'85 5000S Thermal Oddity

["Daniel K. Elftmann" <dane@cnt.com>]

My apologigies for the length but frustration dictates.  Bought the car 2
months ago for $1700.  Have been resolving minor issues since.

1) Replaced CAT and pipe between CAT and MUF.
2) Replaced Upper Oil Pressure switch, was blowing Oil.
3) Repaired Door Lock on Rear Door.
4) 
Repaired Central Power Lock system.  Ground wire not connected on vacuum
unit(duh).
5) 
Replaced Battery.  Existing battery was'nt right size and looked like it was
the extra one from someones garage was'nt taking a charge anymore.
6) 
Replaced Ignition Switch.  Last person to change it did'nt tighten the set
screw and plastic was chewed up.  Thanx whoever you are.  Wish them mech.
engineers would stop using plastic, argh.
7) Repaired Rear Power Window(Cable Breakage).  List was helpfull here!
8) Had 115K diff re-inspection done at dealer.
9) Installed fuse for pwr seat memory, gee that was easy.
10) Fixed snapped overflow outlet with part from dealer and a little JB weld.

Now on to the problems that the AUDI GODs seem to enjoy frustrating me with:

1) 
Replaced thermostat as Temp. Gauge (TG) was erratic between Cold and Dead
Center or three quarters.  (No change in TG)  But in the process decided to
change both rad hoses.  Upper hose inlet snapped (Aw SHIP, kid was with me).
JB Weld it back together and walla no leaks from any hoses or connections!
New problem.
2) 
Overflow cap not letting out air and radiator leaking at the
Plastic/Aluminum seam after engine shut down.  Replace cap now overflow tank
fills but radiator still leaks from seam after shut down.  OK, maybe I
should budget a weekend and $ for a new radiator, but the spousal units
about had it with the time/$ investment.  I've heard some discussion on
stop-leak but hesitate to try till I understand TG issue.  

Thermoswitch seems ok, fan runs at low speed with Climate Control Unit(CCU)
on, which keeps TG at 1/2 for 5-10 minutes before nosedive and recovery.
Fan kicks into high with CCU off, but TG oscilates between Cold and 3/4 at
about 2 minute intervals.  I suspect that CCU is bad, since interior airflow
goes to defrost outlets when in (econ,lo,auto,high) and bi-level vents when
in defrost setting. Bentley(87.55) indicates CCU needs replacing.  A/C
compressor never kicks in; could this be related?  Need a weeked to
straighten this out before more investment?

Cleaned contacts on Thermal Sending Unit on inlet to engine block with the
rubber boot? No Change.  Should I replace at ~$100?

Ok, The floor is open can anyone help this dangerous E.E. messing with
mechanical stuff headed in the right direction.  Guess I should've listened
to Dad and become a M.E., ah well that's antifreeze under the car.

Thank You,

Daniel K. Elftmann
Senior Design Engineer
	  &
ECAD Administrator
Computer Network Technology Corporation
Maple Grove, MN 55311
Phone:  612-550-8259
Fax:    612-550-8800
E-Mail: dane@cnt.com
WWW:    www.cnt.com