5ktq Radiator Update, and a Type 44 tip

[Mike Veglia]

Thanks again to all who offered radiators for my car. I wound up getting a
good condition Modine all metal one at my local Pick-N-Pull, only to find
that the shroud didn't fit (radiator was from an '84ish NA engine car). Hmm,
TPC's listing only calls for one part number radiator in type 44s--so what
to do? So, I go back to P-N-P to get the shroud off the car I got the
radiator from--car was gone! What I wound up doing was I pulled a shroud
like mine and did some, uh, modifications (read trimmed it down a little) to
make it fit the metal radiator. Also, spent some time picking up some
treasures for my 4kq so it was a good second P-N-P trip ;-)

I was a bit concerned about the all metal radiator going in being slightly
smaller (~1.5" of length) not having the same cooling capacity, but the
overall size difference was pretty small. Anyway, the car is back together
now. Running at exactly the same temps as ever on the dash gauge, not using
any coolant. Water pump noises the car made when the plastic radiator tank
split are gone. No apparent ill effects from overheating (I didn't overheat
it badly at all, thankfully the radiator let go close to home). All is good
and now I can get back to thinking about AC Compressor replacement and front
suspension overhauls on my tq. FWIW, this was a sudden tank split failure in
a ~50k mile and 4 year old AKG German radiator.

Now for the tip. I found it odd that the "no coolant" warning never came on
despite the coolant bottle being empty. Apparently Audi opted to use a N/O
switch that closes contacts when coolant is empty. This means an open
circuit defeats the functionality of this sensor. Combine that with the
behavior of the coolant temp sensor when not immersed in coolant (will read
pretty much normal on the dash gauge most of the time) and you have a recipe
for disaster (which I narrowly avoided it turns out). When I had everything
apart to replace the radiator one of the things I made a point of was to fix
the low coolant detect (got a used overflow bottle/switch from P-N-P just in
case). Turns out the wire going into the crimp connector_inside the plug_had
corroded through and parted ways with the connector. Grabbed a new connector
at P-N-P and spliced it on--problem solved. That connector is easily
overlooked (what with being buried underneath the coolant overflow bottle),
is very vulnerable (what with pointing straight up and having a nice little
rubber boot to help keep the moisture trapped around the crimps to help the
corrosion process), and really is your only really good early warning of
cooling system problems prior to steam belching from under the hood. Next
time you're flushing/changing coolant be sure to check that your low coolant
detect on "autocheck" is working!

Mike Veglia
Motor Sport Visions Photography
http://www.motorsportvisions.com