Coolant...all over the place.

[selmer]

Went for a drive this evening and after coming down main road into strong, cold headwind I pulled into back alley to put car in garage. It was running at a nice temp on the road but obviously warmed up when stationary (emptying boot, looking for garage keys etc). About 10 minutes after leaving garage I returned briefly to get something only to find approx 1/2 to 3/4 of a pint of coolant on the floor dripping from the front of the car. I've only just come in and haven't consulted 'the bible' yet, but I've checked for loose clips and have tried to have a look to see where it's coming from (hard in the dark with a small maglite). It looks like the radiator isn't the culprit but I have heard that if the motor runs hot then some coolant can be 'dumped' through an overflow. I'll have alook tomorrow after work and see if I can find something amiss but in the meantime do any of you know what may be the most possible explanations.
Thanks, Tony.

[arcturus]

My 350i does exactly that. Vents coolant through the overflow when hot. I've stopped worrying now I know what it is.

[Gerry Attrick]

arcturus said:

My 350i does exactly that. Vents coolant through the overflow when hot. I've stopped worrying now I know what it is.

It should only do this to expell extra coolant, and not all the time. If you've recently topped her up this could be the problem though.


>> Edited by Gerry Attrick on Tuesday 5th October 08:53

[GreenV8S]

Pressure goes up with temperature, if the pressure cap is knackered it might seal OK until the engine gets hot. (Same is true of leaky radiators, hoses etc.)

[2 sheds]

It's worth giving the system a pressure test, if you can borrow a testing kit from a mechanic, you'll be supprised at how many small leaks that can appear.
Tim

[350zwelgje]

Had the same problem: source was the connection just below the coolant filler cap (new hose clip did the job). And the filler cap can be a source as well....
You could do a search, topic has been discussed before.

Rob

[selmer]

Thanks chaps. didn't do it this afternoon (same circumstances too).
It isn't the filler cap as there is no sign of moisture around or beneath it. Hope it was just the heat induced 'dump'.

[adam quantrill]

I take the overflow off mine and stuff a 2-pint bottle behind the
expansion tank and run the overflow into it.

This way you can keep an eye on any expelled fluid even
if it happens on the move.

Another advantage is that you can return the coolant to the system
and if you're as tight as I am that's reason enough!!!

- Adam

[arcturus]

Gerry Attrick said:

It should only do this to expell extra coolant,

Indeed it only does it if I have topped the coolant up to the top of the indicator in the expansion tank. If I leave it so that the bottom of the expansion tank is just wet when cold, then it does not vent fluid at all when hot.

[DJC1001]

selmer said:

It isn't the filler cap as there is no sign of moisture around or beneath it. Hope it was just the heat induced 'dump'.

Doesn't quite figure - coolant has to lift the the cap seal to excape via the overflow pipe.
Check the expansion bottle cap is 15psi.

Some cars have an overflow bottle after the expansion tank. If the overflow pipe is sealed at the expansion end and below coolant level in the overflow bottle it should return dumped coolant back to the expansion tank as the system cools.

David