Hi,

This is mostly out of desperation that I am posting this question, despite reading posts on similar symptoms on this website.

On the 23rd of November this year, on my way to work (18 mile journey, mostly motorway), first I had some starting trouble at home. This was probably the first cold morning this year. Then half way up the motorway, my engine management fault LED came up. I drove to a garage, where I have had my MOT done twice and I thought they are ok.

They attached the diagnostics and said it was reading a Temperature Sensor fault code and suggested changing the Engine Temperature sensor. They also showed me that despite the length of my journey, the temperature gauge hadn't moved from minimum at all.

Not knowing much myself, I simply asked if changing the sensor would sort the problem out, and they said yes and I asked them to change it. I paid £60 in total, including parts labour and the use of the diagnostics. The sensor itself was £15.

I drove back home that night and there was no problem, but the next morning, I had the same starting trouble and the engine mgmt fault came back as well. So I drove straight back to them and this time, the guy check the fault codes and said there were some codes in memory which sometimes can cause an old fault to come back and he cleared the codes from the memory. I wasn't convinced, but willing to give it a go.

This time the car lasted a couple more days and then another morning in to work, all the same symptoms came up - starting trouble, temperature gauge at minimum, the engine mgmt light coming up and the mpg was about 5 below normal.

I took the car back again and he said he ought to ask a friend who had worked on VWs which are similar. He then noticed that when I turned the car off, the fan never went off after several minutes of pulling the key out too. So he said it could be the fan switch. So he ordered one in and said he'd replaced it and asked me to try it out. He didn't charge me for anything after the first visit.

Same night on my way home still the temperature gauge was at minimum and the fan stayed on long after switching off the car and pulling the key out. What I suspect is that the fans aren't switching off, which is probably draining the battery and hence the starting trouble. Originally the mechanic said that the temperature sensor not working prevents the initial fuel surge needed on cold mornings for the auto-choke to work.

I have now challenged the mechanics and they are saying unfortunately it is a process of elimination as the codes don't reveal much. They've offered to have the car looked up again and doing a drive test for free, but I don't trust these guys do anything.

Does anyone have any suggestions on what to try and what might be going on here?

Thanks a lot for reading this far!

Mark 2 Octavia? Cooling fans staying on is usually down to water in the fuse box. The fusebox needs removing, taken apart and drying out.

Will move to Octavia 2.

Mark 2 Octavia? Cooling fans staying on is usually down to water in the fuse box. The fusebox needs removing, taken apart and drying out.

Will move to Octavia 2.

Thank you for your reply and moving my post.

Which fuse box do you mean, the one under the bonnet or the one by the dashboard? How does water get in there?

I've had a minor coolant leak for a while now, which I've only been topping up... it goes below minimum once in a couple of months. Could that be related?

Thanks

Yes, I mean the one under the bonnet. Some way down its depth there is a join and that is where the water can usually be found, it can get in through a wrongly fitted cover, or as we most often find through washing the engine bay, but the fan tends to stay on until the battery is flat.

I don't think that the coolant leak could be related to the fusebox. The G12 pink coolant will usually leave pink deposits at the leak source, when changing cam belts we occasionally see that there has been a coolant weep from the water pump.

Unfortunately with todays cars diagnosis of a problem is rarely straight forward, unless it has been encountered before. For example the engine may require to be turned at a minimum speed before the fuel is injected, even this simple requirement will put into the diagnostic equation the battery, starter motor and the means by which the engine speed is measured, add to this combustion chamber preheating, the preheating time and the conditions programmed into the ECU to allow the preheating and you get another level of complication.

You may need to persevere with your current garage or take it to a Skoda dealer, a respected VW specialist or an auto electrician. Where their labour rates may be higher than what you are used to paying, they may take less time to sort the problem.

Thank you fordfan. I persevered with the garage and this time they said the thermostat housing needed replacing as it was broken. This was the first thing the Skoda garage where I bought the car from had advised me. So now, after some haggling on the cost of the repair, I have an original Thermostat housing replaced in the car. For the first time in over a month, the car temperature gauge has shot up to 90 within a few minutes of driving and stayed there. The MPG is back to the original 38-39 region. This morning, the first time in a month, I was able to start the car without any trouble. I am hoping this has indeed rectified the problem. Fingers crossed!

The part costed £77.08 + vat and a seal was needed around £3 + vat.

On a side note, I am not sure mine's an Octavia Mark II! The bluelines were a special editions of the last of the pre-2004 builds.