I'm losing coolant at an alarmingly quick rate. I filled the bottle up Monday and it's just on the level again. I have noticed that the cap seems quite loose. is it possible the cap is knackered and it's evaporating

I'm losing coolant at an alarmingly quick rate. I filled the bottle up Monday and it's just on the level again. I have noticed that the cap seems quite loose. is it possible the cap is knackered and it's evaporating

Expansion tank cap shouldn't be loose, but I would of expected you to see steam, & coolant pouring out if it isn't sealing. Any white smoke from the exhaust? Signs of a leak?

Try and get someone to rev the car and check if you can see any leaks coming form the hoses.You may have a pin size hole thats difficult to see.

If the cap on the expansion bottle isn't sealing properly, you should have all the symptoms of an overheating engine, because the system isn't properly pressurised.

Can't see anything obvious tbh.

I'm sure the cap was quite hard for the last click, where as it does up quite easy now.

Is there any kind of quick test to check it's not the dreaded head gasket

Yeah you can get a dye block test done. Most garages can do it. My mates at City Service Centre in Bedford St just off City Rd can do it for you 02920464677.

I'm losing coolant at an alarmingly quick rate. I filled the bottle up Monday and it's just on the level again. I have noticed that the cap seems quite loose. is it possible the cap is knackered and it's evaporating

What's the temperature guage doing? If you drive hard with the heater off, does it go past 90?

It's difficult to see leaks from the cap, because the cap vents down a pipe (see arrow on pic)

When you turn off the engine, can you hear a hissing noise from the cap? MAKING SURE YOU DON'T SCALD YOURSELF slowly open the pressure cap. Can you hear the pressure being released?

Don't forget to check for leaks in the car as the heater matrix may be leaking.

If you can't find anything, get a block dye test and a pressure test done.

Ring the garage doing the test, so they are ready to do the block test as soon as you come in. You need to drive it hard before it goes is. Sometimes the HG only leaks when engine is hot and driven hard.

When you have the pressure test done, make sure the heater valve is on full heat and remember it won't normally check the pressure cap as that is where they attach the tester.

Cheers guys

Everything looks and sounds normal, I can here the pressure drop when opening the bottle, it still performs as normal, on steam out the back, no immediate signs of any leaks.

I just topped it up with G12 as the tester (squeezy thing lol) said I was little low.

It's pouring down today so probably not the best time to look for water leaks.

We have a winner, right hand side of the block there's a kind of three way pipe assembly which currently has a loss of white residue which has run onto the gearbox.

I'll get a pic up ASAP

At least it's not the head gasket.

Bit big ...... I'll edit it when I get home

That's the coolant temp sensor at the top of the picture isn't it? Could it be that the housing the sensor sits in has cracked?

yeah that the cts, but wot is the white stuff?

My Peugeot 406 died with water loss symptoms when I decided to buy my Octavia. I guess the Skoda diesel works under high pressure like my old HDI. I thought it was a blockage or something, but in the end it was the head gasket. I was told on the modern diesels (like the 406hdi) when the head gasket starts to fail the high pressure forces air from the cylinders into the coolant which was pressurising it and forcing it out of the header tank. I paid £1000 to get the head done and a year later it failed again. Obviously there was something causing it to fail, so I cut my losses and scrapped it. It was the RAC recovery guy that said the best car for me to get next was an Octavia. He said he only had one breakdown recovery a year tops on Octavias. So I took his sound advice and have loved every minute in my Octy. Just an 03 90bhp tdi ambient estate, but brilliant. Especially with my Golf gti seats to keep my comfy!

yeah that the cts, but wot is the white stuff?

It's crystalised G12

Exactly the same symptoms as mine mate, Mine was losing coolant for weeks, finally gave up one morning in a cloud of steam and it was the same pipe thingy that is leaking on yours, it had cracked along the moulding/ casting seam and was only noticable when the engine was hot. Got it changed and it was still losing coolant, had it checked again and it turned out to be the head gasket...... head totally knackered, still in now getting a new head etc...... now there is a problem with the camshaft sensor, replaced that but still flashing up the same fault code and won't start properly..... gutted and fecking expensive, not to mention that I haven't had my own car for weeks now...... fingers crossed yours isn't the same mate.!!!

Found a guide http://uk-mkivs.net/forums/p/155942/1029860.aspx

All sorted .............. I hope lol

Changed the housing and given it a test drive or two

Nothing leaking now but strangly no obvious crack/split in the old housing.

It must be tiny or hidden as there wasn't much dripping out considering the mileage I did last week.

Job made about an hour easier by using a set of spring clip pliers (cable operated clamp type thing) it just whips them of in one easy go.

Thanks for the input gents