Those I've had apart use an O-ring to keep the engine coolant on the inside. I would also try squeezing it a bit using the large nut, cleaning it up and keeping a close eye on the results for a while.
--
Art Benstein near Baltimore

“How much does a chimney cost?”

“Nothing, it’s on the house…” or "It's gone through the roof..."

I use my car for daily commute to work. So if according to me, I'd replace the radiator if more than 10 years old, leak or not (to avoid nasty surprise). With that being said, the 940 is truly a "luxury" car in my book. Even if you have a leak, there is still time (ie.luxury) to do some minor repairs, like doing the brass nut as Spook suggested. Of course now you must plan or start saving for replacement.

Still on topic of radiator I think its best to get OE replacement as I like the OE style of drain cock which uses 13mm plastic nut. Easier to drain the coolant. Just use a 13mm long socket. The Nissens I have now uses a plastic screw with too small a tab to turn it open with fingers, I had to use pliers instead, thus making the drain job a bit more difficult.

And yes its repairable, just tighten the big nut a bit.

Amarin

Dear otherdalek,

Hope you're well and stay so. If the radiator is over 10 years old, it is close to the end of its service life. Plastic embrittles with time and exposure to heat. So, a radiator that lives where ambient temperatures are "high" (i.e., >90°F for weeks at a time) will be have a shorter working life, than a rad that lives where ambient temps are lower.

The brass threaded nipple, to which the automatic transmission fluid (ATF) pipe connects, is braze-welded to a double-wall copper cylinder, used to cool the ATF.

I know this, because I "post-mortemed" a Nissens rad at the end of its service life.

There is a thin ring of sealant between the inner wall of the radiator's side tank and the copper cylinder. That seal may have failed. But you can turn (tighten) the large brass hex nut. Doing so may cure the link.

Old plastic gets brittle: go very gently to avoid cracking the plastic side tank, which is sandwiched between the brass hex nut and the ATF cooler.

Use a fine wire wheel to remove the green "grunge" from the hex fitting. Then, wrap clean white paper towel around the hex nut. Drive the car. See if the paper towel is still white. If so, you've stopped the leak. If not, turn the hex nut another 1/16-turn and wrap more clean white paper towel. Repeat until: (a) the leak stops or (b) you can't move the nut using gentle pressure.

Please post with your results.

Hope this helps.

Yours faithfully,

Spook