I'm totally fed up now.

I've run the ZZR engine in the Indy since it passed it's SVA in Nov 05. So that's nearly 4 years with the same cooling set up.

At some point over the winter it developed a problem in the cooling system. First few runs out this year it took an age to warm up (which I put down to very low ambient temps) and then just wouldn't cool down. I thought I had some oil in the coolant, very slight traces of mayo in the filler cap.

I stuck some K-seal in there as I didn't want to miss out any driving time. This blocked the overflow from the expansion cap to the expansion bottle

Since then I did a trackday, the FBB09 round Scotland and several other big days out. On the last day of the FBB09 in Edinburgh it got a pinhole split in one of the coolant hoses. Which resulted in a jet of hot coolant shooting about 10' across the car park and lots of steam!

Replaced the hose with new silicone and topped up, bled the system again etc.

Each time I had the same symptom, took a while to warm up, then just wouldn't cool down again. Top up the coolant in the morning, drive for a while, then when it cooled, check the coolant again, and about 100ml was missing! The expansion bottle stays at the same level?

The cooling system is as it is in the bike, apart from a slightly bigger radiator. So it goes head > thermostat > expansion cap (with overflow to expansion bottle) > radiator > pipe > water pump > block > head > etc etc.

I've drained it, bled it, flushed it through, changed the water pump, checked the water pump works, bled it. I get hot water in all the pipes / elements of the cooling system in the right order.

I've just stripped the engine down, replaced the head gasket, skimmed the head and put it all back together and I get the same symptoms.

Fill the system up, run the engine, stop the engine, take the filler cap off, 100ml of water gone.

Thing is, the engine still runs and seems to put out very decent amounts of power. I've no problem keeping up with the lads in 2.0 zetecs etc.

I've run copious quantities of water through the system as a whole (from filler cap to drain) and through all the parts individually so there are no blockages / airlocks.

What do I do?

Seriously tempted to rip the Zed out and go CEC!

Mike

2 thoughts are
Thermostat - faulty not opening at right temp hence slow warm up.
Header tank cap seal gone - allows steam out (water loss) + system cant pressurize???

Thermostat checked in hot water, opens OK. Swapped with a spare - already checked. Opens OK.

Header cap swapped with another one. No difference.

The drop in water level is rapid. With the engine warm, top it up to "full". Leave the cap off, come in, write this long tale of woe, go outside need to top up the water by 100ml.

It's not going on the floor of the garage, it isn't going into the block (oil level stays the same and isn't emulsified).

???????

Mike

water fairies?

quote:

---

Originally posted by Guinness

At some point over the winter it developed a problem in the cooling system. First few runs out this year it took an age to warm up (which I put down to very low ambient temps) and then just wouldn't cool down.
Stating the obvious, is the thermostat fitted, fitted correct way and known ot be working? Have you run it without the thermostat to see what difference it makes? Weird symptoms as it sounds like the 'stat is open sthus taking ages to get up to temp - are you driving it at the time or stationary? Is the cooling fan running during this time? And then not cooling down sounds like the thermostat is closed; again does fan kick in?

I stuck some K-seal in there as I didn't want to miss out any driving time. This blocked the overflow from the expansion cap to the expansion bottle

That and radweld comes out of satan's own arse - a bodge - who knows what else is blocked up, did you check waterways in block and hoses when rebuilding?

---

quote:

---

Originally posted by Guinness
The drop in water level is rapid. With the engine warm, top it up to "full". Leave the cap off, come in, write this long tale of woe, go outside need to top up the water by 100ml.

It's not going on the floor of the garage, it isn't going into the block (oil level stays the same and isn't emulsified).

---

That's a strange one old chap, and difficult to diagnose without looking at it. I take it that you've replaced the stat and flushed the radiator (though neither of these really give the symptoms that you are suggesting)? Are you sure that the temperature gauge is ok? The loss of water is head-scratching if it's not appearing in the header tank, which I assume is vented to atmosphere? Is the water inlet on the header tank at the bottom, or does it have a tube running to the bottom of the tank if the inlet is at the top? The cooling system should effectively find its level, pushing out a bit of water into the tank when it warms up, then drawing it back again once it cools.

Ooooh, lots of posts since I started typing my reply, which has been pretty-much answered!

Just one thought - the thermostat should have a little hole in the flange that should be at the top should the stat be laid on its side. Is this the case or have you fitted it with the hole at the bottom? If so, you'll have a chunk of trapped air in there that will expand more than the water when hot.....

Thermostat is OK. Installed the right way round with the hole at the top.

Start the engine, temp gauge climbs, thermostat housing gets hot. Then thermostat opens water flows along top pipe into rad. Rad heats up from top to bottom. After about 5 mins, rad is fully hot, bottom pipes / hoses get hot.

I know water expands when hot and contracts when cool, but not as much as I am seeing! (although I have struggled to find a % increase for a given volume / temperature increase!).

There is a bleed valve on the hot side of the thermostat, which is where the air seems to be.

i.e. the water level drop is about the same as from the top of the thermostat housing down to the hole in the thermostat! ?

I've just been out and taken all the hoses / pipework off the car and run the hose pipe through them. No blockages at all.

Mike

Just to add a curved ball thought - water pump impeller moving on the shaft when hot?
Cheers, Pewe

quote:

---

Originally posted by pewe
Just to add a curved ball thought - water pump impeller moving on the shaft when hot?
Cheers, Pewe

---

done a 'sniffer' test?

quote:

---

Originally posted by t16turbotone
done a 'sniffer' test?

---

quote:

---

Originally posted by Guinness

quote:

---

Originally posted by t16turbotone
done a 'sniffer' test?

---

?? For exhaust gases in the coolant - no, but I have just had the head skimmed and replaced the head gasket.

