Towards the end of the summer I had the old sticky thermostat problem causing the engine to overcool when off gas.  Got the stat replaced and they did temp sensor while they were there.  Problem solved (at the time).  However, recently since the colder weather the engine temp has dropped slightly on my way in to town.  There is a long downhill, straight section where I'm off gas for a good while and the engine has only just reached peak temp before I'm at the top, as I get to the level ground temp has dropped just below 90.  Question is, given the car has only just reached optimum temp, is this down to the colder air entering the bay and therefore considered normal with being off gas for so long, or is it symptomatic of a non VAG thermostat playing up?  I've owned a few VAG cars before and the gauge has never budged off 90 when it gets there, but then these circumstances are fairly exceptional.  It is the only time it does it and nowhere near as bad as when it was sticking, as then the temp would drop after being off gas for only a few seconds, and would drop alot more.

far as I remember once engine is heated up the sensor will always keep it on the 90 mark, even tho the engine might run hotter or colder, I also know that cheap replacement sensors usually cause more hassle than worth.. as most of the guys on here say buy cheap buy twice lol...

so if it was a cheap one likes off ebay it might be worth buying a genuine one and see how that goes

far as I remember once engine is heated up the sensor will always keep it on the 90 mark, even tho the engine might run hotter or colder, I also know that cheap replacement sensors usually cause more hassle than worth.. as most of the guys on here say buy cheap buy twice lol...

so if it was a cheap one likes off ebay it might be worth buying a genuine one and see how that goes

 

It wasn't an ebay one but pretty sure it was non VAG through my local garage who fitted it, is it likely it is just the stat, or sensor, or both do you think?

I had garage do mine other year and they used a cheapo lasted a wee while but had same problem and swapped it over for a genuine one, I would start with that as it the cheaper option, I found if the temp goes up and down it most likely the sensor....

Cool, do you have a part number for the sensor?  Had a quick look through the list on here but can't see it.

This one:

 

http://www.skodaparts.com/product/octavia-coolant-temp-sender-sender-1997-2008-27656

 

And this one?

 

http://www.skodaparts.com/product/octavia-thermostat-1-6-1-8-2-0-1997-2008-27500

Sounds more like the stat but could be either & get genuine as my pattern thermostat failed too...lesson learnt.

http://www.briskoda.net/forums/topic/244609-how-to-replace-coolant-temperature-sensor/

 

I followed this guide....

Sounds more like the stat but could be either & get genuine as my pattern thermostat failed too...lesson learnt.

 

Indeed, is it those parts listed above?

Looks a-ok, need an O ring for the thermostat too

Looks a-ok, need an O ring for the thermostat too

 

Sweet, I've ordered both, with O rings, cheers dude.  Has burnt a bit of a hole in the wallet but hey ho, such is life

Fit them yourself and save a few quid then

I may give the stat a bash, sensor for definite. Main problem is I have to work outside, not a pleasant experience at the moment.

Its warmed up hasnt it?  For the thermostat its fiddly, need some long quarter inch drive bars and elbow and allen bit

Its warmed up hasnt it?  For the thermostat its fiddly, need some long quarter inch drive bars and elbow and allen bit

Haha yeah, sort of, bloody windy and wet though which is worse for me, don't mind the cold as long as it's dry. But yeah I've checked a few how tos and would need a couple of tools by the looks of it...not a fan of fiddly jobs mind.

Is changing the thermostat an easy job? Need to change mine

Is changing the thermostat an easy job? Need to change mine

If you Google 'replace thermostat 1.8t' a few how tos pop up for Golfs and the like with same layout. Saw one guy take off throttle body and alternator, another who didn't. It looks as though the pitfalls are breaking the brittle dipstick tube, and an awkward bolt on the thermostat, hence the need for an elbow on the socket. It looks fairly straightforward, I'm just not sure I want to tackle it in this weather. Not sure when I'll get chance and don't want it dragging on, my cars in for MOT on weds so hopefully it will arrive by then and I'll get them to stick it in for me.

With the right tools you dont need to remove big parts such as the throttle body or alternator, you need some cheap quarter inch extension bars, an elbow and an allen socket