Please Help, Going out of my mind

[davegttph1]

Firstly, sorry for the long post, tried to cram everything in that I can think off so your all in the picture.

OK, After being scared sh!tless for a while Ive managed to spend some time looking at my rex. a few weeks back I checked my water and noticed that although the filler neck looked like it was full the AST was short on water (about half full) I knew this needed to be full so I topped it up at the AST and not the filler neck, Im thinking this was my first mistake and maybe created an air lock or something, can anyone confirm this is what would happen, anyway the car has been fine and driven fine for a while. I then started to notice that once a week the car needs to be topped up with a bit of water, not too much but its low enough for the buzzer to alert me. So Ive been doing that whilst on the look out for a water leak. 2 weeks ago I took the motor for a blast 15 miles up the A1 to collect a mate and 15 miles back, the car did get some stick. when I got home I noticed water dripping and it managed to work its way onto the wheel and up the side skirt. Couldnt work out where it was coming from but I was going on holiday so left it there and looked when I got back, since thought it could have been my air con as it had been left on. So Im convinced I dont have an external water leak but it still needs to be topped up every now and then.

Ive come to the conclusion that its either 2 things, the AST water cap or the coolant seals (please god no) Is the airlock forcing water through the AST cap do you think and it just needs a flush out etc? The other reason I thought Coolant seals is the last 2 times Ive used the car it seem/sounds/feels like its started on 1 rotor, a little blip of the throttle and it back on 2 rotors and drives perfectly... Now Ive read up on here about the Champaigne test so guess what I did at dinner time, yup gave that a go.... I even took 2 video clips of it to show you what I did....

Started it from cold (and funnily enough it started perfect and on both rotors with no smoke at all, I have been experiencing alot of blue smoke upon start up but dissapearing within 15 seconds) and at 42 degrees (on the Apexi) this is what it looked like.

http://media.putfile.com/42-Degrees-AVI

So I left it running and when it got too 72 degrees it looked like this

http://media.putfile.com/72-Degrees-avi

Now there was NO SIGNS OF BUBBLES WHAT SO EVER (thats a good thing, right? ) If I revved the car the water would go down, if I kept the revs on the water would go right down back oout of the bottle but as soon as I let off a big bubble came to the top like it burped and it filled back to the level it previously was at....

At 72 degrees I had to turn the engine off because as you can see the bottle was full and still rising. At turn off the water didnt go down. I dropped about 1cm over the course of 10minutes... Obviously leaving it longer I think it would have gone down further but I had to go back to work and couldnt leave the bonnet up....

Sooooo, has anybody got any words of comfort or at very least wisdom? Im a good 2hours+ away from any specialists so Im hoping to get it sorted on my own to start with but if there is a problem I dont want to keep using it and making it worse.

Thanks for reading the essay

[rx7veilside]

if u run the car with filler neck off water will rise as the thermostat has a small hole in it which will let water out..the cooling systems on these cars are a tad strange
take both filler and ast cap off
fill ast and replace cap
fill at filler neck and burp the system using bottom rad hose
run car and repeat as many time as neccy
do not remove ast cap again just regular fill point and syst shd find own level
check for any water leaks
if u are still loosing water get it checked by a pro for peace of mind
airlocks can take a long time to get rid of

[RobbieRX-7]

The first thing that springs to my mind is your expansion tank in the drivers side wing. If leaking it will leak over the wheel.If i were you i would try and burp the system again. Remove the throttle body hose, cut a pop bottle in 2 like you already did, seal this bottle to the filler neck and get a big gush of water/coolant mix to force the air out of the removed hose. As soon as the water pours out the hose, quickly replace it and the system should be bled...worked for me.

[davegttph1]

Robbie, thats the only thing I could think off around that area which would give them symptoms but it only did this when I picked my friend up. Ive since used the car 4 or 5 times and not seen any signs of an external water leak.

RX7Veilside, If I take both caps off and fill the filler neck area the AST water level rises, do I just do that? Or do I fill it directly into the AST? Surely there is a better way of getting rid of an air lock than burping the system, previous experience on other cars have told me there are other "proper" ways like bleed nipples and stuff.

Thanks

[RobbieRX-7]

Also a faulty ast cap can cause too much water to flow into the expansion tank, which overflows and looses all the coolant

[nikp]

IF it is coolant seals, the symptoms you\'ve described will get worse and worse - I\'m speaking from experience :p

Oh, and the symptoms you\'ve described are the same as the ones i had early on - but at this stage as others have said, could be air bubble.

