Coolant temp scary low

[Pesky jones]

I.found how to replace the sensors in another thread which looks reasonably simple. Ill try this tomorrow. If it doesnt work then ill research into replacing the stats.

In your very first reply doylebros the how to on replacing the three stats doesnt look TOO complicated, just time consuming. Thanks for all your help, much apreciated.

Tom

[doylebros]

I.found how to replace the sensors in another thread which looks reasonably simple. Ill try this tomorrow. If it doesnt work then ill research into replacing the stats.

In your very first reply doylebros the how to on replacing the three stats doesnt look TOO complicated, just time consuming. Thanks for all your help, much apreciated.

Tom

YouTube has a video of the job on a A3 which is worth a watch for the main thermostat

[doylebros]

This was the video read the comments

https://m.youtube.com/watch?v=nZDMexvOlmU

[Pesky jones]

If I were to replace the two inline stats, and that solved it, would I need to replace the main stat?

[doylebros]

If I were to replace the two inline stats, and that solved it, would I need to replace the main stat?

No and you may be lucky.

[r5gtt]

Good luck with that as mine is on 70k miles and I'm thinking the main block stat may need renewal as it's a time consuming job so bet it's never been replaced. 

M

[PT82]

Mines on 43k and being replaced next week. Expecting three hours labour.

[r5gtt]

Mines on 43k and being replaced next week. Expecting three hours labour.

That's a bummer and it doesn't look straight forward either and there's me thinking the tt mk1 was a pain to do 

Thanks

M

[r5gtt]

Mines 105k :o

I was stupid as I should have bought one with higher miles as it would have cost me half what I paid for this.

M

[Madone]

If I were to replace the two inline stats, and that solved it, would I need to replace the main stat?

Unfortunately is unlikely to be the two inline states, they only speed up the warm up of the engine so (in theory) you get warm air in the cabin and quicker engine up to temp. If the main stat was ok but her inline are bust then you would still run at 90 just take longer to get there. It's the main stat which makes it run cold, it keeps taking cold water from the rad when it shouldn't. My car ran at 70ish and dropped below slighting when cruising, changed the main stat and sits on 90. You can check if it's the main stat. When the engine is at 70 or whatever your running temp is now, have a feel of the rad core, if its hot the stat is open and knackered. Be careful about the fans coming on, they shouldn't but if the temp sensor by the main stat is shot the fans may come in early. you could always unplug the battery to not risk your hands 

[Pesky jones]

Hmm it did actually get to 90 today after ages though.

So you dont think I should get the two stats? It seemed to have worked for others...

I have only asked for.vw to order them in, I dont have to purchase them do I?

[Madone]

If it gets to 90 and stays there then you are good. The line stats stay open once the engine is warm, the main stat regulates by open and closing depending on engine temp to keep it at around 90. You could in fact ditch the inline stats, not saying your should, but the car would just take longer to warm up. The main stat regulates temp once everything is warm and you are driving.

How are you reading the temp ?. If you are using the gauge in the car that's nmissleading, my car always read 90 even when it was 70  , the car gauges read 90 at any temp from around 75 to prob 100 before they move. It's to stop people running back to the dealer as temp fluctuates through normal driving.


You need to read with vagcom or a obd reader to see what is really happening

The main stat is really common, you will find your turbo run on water pump won't run very often either. Loads of people think the pump is duff, when in fact their main stat has gone, car doesn't get to 90, gauge reads 90, ecu doesn't run the over run pump at 70 

[Gmaster]

Mine is also doing this recently (96k) ,got it booked in to an independent next wk he said it's very common .
Cost is gonna be £250- £300 
This car is costing me s small fortune !

[Madone]

If it's making tha gauge move its def the main stat, you will likely find its running at about 70-75. I have a friend who is a master tech at Audi, he does all the work on my car and changed the main stat. He has never changed a single inline stat but many main stats., read into that what you will 

It's not a simple job, it's under the inlet manifold so not a 2 min exercise.

[Madone]

Yes mate, that's exactly it.. The stat is open too early and not closing so the engine is getting over cooled by the rad.

Save your money and time on the inline stats