You were correct - hose under the oil filter was very soft. Removed all the hoses, except the ones under the throttle body that were replaced when it was taken off.

Plan to keep this one forever, so I am thinking about a new radiator and oil cooler. Any suggestion for sourcing these, either OEM or aftermarket?

 

New OEM oil coolers are long gone. You can get aftermarket ones, but they do not have an internet thermostat with bypass. I got a decent aftermarket one with -10AN bungs, an Earl's external oil t-stst block, some -10AN nylon braided hose (Earl's), an assortment of -10AN fittings including the 16mm to -10AN and 18mm to -10AN rear iron and front cover fittings. All in probably $500. I like making my on lines. If you go this route, get some good aluminum AN fat wrenches and a vise holder for AN fittings. Don't cheap out on the -10AN hose. The cheap stuff tends to bend more when making tight turns.

I'll get some pics of what I did on my 1979.

 

I had my radiator fixed last month...Cost 439....Could go aluminum for less but reading fitments of different brands I went with my original...Shop said it was in good shape so I'm good to go.....As far as oil coolers Mazdatrix has them.........https://mazdatrix.com/product/oil-cooler-84-85-gslse/

 

Good find on the oil cooler. For that price you can build a better system.

 

I did find an OEM oil cooler at Mazdatrix https://mazdatrix.com/product/oil-cooler-84-85-gslse/ but it is pricey

Pulled the radiator and oil cooler. Found a local radiator shop that can refurbish both and make replacement lines for less than $500.

Anything special I need to know when reattaching the banjo connector at the rear of the engine?

 

Yes. I had two crush washers that I thought were a good fit. Turned out they were just a bit to large. They leaked. Just get the Mazda ones and be happy.