Hi Nick,

Sounds like we have some similar mileage on our cars. My 87 760 has 252,000 miles on it.

I'm a little concerned about coolant loss too and am worried about possible head/head gasket problems. Is it possible it's accumulating in the valley under the intake manifold and evaporating off?

Regarding the o-rings I got this response from a delorean message board on the subject:

"I had a leak in the exact same place on my PRV. I used the O-Rings
from John Hervey's kit, and it worked just fine for me. They're nice
and thick.

To torque everything down, I first chased the threads with a tap, and
installed new bolts, just in case the old ones were streched out.

When I torqued everything down, I held the Y-pipe in place with one
hand to keep it flush, as I hand tighened down the bolts, and then
backed the one bolt out, so I could install the heater pipe. I then
slowly torqued everything by hand, using a star pattern on the 4
bolts. And THEN I installed the water pump with new silicone hoses.

Pressure tested @ 14psi for 20 minutes, and nothing leaked then, nor
since."

My 760 is pressurized at 21psi (i think) but other than that his procedure seems valid.

John Hervey/ http://www.specialtauto.com/ has a kit that includes 4 new bolts and o-rings. I may try that if the problem persists.

--
Carter