Topping up with water.
Discussion
Not sure if this is a dumb question but I was doing a long trip this weekend so I wanted to make sure I had filled up with water before the run down. I topped up to about an inch short of the top and about 3 minutes later there was a healthy dribble and small puddle being created in front of the car. This also happened about 6 weeks ago. I am pretty certain there isn't a leak but is there some sort of overflow or should I just not fill it so high ? Any comments welcome as you can probably guess, my middle name is not 'technical'.
The correct level for coolant is midway up the expansion tank (the one on the inner wing).
If the coolant has been drained for whatever reason, air may have got into the system.
To check,from cold, undo the brass screw on the swirl pot and then remove the radiator bleed plug (at the top of the rad nearest to the offside inner wing).
When no air bubbles can be seen in the coolant escaping, replace the plug.Make sure you keep the swirl pot topped up while doing this, and then fill the swirl pot to the top and replace the plug.
Finally make sure the coolant level is up to the midway point in the expansion tank.Replace the blue plastic pressure cap.
If the coolant has been drained for whatever reason, air may have got into the system.
To check,from cold, undo the brass screw on the swirl pot and then remove the radiator bleed plug (at the top of the rad nearest to the offside inner wing).
When no air bubbles can be seen in the coolant escaping, replace the plug.Make sure you keep the swirl pot topped up while doing this, and then fill the swirl pot to the top and replace the plug.
Finally make sure the coolant level is up to the midway point in the expansion tank.Replace the blue plastic pressure cap.
My old man taught me...
Remove the cap, header screw and radiator plug and fill everything. Now close the header tank and put the plug in the radiator, not too tight tho
Start the engine from cold. At this stage the thermostat prevents water from circulating until it is up to temperature. The water will creep up the expansion tank as things start to heat up and the coolant will start to flow out the expansion tank, in a controlled, dribbly overflow type manner I hasten to add, anything else and well...
Eventually once the circulation system starts proper, the level in the expansion tank will drop fairly quickly, keep putting more coolant in at this stage to prevent any air getting in. Once it starts to settle out fill it to the half full mark and put the cap on. Tighten the radiator bleed bolt (if the radiator was full some coolant should have leaked out when it wasn't fully tight.
Once the car has cooled down, open the expansion tank and check the level, it should've dropped but not be empty. Top up to halfway.
Seem to work pretty well... And remember coolant is a bit like blood, a little bit of it spilt looks like gallons when you're paranoid about it
I think the key thing is that because the water circuit is not 'open' until the engine is up and running it is fruitless to try and persuade it to take coolant esp thru the expansion tank which isn't connected to much of the circuit at that point
I was completely oblivious to this but once you watch it in action it all makes sense
>> Edited by prussianblue450 on Monday 12th July 21:07
Remove the cap, header screw and radiator plug and fill everything. Now close the header tank and put the plug in the radiator, not too tight tho
Start the engine from cold. At this stage the thermostat prevents water from circulating until it is up to temperature. The water will creep up the expansion tank as things start to heat up and the coolant will start to flow out the expansion tank, in a controlled, dribbly overflow type manner I hasten to add, anything else and well...
Eventually once the circulation system starts proper, the level in the expansion tank will drop fairly quickly, keep putting more coolant in at this stage to prevent any air getting in. Once it starts to settle out fill it to the half full mark and put the cap on. Tighten the radiator bleed bolt (if the radiator was full some coolant should have leaked out when it wasn't fully tight.
Once the car has cooled down, open the expansion tank and check the level, it should've dropped but not be empty. Top up to halfway.
Seem to work pretty well... And remember coolant is a bit like blood, a little bit of it spilt looks like gallons when you're paranoid about it
I think the key thing is that because the water circuit is not 'open' until the engine is up and running it is fruitless to try and persuade it to take coolant esp thru the expansion tank which isn't connected to much of the circuit at that point
I was completely oblivious to this but once you watch it in action it all makes sense
>> Edited by prussianblue450 on Monday 12th July 21:07
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