Hi Guys,

Having topped up my coolant a touch a couple of weeks ago, thinking the exteme cold might be to blame, I've started my car today after not driving since Sunday (when I last checked coolant level) and was greeted by the coolant warning light.

Upon checking the level, it is well below the minimum line (about an inch), so the sensor is doing it's job.

I've checked the upper and lower pipes from the coolant bottle itself and they seem fine. I cannot see any signs of leaks in general in the engine bay.

Where specifically should be checked for signs of leaks please?

Are there any common places, or causes, for this?

I'd really appreciate your help on this, have tried a quick search but didn't find the relevant info.

i had the same problem a couple of weeks ago. Turned out to be the heater matrix. (Cost me £140 for replacement and fitting.)

Feel around the passenger foot well for any greasy dampness.

Crikey I hope its not that then.

I'll have a butchers, thanks for that.

Any other suggestions are more than welcome.

Just checked the passenger footwell, dry as a bone thankfully. Thanks John, that is hopefully the heater matrix out of the run for the cause of the leak.

Please post any other possibilities you can think of.

Many thanks.

I got told that they like to go at the radiator switch, or thermostat? Whatever it is that plugs into the side of the radiator.

Could be the radiator it's self though... Not un heard of.

water pump can cause leaks and all sorts of problems, head gasket failure could also be to blame.

head gasket failure could also be to blame.

That Causes Mayo under the oil cap, though..... right?

I also read something about the inlet/outlet pipe on the bottom of the radiator, That can leak at the joint, a washer or something. Sorry for being so vague, i have a terrible memory.

Thanks everyone for your responses. I've topped the coolant reservoir up and have left the car indoors with some absorbent pads underneath.

If she leaks any more hopefully there'll be some indication as to where from in the morning.

Does anyone know whether there is supposed to be a seal on the underside of the reservoir cap?

It looks like there is a groove for one; I was thinking that the absence of such a seal might cause coolant to vent via the lid, hence low coolant levels.

Just a thought.

Again, please feel free to share your knowledge and experience, I'd like the get to the bottom of this.

Many thanks.

A small leak can develop from the rad temp. switch, which does not have any type of O ring or felt seal fitted. Coolant can dribble down to the bottom hose connector and appear to be leaking around this area. The coolant will leak from the nearside front of the car. It isn't a serious problem and mine only dribbles during hot summers when I've been driving hard, the leak seems to start after 10mins or so after switching the engine off.

They can also leak from the radiator tubes where they join the side of the radiator.

This forum is interesting and I wonder if anyone can help. We have a Skoda Octavia Estate FSI 1.9, bought new in 2005, and a leak started in August 2009 and has progressively and slowly, until recently, increased. It has now increased to the point that I need to top up the water once a week.

The garage has pressure tested the engine - no problem; looked everywhere for the leak - nothing found. The only alternative appears to be an internal leak which would require the engine being stripped down and possible new head gasket. The performance of the car does not appear to be affected, which I would expect if water was mixing with the oil; no sign of creamy streaks in the oil either.

The reason why I am contacting this site is that I have been reliably told that coolant leaks are a problem which Skoda will not admit to - has anyone else heard of this?

Doesn't g12 coolant glow under ultraviolet light?

Could be a way to find it

I think I must've posted the cause of this in another thread.

Anyway, for the benefit of recent posters who might wish to know, it was a hairline crack in the heater matrix. This requires a replacement (£120 for direct Skoda replacement, or about £60 for aftermarket) and a good garage to take the dash out to get to it and replace it. I also had new hoses fitted at the same time.

Hopefully this is not your problem, but if it is expect to part with around £500.

Check my other thread ("Mysterious Coolant Leak", if I recall correctly), as other people posted potential causes of coolant leaks, which could be responsible for your predicament.

Hope you identify and sort it quickly and cheaply anyways.

C.