T-Stat Replaced and Heat Question on A4 (Long)

[mkb]

Tools Used
----------------
List of tools used follows:
Long 10 mm 3/8 socket
Short 10 mm 3/8 socket
10 mm wrench
3/8 extension
Grinder (Dremel)
Alligator pliers (?)
Needle nose plier
Bucket
Lots of newspaper

Removing the T-Stat
------------------------------
Well, over the weekend I decided to change the t-stat on my 97 A4 (AEB engine code).  Good news is that it can be done without taking off the front end.  It's a PITA but doable.  The t-stat is held in place by two 10 mm bolts.  One of them is easy to get to.  The other is right next to a bracket that needs to be grinded down a bit before the bolt will come out.  Watch out for the big splash and keep a big bucket handy.

Anyway, got the little bugger out, but needed help from a friend to put the thing back in again.  Best way is to take the hose off from the t-stat housing.  Then you are free to position the t-stat, washer and housing easily.  Make a note of which end of the t-stat goes into the engine side.  Put the easier more accesible of the bolts on first.  Then you can struggle with the harder bolt.  Use the open ended 10 mm wrench to tighten it as far as you can.  Then take a long 3/8th 10 mm socket on a long (3/8th) extension.  Squeeze on the socket and tighten it a little bit more.  Sorry, don't know the torque specs.

Place the disconnected hose back on.  There is a collar on the t-stat housing over which you need to slide the hose clamp over.  We used one of those alligator pliers (or whatever they are called), to hold open the clamp and slide it over the collar.  Again, it's a pain and I was cold, wet and the concrete floor was hard.

Our Bleeding Procedure
-----------------------------------
Ok, so now fill 'er up with coolant/water mix.  Leave the cap off, start the engine.  Wait for the engine to come up to operating temp.  Check the temp gauge.  We saw that the temp gauge was going well past the mid point mark.  Shutdown.  We noticed that the coolant level went down.  Fill 'er up again.  Start.  Put the cap on.  Get to operating temp.  Shutdown.  Remove cap.  Fill 'er up as necessary.  Repeat.  Leave cap open overnight.  Check in the morning and refill as necessary.

Anyway, that's how we bled the system.  Not sure if this is right or not, but the coolant level is stable and we think we've purged all the air in the system because the temp gauge reads dead center.

What This Fixed
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Before the t-stat change, the temp gauge hardly ever moved off the lower end of the gauge.  Now, it's dead center and the oil temp gauge also reads a bit higher.  Previously it was around 150 now it's closer to 225.

What It Didn't Fix
-------------------------
Still no HEAT!  I would have thought that the t-stat change would have fixed this.  So, is the bleeding procedure correct?  Does the engine coolant sensor need to be replaced?  Are the flaps operating correctly?  Not sure how I would check the flaps.  Heater core?  Windshield does not fog up and no coolant leaks inside car nor any odours.

Also, we checked the hose into the top of rad.  It's hot.  Checked the hoses going into the firewall next to the battery.  Was hot also.

Anyway, any ideas appreciated.

Oh yeah, rant on the placement of the t-stat to follow.

--
mohammed
97 a4 18tqa

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