[davegttph1]

Im keeping fingers crossed that its not the coolant purely because I didnt see any signs of Champaigne bubbles...  I want to be able to drive it if it is the seals, at least that way I can get it too a suitable garage before it completely dies on me and parts are re-useable on it. Otherwise its going nowhere because I cant even get it on my drive let alone a trailer truck...lol

[andrewrx7]

AST itself possibly cracking? Under system pressure, you maybe loosing a bit of fluid through a crack. It may be possible for this to run down the overflow pipe heading in the general direction of the drivers side wing? (I assume thats where you saw the water dripping from?).
Replace the ast cap also. As you are no doubt aware, these are known to eventually fail, and not allow fluid back into the engine, as previously mentioned in a post above. Perhaps the cap is only starting to fail, and is borderline whether or not it allows return of coolant back to the engine - in this scenario you\'d sometimes have no obvious fault, but if it did stick, you would end up overflowing the coolant resevoir tank in the drivers wing.
Are you still using the original coolant hoses? If so, how old is the car? Again, general opinion is that these hoses do not last forever, and will eventually start to leak. You maybe starting to see this - in which case, its time to replace the coolant hoses.

[davegttph1]

Thanks for the reply. The AST is aftermarket and all alloy, I am fairly sure there is no crack in it. The cap I do suspect. if I push the spring in with the outter part of the metal rim should the inner part go in with it or should that stay where it is (the centre part... if that makes any sence) Like this :-



The car is a 93/94 L reg. Still using the original hoses, I have felt most of the pipes and they seem solid, all I can think of is its a pin prick hole and it only leaks when on full chat with pressure going through the pipes.

[MillSpeed]

That little thing you\'ve circled is your return valve and yes it should push in witht the rest of the cap. It should also pull out towards you (away from the metal cap) to allow coolant to flow back from the overflow tanks as the engine cools. It doesn\'t sound like your coolant seals are going, if they were there\'d be  white sweet smelling steam coming out of your exhaust and you\'d get a steady stream of combustion gas bubbles rising to the surface in the filler neck with the engine running. I\'d change that AST cap first as last. You might also have a minor leak somewhere, just enough so that you have to top up from time to time. It might not be very obvious at all, since small amounts of leaked coolant will evaporate pretty quickly off a hot engine.

[davegttph1]

OK cool, thats what I like to hear lol I\'ll order an AST cap in a mo then and take it from there. Im not getting any of them symptoms, its just really wierd hearing the engine start on 1 cylinder to begin with, dont think they need to be changed yet but maybe I\'ll give the plugs a change and oil etc drive up to pips, get his diagnosis and probably a tune up or something.

Thanks for the advice so far guys, please feel free to add anymore suggestions

[MillSpeed]

Just a thought, but I noticed you said you\'ve got an after martket AST. I\'ve heard of some people having AST cap seating issues, is there any evidence of leakage around the top of the AST at all?

[Jonathan_F]

There is a bleed on the standard radiator on the top, front left ans look at the engine. Its a tiny little plastic peg. 5mm A/F or smaller. Mine snapped off when I tried to undo it (gently) and I drilled and tapped the plastic and fitted a M6 cap head. It makes filling the system very easy. I undo the top hose to the throttle bodies at the same time. I would check that the thermostat is working properly as well (boil it in a saucepan. Should be open before boiling point). Sounds like you may be running hot at times. Thermostat could be failing early. Make sure you have a good 50% mix of antifreeze as well (raises the boiling point about 10°C). I had leaks from fainling water pipes that only happened when I seriously cained the car..looking back I think it was the water seals.
Jon

[davegttph1]

Millspeed, I checked the cap before and thought aha its coming from there but then I remembered Id only just topped it up so thats probably why it was wet, I dried it off whenI did the champaigne test and couldnt notice any leakage.

Jonathan, Ive not had the car running hot although I do run the car constantly with the Air Con on once I hit 84 degrees, I dont like it going over 90degrees and my fans dont come on til quite high so thats why I run the air con. Where is the stat? top hose I presume? I also just run 100% coolant and antifreeze (the stuff for £15 from Halfords for 5litres) Dont put water in it unless Im stuck at work and it wants topping up which I only did once. Think theres a chance like you say that its a small pin prick hole in a hose that only leaks on high revs... Still intrigued as to why it was starting on 1 cylinder the last 2 times I used it but started perfectly fine on the test I did at lunch, flooding in one rotor perhaps?

[davegttph1]

Update.... I ran the car at the weekend and got 15miles up the road noticing my temps had hit about 94degrees (driving constantly at 90mph though on Sunday which was very hot so could explain the temp) so I pulled over into a layby and checked it out, leaking again quite alot of coolant it lost what looked like alot, so I turned around and got home (about a 10mile journey) without it going over 94 degrees, if I drove at 70mph it dropped to about 91 and as I got near home on the 30 stretch it actually got down to 89, so I am presuming it was to do with the hot weather... although when I pulled up outside the house I noticed I had left a trail of coolant in the cul de sac where I turned around slowly and where I parked up a puddle was starting to appear fairly quickly, IMO I had lost a fair bit of water, but the car didnt over heat.

Now I did notice the cap on the AST was wet round the rim. although the water dripping on the floor was by the drivers wheel.... I understand there is an overflow tank there though so is it possible I had too much coolant in the system or is it definately AST cap related. The reason I ask is I let it cool down on Sunday whilst going out in a different car to Thorsby show. Today is the first day Ive had chance to look at it and noticed it hardly needed any water what so ever to top it up, (1/4 of a litre MAX) so whats the crack. totally confused by all this now.

Thanks