Fault thermostat

**A4donkey** · 09-23-2008 09:00 PM

Driving the car over 30min temp gauge still sitting at the first notch, changed coolant sensor still the same.

Can anybody tell me how to diagnose a fail thermostat?

I am thinking if the fault thermostat stuck open and thinking of doing a DIY replacement according to this.
http://euroautoforums.com/forums/ind...?showtopic=143

Anybody ever done that before, will I need to vagcom reset anything after the replacement of thermostat?
Any tricky procedures should I pay attention?
And how long does it take?

**Matt Devo** · 09-23-2008 10:14 PM

nice of those guys to steal my writeup and pics, LOL.

your symptoms, coupled with having already changed the CTS, indicate that your thermostat is indeed stuck open.

No extra steps need to be taken outside or replacing the faulty unit. Follow my writeup and you'll be all set. Expect it to take 1.5-2hrs

Tech Article

**A4donkey** · 09-24-2008 04:18 AM

Matt , glad you are in this forum, just want to say thank you for your great sharing .
Good writeup man .

Before this DIY, I changed a new battery which I guess the voltage may have done something with the gauge but I am wrong

.

By the way, how many litre of coolant or g12 is needed?

**FourRings80** · 09-24-2008 06:20 AM

Originally Posted by A4donkey

By the way, how many litre of coolant or g12 is needed?

7 liters of coolant are required. So about 3.5liter of G12 and 3.5 liters of distilled water if you go with a 50/50 ratio.

Let me know if you need a thermostat, I'm selling a brand new one in the classifieds. How does $60 shipped sounds?

http://www.audizine.com/classifieds/...ct=1276&cat=21

**A4donkey** · 09-24-2008 06:50 AM

Heard somebody said to diagnose a thermostat physically by feeling the upper and lower pipe temperature, anyone knows how?

**dougyfresh** · 09-24-2008 08:06 AM

Originally Posted by FourRings80

7 liters of coolant are required. So about 3.5liter of G12 and 3.5 liters of distilled water if you go with a 50/50 ratio.

Let me know if you need a thermostat, I'm selling a brand new one in the classifieds. How does $60 shipped sounds?

http://www.audizine.com/classifieds/...ct=1276&cat=21

Hmm. I may want that thermostat.

Obviously the OP has first dibs since he needs it asap and I'm just interested in having an extra one in my 'box of parts'.

**A4donkey** · 09-25-2008 07:27 AM

Working in the dark car park with useless tourch, did not take out the belly pan with some dropping tools

, it took me 3.5 hrs to replace that thermostat.
Yes, my guess is right, it stucks open, the stock one is version G and I put in a version K.
Again thanks for Matt's writeup, without it, I wouldn't do it.

Time to have a beer.