306 HDI coolant leak

glynn · Post by **glynn** » 14 Feb 2010, 14:24

Hi guys.

Whilst driving home from work Friday night the coolant light illuminated on the dash. Managed to get it home without overheating. Checked yesterday and it appeared that the header tank was low so filled it up to max mark, there didn't appear to be any leaks on my driveway and so i set off back to work. less than a mile into my journey the light came on again, faulty connection on the wiring i thought so took it steady to work and on arriving there took header tank cap off, no pressure at all which i thought rather odd and the coolant i'd put in had disappeared. Checked for any water in oil and that is clear also no white gunk anywhere. Anyway i topped it up again and checked it prior to leaving work, all was fine again and again no leaks under car. 2 minutes into journey and blasted light is on dash again so limped it home and left it on driveway again for night.

This morning i have come out to it and as i need it for work, opened header tank and low and behold no coolant, now i know that electrics are fine and reading on dash is working fine as it should. So to test i filled up header with water and as soon as i did i could hear water trickling, i have checked pipes to radiator which are fine, then the water started leaking onto driveway and within a minute or so the header was empty again. the leak appears to be coming from the back of the engine but i don't have a clue where from.

Help please. Thanks, Glynn

glynn · Post by **glynn** » 14 Feb 2010, 14:26

sorry forgot to add, car has done 80000 miles and is on an X plate and has been serviced regularly.

TopDonkey · Post by **TopDonkey** » 14 Feb 2010, 14:55

Theres a coolant pipe that goes across the back of the engine to the coolant manifold that is bolted to the side of the block above the gearbox and the only thing that seals it is a rubber o-ring, if you top up the water and shine a torch up from underneath, see if you can see if it is this o-ring that has gone ?

Post by **myglaren** » 14 Feb 2010, 16:51

Look also for a split seam in the header tank, you will probably need to remove the tank to see it.

glynn · Post by **glynn** » 15 Feb 2010, 18:06

well i couldn't find the leak so got RAC out and after stripping a few bits away he eventually found that the plastic housing which surrounds the thermostat had cracked.

Don't have the time to do job myself this week so its in the mates garage getting sorted, i'll keep my fingers crossed that it hasn't done any other damage to the engine.