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Diesel Oil pressure Low then it stalls

4K views 7 replies 4 participants last post by  Turbotojo 
#1 ·
Hi everyone

i got an old 300D 1976 115

i am having a few little problems and i'm wondering can anyone help because i absolutely LOVE LOVE LOVE this old benz..:rolleyes:

i ran the car on veggie for a while and it ran fine.

she drove great up until recently.

now the car starts up perfectly first turn of the key..
but next what happens is no so pretty, what happens is the car warms up to normal operating temprature and as it does the oil pressure drops drops drops slowly to 15 psi then stays there for a while then drops to 0 and stays there for a a minute, then stalls, and she will not start again until the whole car has cooled down for half an hour.

There is a funny , slightly noticeable tapping noise coming from the engine as well.
sometimes the car smokes moderatley, sometimes it doesn't smoke at all.

I put some heavy weight oil in there to try and build some pressure and replaced the oil filter. it made no difference what so ever. I cleaned the fuel tank out and filled with clean white diesel, just to eliminate that for any veggie haters out there,

could i have blown bearings? or oil pump? if someone could give me some input it would be great as i dont want to let this old car slip away over to the dark side...:roll:
 
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#3 · (Edited)
It would be nice to know the milage on the Engine.
I would not run the Car until you know more.

I have read that the Oil Pump Pressure Relief Valves have been known to stick or even Break; and the Oil Pressure Relief Valve Springs have been known to break.

If you want to investigate that when the Oil Pan is off look in the bottom of the Oil Pan and the Oil you drained out for bits if metal that would indicate a Bearing has melted.

Another issue is that unlike the later models that have a Ratcheting Device on the Timing Chain Tensioner Piston on yours the Oil Pressure is a much more important part of keeping the Timing Chain tensioned properly.
 
#6 ·
Strange.

I've flogged several of these engines to near death but they would not die. Did get a noticeable ticking noise in the last one though and it turned a bit smokey but no oil pressure probs. I just parked it up and bought another one.

I'd like to hear the out come of this if possible.

Cheers.
 
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