Golf V5 coolant gone missing !

[bigdods]

Heres one thats got the garage stumped so any clues would be appreciated..

Drove about 400 miles in a day at high speed, engine running at normal temp, no problems. Went to start the car next morning computer yelled STOP. Checked under the bonnet and the coolant header was totally empty. Checked it the week before and it was up to max. Had no obvious leaks, no steam or nasty smells and no white exhaust. Took it to the garage (having topped it up to max) but they couldnt find any evidence of a leak, no residue, fluid or anything. No gaskets dripping , no scum in the oil filler etc so not a leaky head gasket. Good news - no charge . Bad news - it might happen again.

Help !

[angrys3owner]

umm...

don't wish to worry, sounds like the only way out was the exhaust to me, so something engine internal related perhaps? just a guess mind.

do you trust the garage that inspected it?

[bigdods]

How much do I trust the Garage - well its a VW main dealer so not much really *sigh* . I thought the same that maybe theres a gasket blown out but there is no steam out the exhaust, no sludge in the oil and I ran it for 30 miles today at full pelt and nothing - header is still full. Total mystery to me - but the warranty runs out in about 5 weeks so if there is something wrong I want to find it now .....

I will just have to keep monitoring it and carry water in the car until It shows itself again

[deltafox]

Get it block tested to check for CO in the coolant.....

[bigdods]

Sounds like a good idea, I have a local garage who should be able to do the CO test for me (or at least point me to someone who can). At least if it shows clean then I know what it isnt. Also read somewhere else that it might be a cracked heat exchanger in the car heater matrix - so tomorrow first thing to do is crank the heater up to max and see if I get any fogging and fluid loss.

I will post the results in the next few days.

Cheers

>> Edited by bigdods on Tuesday 31st May 22:31

[kevinday]

Simplest way to check is to pressurise the system and monitor the pressure over a half hour or so. No loss of pressure should mean no leak, loss of pressure means there is a leak somewhere. Check with your garage to see if they did this, I think they probably did not.

[bigdods]

Thanks for all the help, good ammo to go back to the garage with now. On hols for a few days but then I will be back to the garage...I will post the outcome