the bolt holding the bottom of the radiator in place, this will allow the rad to swing on the top mounts and give you a little more room to get to the electrical connectors behind it.

Speaking of which, you'll need to disconnect the connectors for the temperature sensor (I think? The one on the rad) and for the fan which is nestled way in there. Best of luck!

With all that done, it's now a fairly simple case of removing whichever hoses you need to remove (depending on the replacement rad you've bought and how the breaker has sent it to you!) which is done by removing the two top bolts, one either side.

You may find it helpful to slacken the bolts that hold the reg/rec in place so that you can get a socket directly on the left side bolt.


With those two removed, the radiator should basically fall off. If it doesn't then you've probably left a hose on somewhere! Old one on the left, newish one on the right..

One of the top mounts was slightly bent/twisted on the newish radiator so I set about bending it.. I think I could have done it with my fingers. These things are made of cheese! Anyway, installation is almost the reverse of removal, just bolt it back on and fit all the hoses so your new coolant won't fall out all over the floor. Then mix yourself up some lovely blue stuff (or orange if you're fancy) and console yourself that at least it's not tea.

You will need 1.2 litres of coolant, simply fill the radiator right up to the neck (keep squeezing the hoses and leaning the bike side to side to get the bubbles out) and chuck the rest in the expansion tank when you can't fit any more. You'll have to put the radiator cap on before fitting the expansion tank in place otherwise the tank is in the way. Remember to bolt the tank into place so your precious new coolant doesn't spill everywhere!

This concludes radiator replacement for the Z250SL. If your rad starts leaking then let me know about it in the comments so that others will know what to look forward to!