Ok, I\'m losing coolant.
However, I know where from: the expansion tank. I noticed yesterday morning that I had a nice little puddle under the car: the drips were coming from the expansion tank - so tonight i thought i\'d investigate thinking there might be a crack or something in it. However, i found out that there\'s a hole in the tank to let excess coolant out. Each time i get in the car the coolant buzzer goes off to warn me that it\'s low. I top it up, and lose water from the expansion tank.
My first thought would be overheating, but the temperature on the apexi never goes abover 95. The greddy temperature gauge also never exceeds abnormal temperatures. Starting the car hot and cold is not a problem (In fact, she starts even more easily when the coolant is about 40 degrees than when cold!). So what would peoples diagnosis be? I recently changed my thermostat for a new one because it was sticking. I also have a brand new rad cap and thermostat housing cap. The coolant has not been properly flushed when i changed the thermostat - could i have a build up of gunk in there somewhere causing this?
Sorry - bit of a long one that!
First check the pipe and the two joiners that go to the exp tank from the ast since these can be disturbed and you need a reasonable seal to allow a vacuum to be formed to pull the coolant back when it cools down.
If you do loose water you are more likely to boil the remaining water.
Also do you dump water when the car is first switched off and then the low water buzzer goes when you switch the car back on again?
Water pressure cap are you runnuing - .9?
Just some pointers in the hunt to find the leak
Keith
I lose water when its turned off and then when it\'s turned back on the buzzer sounds (and then i top it back up - so it\'s never been run on low water), and the pressure cap is a 0.9 bar cap. The seal may not have been perfect though.
Coolant system is prone to age-related failures and the symptoms you\'re seeing could be related to issues with ast or some pipeing so the water isn\'t drawn back in to the main system as it cools.
Another reason (and the one I had) was the water being forced out of the expansion tank due to excess pressure from seal failure. I didn\'t see any issues with excessive temps from this, just coolant top-ups every clod-start and eventually poor starting (1-rotor).
Simple thing would be to pressure-test the system as this should highlight leaks. If there\'s a pressure drop but no coolant is found leaking then it\'s internal (i.e. seals).
Hope it\'s a dodgy pipe!
I just spoke to Clive about this, and because I have recently replaced my thermostat it could be down to an air lock. I have been filling the coolant up until it comes out the filler neck and apparently this isn\'t the way to do it as the coolant system will send out more than it needs when it expands. He said i should pour in enough coolant to cover the sensor and that\'s it. So that\'s what i have done, and i shall have to see how it goes!
I will be getting it pressure tested next week. Hopefully it\'ll come back ok! :)