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Old 08-01-2020, 11:19 PM
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Join Date: Feb 2003
Location: TN
Posts: 303
Oil Pressure Oscillation at low speed and idle

My 1984 123 OM617 with 440k and owned for 16 years just started doing this rapid oscillation at the oil pressure gauge at low speed or idle. The oil pressure is pegged out the same as usual at speed but at lower speed or idle it drops to about half way on the gauge as usual and then rapid, short arc oscillation. This doesn't seem good. The old timer runs great otherwise. The oil level is OK and changed at 3-4k intervals with good quality oil.
I searched and can't seem to find another example. I don't want my engine to lose oil pressure and die. Has anyone seen this before ? Is this a warning sign ?

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Old 08-02-2020, 12:22 AM
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Join Date: Sep 2001
Posts: 1,493
My '85 did this on very long interstate trips when stopping for a break, it seemed to go away and was never a problem.

Good luck!!!
Does a Caddy stretch? No, but a Mercedes bendz.
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Old 08-02-2020, 12:50 AM
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Join Date: Sep 2007
Location: Long Beach,CA
Posts: 37,419
Change the O-rings that the bottom of the tube on the Oil Filter. There is also a spring loaded valve inside of the last 1/4th of the tube (I don't know how to access it). See if the new O-rings help.

"but at lower speed or idle it drops to about half way on the gauge " When mine is hot it drops down to about 1.5 bar on the gauge at idle. I believe in the manual it can go as low as .5 Bar and still be OK.

Personally I would also change the Oil Filter with a decent quality one and see if that changes anything.

You could also check your Oil Cooler Hoses after driving a bit to see if they are both getting hot. If not the Oil Filter Thermostat has not opened.

84 300D, 82 Volvo 244Gl Diesel
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