Total Motorcycle Community Forums

I was servicing the bike ('97 EX500) myself. I got the spark plugs out and was removing the coolant hoses to get at the valve cover. When I removed the first hose it dunked a lot of coolant inside the first cylinder. I was very careful with the second one but still spilled some coolant in the second one. Now the cylinders are full of green coolant. I tried to crank the engine by hand to get some of the coolant out but there's still a lot left in it.

How much trouble am I in? Can I get the engine running without further disassembly?

Hoo boy. You are in for a whole pile of work.

step one.

Do not crank the engine over anymore. You will run the risk of trashing your bearings if you've gotten too much coolant into the crankcase.

siphon as much of the coolant out of the cylinders as you can. The longer the bike sits, the more coolant will leak down past the rings and into the crankcase.

Step two.

drain all the oil out of the bike. refill with fresh oil. circulate it through the engine by hand cranking.

Drain and repeat.

You need to get all the coolant out of the engine asap.


for future reference, drain the cooling system first, then disconnect the coolant hoses, then pull the plugs.

Hell, you shouldn't even need to pull the plugs out to remove the cam cover.

Thanks for the reply man. I've cranked the engine a fair bit by hand to some of the coolant out. How will I know if the bearings are trashed?

Your O.K..... probably.

Leave the plugs out and spin the engine over one the starter for a few seconds. Then spray some WD-40 or other water-displacer into the cylinders. Spray lots. Turn it over with the starter in shorts burts of a few seconds (5-6), then wait 20-30 seconds and crank again. Do this until the mist stops shooting out of the cylinders. Wipe the mung you just sprayed all over your bike off and put clean, gapped plugs in. You may want to change the oil, some coolant could have leaked past the rings and into the crankcase. It should be fine after that. When you do start it, ride for awhile to get it nice and hot, to cook any lingering moisture out.

Thanks for the suggestions guys. I siphoned out the coolant and did two cycles of oil changes and cranking.

Now I can see some junk inside the cylinders - I'm guessing it got washed in with the coolant, not sure it its just dirt or worse. Someone else suggested removing the cylinder head and cleaning out the cylinders.

Should an amateur like me even try to attempt this or is it time to give up and take it to a shop?

Pulling the head seems a bit extreme.... what's a headgasket kit for your bike worth? My GSXR's is about $200... just for the gaskets, yours should be cheaper, but still.

If you've sprayed some WD into the jugs and cleaned them out that way, and it was mine, I would try starting it first. Either you'll be fine, or you will bugger the head. THEN you can worry about pulling it.

I have seen plenty of completley filled cylinders(filled a few myself ) cleaned out this way and suffer no ill effects. The only time damage has occured has been trying to turn the engine over with the plugs still in and non-compressable fluid still inside. And then it's the rods that take a chit-kickin', not the head.

If there's more than grime inside the cylinders I'm guessing I'll wreck much more than just the heads. I did the WD40 but I'm afraid to run the starter with what I see.

What exactly was IN your coolant, anyway? Besides 'grime', what else you got in there?

The WD will flush out lots of stuff that may be stuck in there, and remove the glycol from the cylinderwalls, allowing oil to cling there again instead. So long as you don't have gravel or something in there, the WD will take 95% of whatever is there with it as it leaves the cylinder when turning over. Do it 2-3 times and there's not much left.

Change the oil and filter and button 'er up.....

But it's your call.

BuzZz wrote:What exactly was IN your coolant, anyway? Besides 'grime', what else you got in there?

What he said ..

Okay then, I'll do as you suggest. At the worst I'll need to do a rebuild - should be a great learning experience.

Thanks.