Greetings all. I have recently aquired a 1978 300D. The PO didn't drive the car very much and didn't do a lot of maintenance other than yearly oil changes. Now that I am driving it daily there are little issues that keep surfacing and need to be dealt with. I've been on half pay for months recovering from knee surgery, so I can't just hand the car off to a mechanic with a list, I need to do a bit at a time myself.

The car itself drives really well. Seems to have plenty of power, idles pretty smoothly. Has more power than the 75 300D I had ten years ago. Does not like going up steep hills, but I suppose that is to be expected. The car does not make any smoke, even flooring it up a steep hill I see nothing in the rear view.

Does not like starting in the cold, I have to leave it plugged in over night if I want it to start and it's below freezing outside. If it sits somewhere for more than 6 or 7 hours after it's last run I have to crank it for a solid 45 seconds to get it to fire. I double cycle the glow plugs, and let them run for 10 seconds after the relay light goes off. It seems like there is one "reluctant" cylinder that doesn't fire up as fast as the others. If the car is warm it fires up almost instantly.

I have had the car for two months now, it has been driven daily; short half hour in town stuff mixed with at least once or twice a week spending several hours on the highway. I have had to top the oil up once in that time. I can't give exact mileage because the odometre/speedo is the Canadian model and of course it stopped recording mileage almost instantly. It was at 330,000 km when it quit.

The car has blowby, it wants to push the oil filler cap off and puffs like a locomotive. Other than that though it idles smoothly and has good power.

So far I've replaced the injector return lines, which were starting to leak and so old they were like straws, and put in a new 850 CCA motormaster battery that cranks the car over with a lot of authoritah.

Here is the list of issues, which should I tackle first?

(1) The glow plugs are the old loop style. They are at least 12 years old. One plug was replaced 12 years ago, the others must be older than that. The relay light works as it should, and the zig zag glow plug wires get fairly hot; the one closest to the rad actually melted an exploratory pen cap. I want to do the replace with pencil plugs things.

(2) The alternator belt is loose and somewhat glazed. The car squeals if it's a "wet" (snow is melting) morning and I put the headlights on. If it's dry or I leave the headlights off it doesn't squeal. It charges the battery up (I never lack for amps no matter how much I crank or how many times I start the car in a day). I tried the soap trick and the squeal stopped for a while.

(3) The air breather elbow hose that connects to the top of the valve cover is leaking oil right where it connects to the valve cover. It's a fairly slow but steady leak down the passenger side of the engine. If I clean off the top and passenger side of the valve cover it'll be oily again after a day.

So how should I tackle this and which one should I do first? Any feedback or advice would be greatly appreciated, and have a good day everyone.