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  #1  
Old 09-16-2010, 09:52 AM
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Question please help..om617 shaky oil pressure??

Goodmornin. I woke up to real shaky oil pressure on my 84 300tdt. What could be cause of this and should I not be driving it like this?
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  #2  
Old 09-16-2010, 11:02 AM
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When you say shaky...

Does the gauge fluctuate significantly (bounce etc)? Does it start with low pressure? Does the low pressure stay that way?
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Old 09-16-2010, 11:57 AM
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I'd guess he's refering to hot idle pressure.

Min idle should be 0.5 bars, and by 1500 rpm it should peg the gauge @ 3bars. Use a diesel rated 15W40 motor oil like Delo to minimize the effect. Too low of an idle speed with make things seem worse than normal.


Michael
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  #4  
Old 09-16-2010, 12:37 PM
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There was a TSB on on shaky 123 oil pressure gauges and a fix. It involves placing an object in the oil gauge line. someone on here did it and I seem to recall that it worked.
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  #5  
Old 09-16-2010, 05:32 PM
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Shaky oil pressure is often due to bad rod bearings or leaking pressure regulator.
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  #6  
Old 09-17-2010, 12:41 AM
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Shaky

Quote:
Originally Posted by kerry View Post
There was a TSB on on shaky 123 oil pressure gauges and a fix. It involves placing an object in the oil gauge line. someone on here did it and I seem to recall that it worked.
I has forgotten about that. My almost new '78 300D's oil pressure gauge developed a bit of palsy and the fix was a small sliver of plastic (an MB repair kit, came in a little plastic bag) which, after unscrewing the oil line to the gauge, was inserted into the gauge input, pointed end in, then reinstalling the line. This damped out the pulses from the pump at hot idle.

The only unexpected effect was that on cold startup, the pressure was perhaps one second slow to indicate.
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Old 09-17-2010, 12:48 AM
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Quote:
Originally Posted by kerry View Post
There was a TSB on on shaky 123 oil pressure gauges and a fix. It involves placing an object in the oil gauge line. someone on here did it and I seem to recall that it worked.
Updated the thread not too long ago,

http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1531707-1981-300-td-chattering-oil-pressure-2.html
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  #8  
Old 09-18-2010, 12:10 AM
RML RML is offline
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It could be as simple as the O-ring on the shaft that goes down through the oil filter. If that gets hard, brittle and breaks off, it will cause the needle to fluctuate. It is simple to replace so I would recommend starting there.

Richard
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Old 09-18-2010, 07:10 AM
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x2 on the o-rings. I had a vibrating oil gauge on my wagon. I picked up the MB part and then read about the o-rings. I decided just to try the latter as the quick fix. One o-ring was pretty sloppy. Replaced them both with the correct sized ones and so far the vibration is gone.
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