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Discussion Starter · #1 ·
It's a 95 9c1 with 79000 on it and at warm idle its down to 2 or 3 psi I thought it might be the stock gauge was messed up so I got a mechanical and it's still low I just changed it to 10w40 100 miles before this stared
 

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whats wrong with 5w30?
 

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Discussion Starter · #3 ·

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If pressure is bad after it was changed, then its the oil that is the problem not the engine. Dump the 10W40 out of the engine and put 5W30 oil back in, which is what the factory calls for. 10W40 hasn't been needed in automotive applications since the 70's or early 80's. With the advent of new manufacturing processes engines are built to a lot tighter of specifications so that manufactures recommend 5W30 or even 5W20 in some applications. Also for the record the oil pressure minimums should be 6 psig at 1000 RPM (not idle which would obviously be lower than that), 18.0 psig at 2000 RPM, and 24 psig at 4000 RPM according to the service manual for the 95 B-body (for both LT1 and L99 engines). - Peter
 

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Discussion Starter · #5 ·
If pressure is bad after it was changed, then its the oil that is the problem not the engine. Dump the 10W40 out of the engine and put 5W30 oil back in, which is what the factory calls for. 10W40 hasn't been needed in automotive applications since the 70's or early 80's. With the advent of new manufacturing processes engines are built to a lot tighter of specifications so that manufactures recommend 5W30 or even 5W20 in some applications. Also for the record the oil pressure minimums should be 6 psig at 1000 RPM (not idle which would obviously be lower than that), 18.0 psig at 2000 RPM, and 24 psig at 4000 RPM according to the service manual for the 95 B-body (for both LT1 and L99 engines). - Peter
So what oil should I use and should I use lucas stabilizer or zmax?
 

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Just use a good quality 5W30 oil. Since your engine is likely higher mileage I would stay away from the synthetic oils as they cleanse the engine of deposits, some of which invariably are stoping some seal leaks and by switching to the synthetic oil will cause the now "plugged" leaks to leak. I would also stay away from lucas stabilizer, zmax and most other oil additives. My take on that is if they really did anything the car companies would all be saying to use them. - Peter
 

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Discussion Starter · #7 · (Edited)
So say it don't fix my pressure problem just changing the oil then what?
 

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Also for the record the oil pressure minimums should be 6 psig at 1000 RPM (not idle which would obviously be lower than that), 18.0 psig at 2000 RPM, and 24 psig at 4000 RPM according to the service manual for the 95 B-body (for both LT1 and L99 engines). - Peter
If your oil pressure is equal to or higher than listed above, and the engine isn't making any unusual noises, just drive it.
 

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Discussion Starter · #9 ·
If your oil pressure is equal to or higher than listed above, and the engine isn't making any unusual noises, just drive it.
It is making some weird noises now
 

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Discussion Starter · #10 ·
It is making some weird noises now
And It fluctuates from 10 psi to 20 then back to 10 at around a grand And it's startn to sound kinda off
 

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Change the oil and replace it with 5w-30 hopefully that will give you the oil pressure you had before you made the switch. 5w-30 is what i run with no problems.
 

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1996 Caprice 9c1, 2018 Ram Laramie CC 4x4 EcoDiesel , '03 Ram 3500 Laramie Sport QC 4x4 Cummins
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I've seen oil pressue drop with crappy made oil filters. Make sure your filter has a anti-drain back valve which is pretty much standard on better filters. Stay away from the least expensive oil filters,the ones always on sale. Stay away from the cheap Fram filters.(I don't buy Fram period) In my opinion,also stay away from Champ,Pennziol,Quakerstate,STP oil filters. This link provides a wealth of information on how filters are made and designed. Be sure and jump around some of the other links on his site. +AA on a good 5w30 oil.
 

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If you're worried about the engine's condition, drain the oil into a clean pan and look at it in the light. If you see anything sparkling, its metal shavings, which means you're going to need a new engine.
 
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