I knew that would make a nice topic title

So, the Octy has been sat outside the house all day today. It has been cold, in fact it's felt like the coolest day of the winter so far.

Had to pop out, and when I got to the car there was ice on the windscreens, although the dash was deporting 2oC. Started the car up and a few seconds later I get the message as per the topic.

Temperature gauge wasn't climbing any further than the lowest mark (50oC if I remember). Let the car idle for a while and then switched off. Gave it a second, restarted the car, no lights of "dings" this time and eventually the temperature started to raise.

 

My diagnostics:

 

There isn't enough anti-freeze here, so I've managed to get frozen coolant hence the warning message, hence the temperature staying so low, hence eventually the cooling system warning up, fluid starting to move around, no more warning lights and temperatures starting to climb.

I actually had it happen similarly a couple of times last year but those were on bitterly cold days (dash showing something like -7oC on some mornings).

 

So, question 1. How easy is it actually getting fluid out of the cooling system so that I can add some more anti-freeze? Looking this evening with a torch and I'm seeing the coolant at "max" so just adding some in is not going to be a good idea. So how do I get any fluid out so I can add more?

Question 2. I know what I did wasn't ideal, but it worked as it has worked in the past. The cooling system is a pretty much enclosed system, so I'm guessing that any frozen areas of fluid will have warned up and allowed movement throughout. Whilst stationary there would have still be soon coolant in the right places until it "melted" so I'm "probably" not doing any major harm by letting the engine idle until the system sorts itself out. True or false?

 

Cheers all.

I would put my money on the problem being the coolant level sensor in the coolant header bottle misbehaving. I had the problem on my Mk 1 Octavia I and Mk 1 Fabia vRS. See the thread below. which is one of many posted over the years. In the meantime stop worrying about the coolant having frozen!

http://www.briskoda.net/forums/topic/113626-red-coolant-warning-light-beep-beep-beep/

I would not be looking at the coolant/antifreeze, unless you have been regularly topping up with just water!

As DGW has posted look at the sensor.

And leaving a car idling for 5/10 mins will not warm up the coolant very much, you need to drive the car and get it up to temperature, it can take a few miles to get any heat into it. The thermostat will not open until a sensible temp somewhere around 80 degs ( not sure of actual).

Regards

I gave my local dealer a call this morning and they assured me that the antifreeze levels are checked in the system whenever the car comes in for servicing. Skoda say that all vehicles should be good up to a minimum of -25oC so they too started pointing a finger at the sensor rather than the coolant itself.
I'm taking it on Wednesday next week where they will check the antifreeze levels and if sensor is the issue apparently that is a complete bottle change, so they will need to order in etc. Pleased all these little issues are appearing while I'm still in warranty.

The coolant is showing just below max and I've never had the need in the 2.5 years or so I've had it to top it up.

 

Ta

If there is water in the expansion tank and you're still getting the low coolant warning it's probably the sensor.

 

If you open the top of the expansion tank (when cold ) and have a peer in there are a couple of metal prongs that make up the sensor. they can get a bit of deposit on them that gives a false signal to the car's brain.

 

Get a long screwdriver and give them a bit of a scrape and see if that sorts the problems.

 

Very common on the colder mornings to see this.

 

If that doesn't help then you can investigate further.

Mine does this and it's the sensor, As Aspman says give the prongs a scrape.

Just for completion (in case somebody finds it via the search engines etc.)
Took the car in this morning. They confirmed that antifreeze levels were absolutely fine.

They replaced the expansion tank (or part of it) which includes the sensor. All done under warranty and they tell me it won't happen again.

Thank you for posting feedback. Now get on and enjoy your car.