Hmmm..was driving to work minding my own business this morning, when I looked down at the dashboard and saw that the temperature gauge was reading somewhere around 70 degrees, when for the last 5 years once the engine was warm it has always sat squarely on 90 degrees (i.e. vertical).:confused:

This evening, it has moved between 75ish and 90, depending on speed (and therefore cooling effect of air I imagine, being non-technical). It has never fluctuated at all in the past (not while I've been looking anyway). I did a short run a while later, while the engine was still warm and it sat on 90 the whole time.I saw this once in a Ford Mondeo I had, which ran cool all the time until I replaced the thermostat and discovered that the heating DID work!

Has anyone else seen this, and is it the thermostat misbehaving, or something more sinister?? It's due a service imminently, but I'd like to have a bit of an idea what's occurring.

Thanks,

HH

I would think its a temp sensor.

I would think its a temp sensor.

Yes - I sat and watched the temperature gauge fluctuating while the car was stationary last night, but today it has behaved exactly as normal. Will just have to keep an eye on it and mention it when it goes in for service. Thanks for the tip in any case!

mine was pretty much the same it was the sensor playing up had it changed

sorted

mine was pretty much the same it was the sensor playing up had it changed

sorted

Was it expensive? :confused:

tbh it was warranty work but i don't think they cost that much

try this link its on there but it an 04 price list

http://www.briskoda.net/forums/octavia/octavia-useful-part-numbers-octavia-diy-servicing-mods/55981/

Had a similar issue with my last car (VW Golf). Dealer's first thought was sensor, then they checked the thermostat, by which time the gauge would read either zero or max. Turned out to be a disintegrating water pump impeller, plastic crap which costs little to produce but could have caused major damage if left untended, and necessitated major work (and cost) to replace. Hope your problem is the cheap option!

Had a similar issue with my last car (VW Golf). Dealer's first thought was sensor, then they checked the thermostat, by which time the gauge would read either zero or max. Turned out to be a disintegrating water pump impeller, plastic crap which costs little to produce but could have caused major damage if left untended, and necessitated major work (and cost) to replace. Hope your problem is the cheap option!

I had almost identical issue with my old Octavia RS. On a journey in very cold weather, I had been sat in a line of traffic at 40mph, and when I got onto dual carriageway and upped speed to 70, a dash alarm went off and I saw the temp needle fly into the red. I pulled over immediately, and called breakdown service. Turned out the thermostat had failed leaving the water pump to burn itself out.

In a seperate incident, I did have to replace engine temp sender, and expansion bottle coolant level sensor.

If it's a sensor will it register a fault that the dealer can pick up? I don't like the sound of the water pump, having already had a cambelt disaster this year:eek: - a sensor must be much cheaper than either of the other options!

Dealer couldn't seem to identify the cause from the effect, or by diagnostics, so they tackled the obvious (& cheapest) solution first. Whether the dealer knowledge was crap, or the diagnostics tool, who knows? But better to get it fixed than have an engine seizure!