1stimer,

Great looking car. Sounds like it is in very good shape. As for some of your problem areas:

The squeal needs a little more data to figure out and I am not familiar enough with fixing air conditioning to offer much help there. But the fuel filling procedure on these cars is one of those items I am familiar with, and one you will also become familiar with over time.

The tank is a 17 gallon tank, I believe, so a full tank should be worth over 450 miles. The level indicator is something it seemsMB created, and then reused in many cars for decades thereafter, from left over parts from some electromechanical device that never worked in WWII. They never seem to indicate anything like the real tank level, with the exception of that light. You will get used to either fixing it all the time, or judging fuel available by keeping track of mileage between tank fill-ups. I set the trip odometer to zero at every fill up, and in the mid 350's will fill up if I pass one of my known Diesel stations. Diesel fuel foams like crazy, and if you pump it into the tank at full flow, it will partially fill the tank volume with foam. The more foam in the tank, the less volume available for liquid Diesel. And the foam will activate the fill nozzle shut off valve. So, you learn to avoid filling the tank with foam. On my Diesels, a full tank will indicate past the full mark on the gage.

The oil pressure gage indication you have described is normal. When you have the engine running under load, above idle speed, the needle should be pegged. At idle, fully warmed up, it is ok to drop down even below 1 atmosphere.

The erratic glow plug light performance is an indication something in the system is amiss. Either a bad plug or two, or the fuse as noted, or the relay. I have seen many plugs go, and have yet to actually experience a blown fuse, or a bad relay.

Good luck, and enjoy the new car. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)