Diesel cold starting

-- Any tips on how to start old diesels 300 after a cold night when parked on the street where you can't plug it in?
-- Some ppl say one should use thin motor oil. what is recommended - 5-30? How
do these numbers work? they don't say on the containers, all of them from 5-30 to 20-50 say pretty much the same thing. i've heard that 15-40 is the only oil one should use for diesels.
-- also, does anyone know what how much power (watts) the default engine block heater draws? Should a 750W power inverter work, from a portable 12 Volt power source? Also, for portable power sources/jump starters, what should be the power or cold cranking amps?
lots of questions, probably asked and answered on this ng, so lots of thanks in advance to whomever wants to handle one or more of them.
-- ps. here's one more - what's wrong when the engine stays cool - goes up to like only 60 degrees instead of around 80, which is the reading I've seen on mb's under normal driving conditions. this is important to me 'coz i want to convert to the veggie oil fuel.
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Forget about using a 12V battery and inverter to power a block heater - it won't.
Oil: Viscosity is what you're reading - the oil's thickness. 10 - 30 would be my choice for winter use and 20 - 40 for summer use. Do NOT use lower than 10 weight oil in this engine. And buy only oil made for diesel engines, not gas engines.
Cold starting depends on a good battery and an engine that's not worn out - has reasonably good compression. Since you're asking these questions in the dead of winter your engine must be good enough to start in the cold. A valve adjustment ensures that no compression is lost due to leaking valves.
The best thing to do is pre-glow the engine two or three times BEFORE cranking it. That will sufficiently warm the prechambers to start the engine when you engage the starter. Key ON, wait for glow light to go out, wait another ten seconds turn key OFF. Repeat, then START.
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Thanks, T.G., and others, for the replies. It was the battery that was bad. I transfered an old one from a 300D and it started right up, but the temp was also up to near 32F, so it could also be warming-up effects. Before the battery went bad, though, it started even at 10-15F.
The car also has a soft sound, not the crisp mb diesel sound. it may be because the previous owner got a portion of exhaust replaced with remade pipe, although i don't know if that would have an effect. the car accelerates very quickly from start (is turbo), but then isn't as fast, and the exhaust sounds like it vibrates somewhat loudly. Maybe that's also the reason the engine temp reading stays at around 60 insead of 80.
thanks.
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No, that would be the thermostat doing that. The last one of mine had this problem new out of the box. WHen they work it's pegges at 83-86 and should stay there. Makes a big difference in winter keeping you warm on very cold days. The heat should roast you once warm and you won't get that at 60C.
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Replace the engine's thermostat if it runs at less than 80 degrees C. after say 2 or 3 miles of driving.
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Use a VOM to measuere each of the 5 Glow plug (300D). Mine got harder and harder to start, when it won't start, I found out all 5 has open circuit. It must have died one by one.
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