Where is my coolant going?
ARRRRRGGGGGHHHHHHHHHH!!!!!!
It's happening again  
I've run the Indy for 4 years now and the design of the cooling system has stayed the same. For the first 3 years it all worked fine.
Basically it's exactly the same set up as in the original bike, using mostly original components (ZZR1100).
The set up is:- out the top of the cylinder liner, ally pipe, hose, to the original thermostat, ally pipe to hose, to radiator, from the rad via an
ally pipe to the water pump, ally pipe to the other side of the cylinders, throught there and back again.
The thermostat is fitted at the very top of the bonnet, and there is a pressure cap on there, which has a spring inside it, which allows any expansion
to flow out a small 6mm pipe to an unpressurised expansion bottle. When it cools, it is supposed to suck the coolant back from this bottle into the
system.
When I parked the car up last winter, 2008, it was all fine. The first blat of the year was down to the Yorkshire Big Breakfast and it took an age to
warm up, then when it did it wouldn't cool down again.
Checked the operation of the thermostat in a cup of hot water, it opens OK.
Re-filled the system, bled it, ran it up to temp and then let it cool down again. Take the cap off and instead of the water level being at the top,
it's down by about an inch. Doesn't sound to bad, until you realise that this leaves the thermostat and the temperature sender out of the
coolant. Top it up, fine, it just sits there. Start it up without the cap on, the coolant expands and runs out the top. Let it cool down again and
the level drops.
No obvious leaks from the rad, any of the silicone hoses, or any of the ally pipes.
So I thought I had HGF. So I put some K-Seal in. Yuk. That turned the whole cooling system into an oily sticky mess, and completely sealed the 6mm
expansion hose (didn't realise this). This meant I was pressuring up the system pretty high.
Eventually one of the hoses gave way, leading to rapid cooling loss. Re-filled it and drove home. I would note that throughout this the engine pulls
as strongly as it ever did, with no drop in performance. ( I did a couple of trackdays and nearly 900 miles around Scotland).
So eventually having convinced myself that it was HGF, I took the engine out, took the head off, got it skimmed, re-did all the valves, cleaned out
the entire cooling system, cleaning every tube, hose, and flushing the rad as best I could.
Put it all back together, filled the system up, ran it up to temp, fine, let it cool down, same inch of water has disappeared. Try again, re-fill,
bleed, try again. Still exactly the same. ARRRGGHHH!!
So this time, I diagnose it is either the head or the cylinder liner that are cracked. So I fit another engine (only to find out this one's
gearbox is knackered). So I split both engines down, put my gearbox / clutch in the new block.
Put the engine back in. Fill the coolant up, bleed it, run it up to temp fine. Let it cool down, same inch of water has gone???
Try again, fill, bleed, top up, warm up, cool down, water just gone.
So even with a completely different engine, water pump and pipes I'm still losing coolant!
The only original components are the rad, which doesn't appear to have any leaks, hot or cold. And the thermostat / expansion cap.
The thermostat works OK (tested several times in pans of hot water).
If I replace the expansion cap and it solves it, I won't know whether to laugh or cry.....
|
