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Re: radiator cardboard

   > I've been driving my 85 4KQ around for three years with that piece
   > cardboard missing. I don't think it has much of a purpose; I haven't had
   > any problems with it not being there. As far as replacing it, I can't help
   > you with that.
   Righto!  I dont think my 4kq EVER had that bottom one. The top one 
   however is important, it will overheat without it.

That radiator shrouding plays a substantial role in engine temperature
management, based on my experience with my UrQ and having recently re-
placed all the rotting cardboard pieces. The engine (cyl head anyways,
where I measure the coolant temp) temperature has regulated somewhat
better/more consistently since I replaced all the shrouding. Oddly enough,
it also sits about 10F lower temp too! I find it hard to account for
the lower temp with just the shrouding, but I also disconnected the aux
radiator at the same time (as a test to see if I really need it...). So
with less total radiative capacity (I'm gonna guess about 10 - 15%) and
new shrouding, the engine runs cooler and more consistently. Strange.

Some time ago, there was a, um, thread in this list on whether or not
the UrQ (& 5000 Turbo?) really needed the aux radiator. Back then, I came
down on the "it runs so hot it needs all the cooling capacity it can get"
school of thought, as I watch the "stock" system heat-soak the cyl head 
to well past 250F on shutdown (my gauge pegs at "just past 250"). After
a year or two of further observation, I have come to the measured con-
clusion that installing a lower-temp thermostat ("180" F or "83" C range)
and radiator fan switch ("190" F or "87" C range) with proper ("working")
radiator shrouding provide ample temp control for "normal" conditions,
in New England at least (where it doesn't get all that hot, just yucky).
I have not taken it on a track for sustained 100mph+ banzai driving, so
the jury is still out on that one . . . but I think I am convinced the
aux radiator can be punted safely ("if ya need more, ya need a lot more"
and might as well buy the mega$ higher capacity main radiator). [Now, to
get an intercooler to $tuff into the aux radiator $lot!]

By the way, new replacement shrouding is made from artifical long-chain
polymeric stuff ("plastic") so it will hopefully last longer than the
original cardboard crap!