Coolant leak. Help!

[Sparkie]

Hi everyone, it's been ages since I've had time to post. Now urgent I pick your brains again.
My car is loosing coolant and I can't find a split hose anywhere. Strange as I'm losing a whole expansion bottle within 15 miles yet no sign of leaks at all.
The only thing I found was an oil breather pipe which has split in half. ( new one arrives tomorrow.)
Any pointers as to where I should look next or how to test for a leak would be really handy right now as I can't get to work so it's becoming an issue.
Thanks guys. Olly

 

[hombre_paulo]

Have a look at the coolant sensor housing on the engine block just above the gearbox - give away sign is pink/white crusty stuff near or on it

 

[frijj]

Maybe have a look around the thermostat housing area also.
I had my thermostat changed by a garage and they didn't fit it properly.
When I drove back home there was a massive puddle under the car, I couldn't see where the leak was from the top of the car to determine it myself, but back at the garage and looking from underneath was pretty clear that the thermostat was miss aligned and leaking profusely.
Just food for thought.

 

[addavis89]

Heater matrix?

 

[Sparkie]

Thanks guys.
Thermostat housing was the offending article.
It was covered in crud from the broken oil breather pipe so hard to find. (Seat have redesigned the breather pipe with brass inserts to prevent splitting. And now charge 55 quid!)
Off to German and Swedish now for a new housing.

 

[welo78]

It could be the head gasket - worst scenario or water pump - best case scenario since you do not have any leaks. I would recommend taking off the under tray and leaving the engine for night if there will be a puddle under neath. If there is you are lucky, if there is not and the coolant only drops about 1 cm ... i have bad news