RussAdams

This is a great write-up!

The photos are still on the site, just in a different directory. Below I've re-linked all of the original photos. These are RafaTT's photos, not mine. If I linked to the wrong images, I apologise in advance! RafaTT's original photo's are located here: https://www.audiworld.com/g/album/1101234

RafaTT's original post, with photos:

Well, here it is: I'm not going to say it is simple, but it actualy is. All the procedure should take 15 to 30 minutes,
Here are the tools you will need to do this: 3/8" ratchet, as many extensions as you can get (about 24"), a 10mm short socket, 10mm box end (or long socket), flex joint , 5mm allen wrench or socket, a magnetic pickup (or needle nose pliers) and a channelock.

We will asume the engine covers are removed, NEGATIVE post of the battery removed (check radio code first!) and of course, car IS cool, no radiator pressure. Also, a clean engine bay will help a lot.

Start removing the following screws:


pull the tray up to release the hook for the oil dipstick and then separate from the manifold about 2 inches. Remove the connector on your left


put the whole assembly to the right and hold it is place (I use a ty-rap for this)


Here is the first "catch", the oil dipstick tube gets very (I mean very) brittle after a couple of years, so as it has to be removed for clearance, it may break so will need to be replaced. Be careful that when it breakes it leaves a little piece or plastic (orange)tube inside the metal part that goes to the oil pan. This has to be removed too, use an old flat screw driver with a bent tip to pull this piece. This looks like this:


<img src="http://pictureposter.audiworld.com/62820/p6300029.jpg">

Pull the orange tube up, it will do a little snap and release like this:


<img src="http://pictureposter.audiworld.com/62820/p6300005.jpg">


Now we can see where are we going: here!


<img src="http://pictureposter.audiworld.com/62820/p6300006.jpg">


With the Channel lock, remove the clamp that holds the radiator hose (center of picture above, push it towards the engine block) and separate the hose from the thermostat housing. Now, assemble the tools like this, the bottle is just a dimensional reference...


<img src="http://pictureposter.audiworld.com/62820/p6300008.jpg">


Put a rag on top of the open dipstick tube to avoid getting any coolant or debree into the oil. With the tools assembled as above, loose the top bolt that holds the t'stat housing to the block, like this:


<img src="http://pictureposter.audiworld.com/62820/p6300010.jpg">


There is enough space to work the bolt by hand:


<img src="http://pictureposter.audiworld.com/62820/p6300011.jpg">


Now let's work with the lower bolt, like this:


<img src="http://pictureposter.audiworld.com/62820/p6300015.jpg">


when it's loose you'll be able to remove the housing from the block, it will look like this:


<img src="http://pictureposter.audiworld.com/62820/p6300017.jpg">


Remove the old o-ring and pull the old t'stat from the block, if you do a quick change (quick as in normal, not lightning fast) you should loose only very little coolant. Remember that the o-ring goes on the outside, over the t'stat! Now it should look like this:


<img src="http://pictureposter.audiworld.com/62820/p6300018.jpg">


Time to reasemble. put the housing back in place, caution to not move the o-ring, the housing should be flush with the engine block. Hold everything with the top bolt, which can be worked by hand, like this:


<img src="http://pictureposter.audiworld.com/62820/p6300022.jpg">


Now, with the magnetic pickup, hold the lower bolt like this and insert it into the lower hole on the housing:


<img src="http://pictureposter.audiworld.com/62820/p6300023.jpg">


Bolt towards the housing:


<img src="http://pictureposter.audiworld.com/62820/p6300024.jpg">


Bolt onthe housing:


<img src="http://pictureposter.audiworld.com/62820/p6300025.jpg">


Now, use the short 10mm socket and the long extensions again to secure the lower bolt in place, then do the top bolt. Reattach the coolant hose. Now, insert the oil dipstick tube back into the metal base, remember that the square part on the side is to be reinserted on the manifold base later. Release the ty-rap (if used) that holds the tray that we moved to the right and put it back into it's position, on the manifold. Remeber to secure the oil dipstick tube into it's slot and reattach the connector we removed from the left side of the tray.. Reattach the 2 10mm nuts and the 2 5mm allen screws.
Open the coolant reservoir and top it off with coolant or water, depending on how much you did loose. Remember, that the OEM coolant, PENTOSIN G12 (Pink color), DOES NOT MIX WITH OTHER COOLANTS. If you do, it wil gel and create a mess.

After filling the coolant, reattach the battery and turn on the car, leave it idling for 5 minutes and keep an eye on the coolant level, as it may empty the reservoir filling the bubbles on the block. After the engine has idled for 10 to 15 minutes, check for leaks and go for a test drive.

Hope this helps!

Enjoy!

The Lab.

RussAdams

Yesterday I successfully followed RafaTT's writeup to replace my thermostat. It was an easy job, though a bit finicky to accomplish. I used a 1/4 inch drive to accomplish the job. Swivel headed 10mm socket and a long extension did the trick. Using a magnet to get the bolts back in place was THE best tip! Took about two hours on my 2001 Audi TT Quattro. I replaced the thermostat, housing, and oil stick tube while I was at it, even though it did not break.