Yes, always use this reference point when looking
to purchase any E3, 80 and older - bad, 81 and newer - good.
Yes, Somewhere in '80, BMW redesigned the water jacket
to add more metal to fix the cracking problem (cracks from the exhaust
valves to the water jacket). I, personally, would look for a casting
date of 81 or newer to avoid any error. If you have to replace the
head figure on $300-350 to purchase a used rebuildable head, and
all of the cost to do the work ie: rebuild-valve job, R&R heads,
etc. Also, if you use a mechanical fuel pump and do not want to
change to electric, most - all heads must be drilled for the cam
follower rod for the fuel pump.
No, there is no OEM replacement radiator and no cross
reference to other series that will fit. At one time a "Desert"
radiator was cavliable, I don't know about now.
BUT.... There is a solution. There are new "cores"
avaliable to replace the original "2 row" core. The number of"rows"
relates to the number ot finned tubes that cross form one tank to
the other. There are 3 and 4 row cores avaliable, a radiator shop
replaces your old core with one of the new cores and it will increase
cooling efficiency 100% or better. If you look at your radiator
end tanks, you will see that there is 18mm of thickness avaliable.
To explain: your tanks are 48mm wide, the core is flush with the
side of the tanks that face the fan, but the OEM core is only 30mm
thick. the additional rows can be added towards the front and no
one can tell. I would suggest against the "MOre is better" syndrome.
I had mine recored with a 4 row core, better cooling, but the smaller
tubes (had to make them small to fit twice as many in the same space),
they clog up sooner and are more dificult to clean, so the last
time I had to re-re-core after only 5 years.
Yes, if you buy from those that specialize in older
cars, such as Mesa,
they will help you get the coldest thermostat. Beware! Do not use
these colder thermostats in any new Bosch Motronic engine management
systems, some will keep it from going into closed loop, and if you
think you had problems passing emissions before.