WILL A 4.2 V8 WITH 100K RUN A FEW DEGREES HOTTER THAN THE NORMAL NO MATTER THE TEMP. OUTSIDE?? IS 80 DEGREES THE NORMAL TEMP ???

WHEN THE VOLTAGE DROPS, DOES THE OIL PRESSURE DROP AT THE SAME TIME ???

When you say 4.2 V8 are you talking about the M119 DOHC engine from the W124 and W140? (400E, E420, 420SEL) If so they run a bit warmer than the 6's in the W124's for sure. I don't have as much experience with them in the W140's but in the W124's the car will run 80-85 cruising, and about 100 C sitting in traffic with the A/C on. If the temp gets above 110 C at any time or stays at 100 C while driving at highway speeds you may have a problem. If it just creeps up a little while idling in traffic that is normal. You should hear the electric fans come on when it gets a bit over 100C. The fan clutch should also engage at about the same speed.

Lee