Mike

---

They didn't pressure test the head. I'm thinking they should have now!

The design of the big zed seems to avoid mixing water and oil. The oil is fed to the head via an external rubber hose. The excess / used oil flows back down the cam chain, avoiding all the cylinders completely.

The water jacket comes in the cylinder block, goes past the cylinders and into the underside of the head. From the underside of the head it comes straight out the side, well below the level of the cams in the head.

I guess it is possible there is a crack in the head or block.

Mike

Is it constantly losing water or is it just settling at a level it is happy with?

If you fill it when cold, run it up to temperature and then let it cool (so that it loses its 100ml) then once it is cool, run it up to temperature again does it lose another 100ml or does the level stay the same?

Some installations just seem to gather air in certain places, it could be due the the levels of the radiator and header tank being different from those of the original bike in comparison to the engine.

Duncan

quote:

---

Originally posted by dmac
Is it constantly losing water or is it just settling at a level it is happy with?

If you fill it when cold, run it up to temperature and then let it cool (so that it loses its 100ml) then once it is cool, run it up to temperature again does it lose another 100ml or does the level stay the same?

Some installations just seem to gather air in certain places, it could be due the the levels of the radiator and header tank being different from those of the original bike in comparison to the engine.

Duncan

---

I assume you're bleeding the pump as well as the thermostat housing?

It sounds like an airlock Mike.
Can you some how force fill the coolant system? I know Snap on used/still sells a coolant fill system because of the same thing.......air on the system.

[Edited on 18/8/09 by pgtips]

Its been a while since I saw a zzr engine and I can't remember what the thermostat looks like but it seems a strange arrangement to have it in an air trap like that, if there is a bleed connection on it, try connecting that to your header tank to allow it to automatically bleed.

Duncan

not sure if this helps but i had a problem with levels going up and down on my GSXR1000 engine i had moved the header tank to a new position at the front after 5 hrs of refilling a number of times
i found the problem was the distance between the top of the radiator and the header tank was to close i moved the radiator down alittle so the top of the radiator is level with the min line on the header tank
when the temp gets to 90 degrees the water expands to the max line then when the engine is switched off and cools down goes back to the min line

I'm not quite getting the water level thing - is the level dropping just when engine has warmed and then returns to previous level when cold or not? If not, then it is losing water somehow i.e. you have to keep topping the water up.

The former would indicate an air lock situation, probably.

quote:

---

Originally posted by 02GF74
I'm not quite getting the water level thing - is the level dropping just when engine has warmed and then returns to previous level when cold or not? If not, then it is losing water somehow i.e. you have to keep topping the water up.

The former would indicate an air lock situation, probably.

---

i would do a compression check mike

from what i can understand It seems to me that water only drops to a particular level?- which would suggest to me that you have a problem in the top half of the engine i.e cylinder head....do a sniffer and compression test mate

are you able to continue this process to see if the lever ever stops droipping, e.g. say you have added 1 litre?

it does sound like water is leaving the engine - once warmed up, metal expands so if there is a crack, it opens up and water gets out .... but weird hings is you would expect to see that come out somwhere.

You mention exhaust ports are water free - water about inlets? bear in mind the water can exaporate in a hot engine so in this hot weather, you won't see it as steam.

you meniotn you leave the cap off - I cannot imagine 100 ml of water evoprating out of that but ......

For clarity, here's Mike's thermostat housing. I had one similar on my Striker from a ZRX1100, though I didn't run a stat. Does the level drop if you leave the car in the garage for a few days without running it?

It's unfortunately sounding like you have a cracked head. I'm wondering if it's worth the expense of getting yours pressure tested etc. when another head won't be particularly expensive?

Just a thought, is it worth considering a change to something slightly more modern, such as a ZRX1100/1200?

Coose

Thanks. I have half of nothing left to spend on the car, all my cash is tied up on sites at the moment.

I've been eyeing up an S Type Jag with a 3 litre V6 and manual box for £1,200! But I think the cost of that + new exhausts + megasquirt is going to be prohibitive.

My email is down at the minute. Could you do me a favour and post the following message on NE7ER's list?

I've decided to do an engine change, today. I've sourced a replacement engine, but need a hand getting it out of the boot and into the engine bay. It's either a 2 man lift, or has anyone got a hoist I can borrow?

Cheers

Mike

Done.

If you do go down the route of replacing the motor with something else in the future, I suggested a ZRX as you may be able to use a lot of your existing bits, such as the prop shaft, exhaust, the majority of the loom etc. so to keep costs down.

Saying that, my 2.5 X-Type is rather good so I can only assume that the 3 litre can only be better (same motor, bigger bore). Is the S-Type RWD?

quote:

---

Originally posted by Coose
Done.

If you do go down the route of replacing the motor with something else in the future, I suggested a ZRX as you may be able to use a lot of your existing bits, such as the prop shaft, exhaust, the majority of the loom etc. so to keep costs down.

Saying that, my 2.5 X-Type is rather good so I can only assume that the 3 litre can only be better (same motor, bigger bore). Is the S-Type RWD?

---

Sorry to hear about your woes Mike.

It's always frustrating when you have a fault that you can't easily (low cost) find the answer

I am unable to help with lifing, poorly back, but ok to help fettling if needed

[Edited on 19/8/09 by petrolhead]

I haven't read all the posts so I appologize if this has already been suggested.

During the bleeding process are you using the bleed screw on the water pump ?

Hi Dave

Yup, bled the awkward one that is on the top casing of the pump, which in my case is halfway down the transmission tunnel.

Now the old engine is out, I'm going to stick it on a pallet and connect the carbs / wiring and cooling system up as simply as possible and see what the score is.

Cheers

Mike

I'd like to see the photos of that experiment