New Radiator?? on a '90 V8

[Andy Tiura <ATiura@engpo.msmailgw.intermec.com>]

Hi.

A week ago my '90 V8 suddenly overheated.

This car has always run on the cool side of normal (like ~90C) and then one 
day while motoring at about 45 MPH BAM! the needle all of a sudden climbs 
straight toward 120C and I drive for the shoulder.  There's a little water 
sprinkled around the neighborhood of the water pump... and the beast seems 
pretty warm... so I had it flatbedded 25 miles to the dealer in Seattle.

Since I was leaving town for a week, I scheduled the 60k mile service as 
well as a water pump replacement, told them that the car had overheated but 
had been immediately shut down, and then ordered the belts and pump from 
Carlson...  boy I felt smug.

Some days later, the dealer calls me in Chicago to say:  "Your radiator is 
all plugged up."

I say: " What!  Don't they crud up rather gradually?  This is a sudden 
cooling system failure... it sure feels like a thermostat to me!  Don't you 
dare replace my radiator."

They say:  " We checked your thermostat and it's ok.  Have a nice day !"

Upon getting the car back, it overheats again just two miles from the shop. 
 So, I get it trucked back to the dealer.  And, naturally, the diagnosis is 
the radiator for a mere $750 plus labor.  I told them to roll it out to 
their lot while I think things over.

Really, I'm not usually this stubborn.  But I've had several thermostats and 
radiators go south in other cars I've owned over the last couple of 
decades... and I've never experienced a sudden radiator "heart-attack" like 
the dealer claims the V8 has suffered.

Other radiators have gradually lost efficiency until it was no longer 
adequate... and this degradation would happen over a few thousand miles and 
yield a little advance warning of doom.  Have I just led a charmed life 
'till now... is a normal radiator failure usually a sudden thing?

Is there something special about the V8 radiator metallurgy or coolant 
chemistry or ??? which can constrict the flow just all of a sudden?  Has any 
other V8 owner had this very same symptom with the cause being the 
radiator??  And have you heard of a radiator plugging up at just 50K miles?

Do you know of a Seattle area radiator shop that will tackle repairs 
(cleaning out) to a V8 radiator?  Is there an aftermarket radiator which 
lacks the Audi logo but sells for a couple hundred instead if 0.75 grand??

Thanks for any advice you can provide.

 -Andy Tiura
atiura@intermec.com