Variable oil pressure

My 1983 Suburban (6.2 diesel) has always had steady 40 psi oil pressure. Lately however the pressure is all over the place, varying between 10 and 80 psi. I changed the oil and filter (it was about time anyway) but no
change. I always keep the oil level topped off, and since I have an oil leak (that predates the pressure problem) that I havent gotten around to fixing, I check my oil level daily.
What things might cause oil pressure to start varying like this, and what can be done to correct it?
TIA, Warren
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Oil pump pressure relief valve or trash in the pan...... Either way u gotta drop the pan to fix it. Are u sure the gauge is working correctly and is not screwing with your head, obtain a mechanical gauge and double check if in doubt.
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Mad-Dog
'79 Chevy K-10
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Warren Post wrote:

The first thing that you should do is change the oil pressure sending unit. GM oil pressure sending units have always been notorious for doing this kind of thing after a while. I've replaced literally 100's of them for this type of complaint. Start here, and if that doesn't fix it, you will have to dig a little deeper. If you don't want to spend money on a sender that may still be ok, then you will need to get a mechanical gauge and check the oil pressure with that. But I'd guess that the unit is faulty.
Ian
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I'd agree with the gauge. Usually an oil pump either works or it dont. Not typically sparatic. Gauges however will go sparatic. I mechanical line type gauge will not lie to you. If it leaks you will see oil so they are pretty trustworthy. Also very inexpensive. I think I seen them at Wal-Mart the other day for 6 bucks. Cheap and easy way to diagnos your problem. Good Luck. LKN4SNO

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. .
=================Warren Post wrote:
<snip>
What things might cause oil pressure to start varying like this, and what can be done to correct it?
==========================Shiden Kai wrote in.....
The first thing that you should do is change the oil pressure sending unit.
<snip>
Ian ==================== snipped-for-privacy@verizon.net (LKN4SNO) agreed with.....
I'd agree with the gauge. Usually an oil pump either works or it dont.
<snip>
LKN4SNO ========================marsh put motion to vote with......
I third the motion at hand. all in favor ..? so be it !!!
Motion has been approved by a show of hands!
jest don't git no oil on yer fez......
next item please
MarshMonster ~:~ ==================
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Thanks everybody. Ill check that gauge.
Warren
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