Temperature gauge fluctuates from 70-90, thermostat?

[Gti_Mad]

any1 got the part number for the main stat ??

Probably need to check with main dealer as there are two varieties. One is just the thermostat and the other is the complete housing with the thermostat enclosed.

Mines a 05 AXX an need full housing which was part number:
06F 121 111 F @ £33.91 from local dealers

thanks varley ill pop dwn there 2moz n find out

[doylebros]

That's correct for both BWA - BPY engines

That's the link to the online parts catalogue:-

http://www.partscats.info/volkswagen/en/?i=cat_vag_models&brand=vw&number=1714&set=1731&ein=2008&f=625&hauptgr=1234567890&hg=1&grf=012175420&bf=12175&hgug=121&ug=21&parent_id=2850753&detail_id=2850756

Price quoted is still current and is full retail inc vat.

[CarlW]

I have a question that one of you wizards may be able to answer...

My temp gauge was fluctuating, well more like dropping rather than fluctuating but anyway.. as I was saying.. I've never known it drop whilst driving.. It's only when I put my heaters on and I only put them on when the car is at 12 o'clock on the temp gauge. Now as soon as I knock my heaters off, it climbs back up to 90 again.

I should also mention that I've had a main stat fitted thinking that this was the problem but the problem still remains.

I know there is other culprits to look at such as inline thermostat, coolant temp sensor, coolant temp sender? I think it's called and then the dreaded water pump which if it helps.. This was replaced the same time as belts etc 5-6K miles ago..

I don't want to just have bits replaced for the sake of it but I don't have a clue what the next best thing to do is..

Cheers,
Carl.

[doylebros]

If that was my problem  (since you've replaced the main Stat) I would
Check for an air lock
Check the cap seal
Replace the in line regulator (x2 if it's a DSG)

Then if that fails do testes with VCDS ( the senors I've had problem tend to fail so I wouldn't expect your type of fault with a sensor but testes with a multi meter would confirm if the sensor is in spec)

[col]

I've recently had the main stat replaced and temperatures now reach 90 and stay constant, however it does seem to take longer than it should to reach the correct running temp. 
With regards to the above post,  how would I check for any air lock? If there is one,  how would I remove it?

Thanks hopefully in advance :)

[homesqueeze]

^^^^^ Testes 

[Bo!]

I have a BWA engined GTI seems to have problem ,the temp gauge does reach 90 but when it does it can fluctuate when driving between 70/90.
when driving to work however 4-/5 miles it rarely reaches 90 more like 70 .
I purchased the car from VW 10 months ago and I still have some warranty left would this be covered if I needed a thermostat etc .

[SCILLYBOY]

I have changed the main stat and both sensors and still it goes up and down zero ...to the top warning light comes on no over heating to coolant loss changed water pump even put a radiator flush in