Grant wrote:

<<I've had green coolant that has not been changed in the 10 years i've
owned my 85 GL. No leaks (except for the rear heater) and it doesn't
overheat.  I've added coolant over the years but have never changed it.>>

...and Mary had a baby without ever lying down with Joseph. Miracles
happen.

If I were you though, I'd think about changing that coolant. It does a lot
more than keeping your van from overheating. Yours is likely laden with
multi-viscosity gunk, enriched goobs of engine goo, and triple-phase
corrosion crud. Plus all of the good stuff in the ethylene glycol is now
broken down into the useless constituent parts of green coolant: Lime
Jello, Maple syrup, and Cheap Vodka. Time for a change.

gmb