coolant loss

[corradovr6]

my mk5 has a weird issue.

runs for 1000 of miles without loss of coolant.

parked on the flat no loss- parked on a steep bank- looses coolant overnight?

[LC5F]

Does it keep doing this or is it a one off? - one off would suggest trapped air has worked its way out

[corradovr6]

its a contrant thing- park it on a hill either up or downward facing and loses loads of coolant

[muff1991]

ive got a coolant leak on mine, sometimes it leaks, sometimes it doesn't! i think its the thermostat housing under the inlet. Only does it now and then too, i'm certain its to do with the outside temps causing something like the housing to expand or contract. i'll get round to sorting it when the weather gets better!

somethings clearly leaking when the cars tilted... try and locate the leak if you can. take it for a good heavy footed drive come back and park on your hill, listen for pressurized hissing and look for coolant dribbling.

[ROH ECHT]

Could also be the pump...ffwd to 2:10;

...and the coolant bottle...ffwd to 3:50;

...but yeah, going to require getting it to operating temps, park it as you do when it loses coolant, and go inspect it thoroughly about 30 minutes later.

[corradovr6]

weird thing is that it loses no coolant when hot and in normal driving conditions.

When its parked on a hill it has been when ive parked it on a slope on my drive when going away and the cars cold as I only moved it a few yards.

Obviously I don't park it there anymore but still the issue is there and it definitely happens when cold.

To be honest - all of my drive slopes and its ok on the less steep part of the slope, its only the part with a steeper slope that gets the coolant leak?

[ROH ECHT]

I feel the expansion tank has a leak. This will cause levels to go up more than normal. When it is parked the level may go up a bit before it cools and begins to drop. That may be causing fluid to reach the point where the leak is and exiting the tank.

The other possibility is its pressure relief on the tank. Sometimes when fluid leaks from it, the problem is the cap seal is shot. This allows more pressure inside the tank when the cap no longer seals and just a new cap is needed. But the relief itself can fail and that means a new tank.

[corradovr6]

cheers.

I have changed the cap- but maybe the seal is to blame.

But this happens when cold so I suppose the levels would be at their lowest point.

When I say it loses coolant I mean big time, around 1.5 litres

[muff1991]

mine also loses when cold as mentioned above, i think its a temp thing to do with expansion and contracting. i think the area of my leak expands when hot and closes the gap then when cold it contracts and coolant starts to leak!

you need to work out roughly where the coolant is coming from. i dont think pressure is your problem i think contracting when cold is your issue.. locate the leak.

if you dont have one, you can buy a coolant pressure tester for around £40 on ebay or pay a garage to find the leak with theirs.

[corradovr6]

that makes sense- I will see if I can get hold of one.

at the moment I am just making sure I don't park it on a big hill