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low oil pressure


joeb

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96 sts. 121k miles. oil light flickered today at idle. went off when i revved higher. never seen that before. drove 20 miles to store. came out, started car, low oil pressure. moved 100 ft to better spot. shut off motor. oil level fine. last year, my oil cooler line blew off at stop light. engine was idling. no high rpm. towed home. fixed line, car ran fine. i let it idle today for a minute. i can hear a slight rattle on the top end. what to do next? lets assume oil pickup is ok in pan. double check torque on balancer bolt? how do you inspect oil pump after removing it? how does a shop proceed?

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I would like to learn more about that balancing bolt. I understand a few years ago there was a recall on that. Several of us on the board have a similiar issue on our '96 era N*'s. So far we have concluded it's the case half seal. no one has ever heard any noise from our engine, so you may have something else going on. following this issue on this board, it has been mentioned that the oil pump is bulletproof - which is good news, as I believe to remove it is MAJOR work. GOOD LUCK

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Check your oil pressure switch, a bad switch can cause a light

What type and viscosity of oil are you using?

When did you change oil last

You didnt have low pressure long enough to cause a problem dont worry about it

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oil is at 35%. i use 10w-30 in the summer. BBF, i know your trying to calm me down but i don't feel good about this. a motor is usually never run without oil pressure. just a fact. so last summer was instance 1 of potentially causing damage. i had the heads off and it ran several minutes with a top end rattle due to the lifters being dry? thats instance 2 of excessive wear. the balancer bolt was replaced so it may not be at the proper torque so maybe the oil pump has never been spot on since i did the heads? its not like the motor has lead a charmed life.

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oil is at 35%. i use 10w-30 in the summer. BBF, i know your trying to calm me down but i don't feel good about this. a motor is usually never run without oil pressure. just a fact. so last summer was instance 1 of potentially causing damage. i had the heads off and it ran several minutes with a top end rattle due to the lifters being dry? thats instance 2 of excessive wear. the balancer bolt was replaced so it may not be at the proper torque so maybe the oil pump has never been spot on since i did the heads? its not like the motor has lead a charmed life.

A shop can measure your oil pressure (with an external tool). I think it's a rather easy procedure, and it would tell you if you have a real problem or not. As far as I know, Northstars sometimes make little harmless noises, so at least there is a chance that what you hear does not indicate a big problem.

Remember that the engine runs without oil pressure for a second or so every time it's started. So if you shut off the engine quickly that time at the red light, I don't think it should have cased any damage. I am not sure about the rattle after having your heads off. Oil should come up there very quickly after the engine is started (a second or two, I think). And weren't the lifters lubed when it was assemblied? Someone correct me if I am wrong, but I don't think that worn lifters would cause low oil pressure. Isn't oil just sprayed/poured on the lifters? Of course the lifters could have released material that then caused wear on for example bearings (which could certainly give you low oil pressure), but worn bearings usually produces a very noticeable knocking sound. And the oil filter should take care of particles.

I would have the oil pressure checked if I were you. Good luck!

/Jonas

Edited by hjb981
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oil is at 35%. i use 10w-30 in the summer. BBF, i know your trying to calm me down but i don't feel good about this. a motor is usually never run without oil pressure. just a fact. so last summer was instance 1 of potentially causing damage. i had the heads off and it ran several minutes with a top end rattle due to the lifters being dry? thats instance 2 of excessive wear. the balancer bolt was replaced so it may not be at the proper torque so maybe the oil pump has never been spot on since i did the heads? its not like the motor has lead a charmed life.

Im not trying to make you feel good. I am repeating what the guru stated. The oil light comes on, at 5 psi, and your oil light just flashed.

My oil light has flashed a few times also. I have the case half leak and if I use 10w30 my light comes on at idle... I use 15w40 and it never comes on.

Do you have any leaking at the case half?

If the balancer bolt is not to proper torque that could definately cause that light

The guru said that even though the light flashes, there is plenty of residual oil that you would not cause any problems, its extended low pressure that is a problem... Did you get the CHIME and warning light also?, I did

Pre-1995 - DTC codes OBD1  >>

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success. i read that the pressure relief valve can stick sometimes and overfilling the crankcase and reving the motor might help. i reved the motor slowly to 3500 and it did not seem to do anything. than i blipped the throttle several times to 3500 and sure enough the light went off. motor quieted down too. i could hear a valve train rattle at idle before and now it seems to be gone. whether it was necessary to get towed home is debatable. i just did not feel good driving with a funny motor noise and a "low oil pressure" constant chime.

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oil is at 35%. i use 10w-30 in the summer. BBF, i know your trying to calm me down but i don't feel good about this. a motor is usually never run without oil pressure. just a fact. so last summer was instance 1 of potentially causing damage. i had the heads off and it ran several minutes with a top end rattle due to the lifters being dry? thats instance 2 of excessive wear. the balancer bolt was replaced so it may not be at the proper torque so maybe the oil pump has never been spot on since i did the heads? its not like the motor has lead a charmed life.

Im not trying to make you feel good. I am repeating what the guru stated. The oil light comes on, at 5 psi, and your oil light just flashed.

My oil light has flashed a few times also. I have the case half leak and if I use 10w30 my light comes on at idle... I use 15w40 and it never comes on.

Do you have any leaking at the case half?

If the balancer bolt is not to proper torque that could definately cause that light

The guru said that even though the light flashes, there is plenty of residual oil that you would not cause any problems, its extended low pressure that is a problem... Did you get the CHIME and warning light also?, I did

How can the case half leak cause low oil pressure? Do any oil lines go through the case half seal? How can you drive with the case half leak? I thought the oil more or less poured out of the engine if that happened.

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The case half seal is between the lower and upper crank half. The oil must get from the lower end to the upper side, via oil galleys. Not only can the case half leak EXTERNALLY, it can leak INTERNALLY, and drop the oil pressure

Here is photo of the case half and the galleys

engine_20004-1.jpg

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1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

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PRV is part of the oil pump. can be fixed by taking apart the oil pump or sometimes the overfilling method works. i have read about the filling method for priming the oil pump on an engine rebuild or repair. i never really followed the theory since i have never replaced an oil pump before.

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PRV is part of the oil pump. can be fixed by taking apart the oil pump or sometimes the overfilling method works. i have read about the filling method for priming the oil pump on an engine rebuild or repair. i never really followed the theory since i have never replaced an oil pump before.

We saw this happen once before, a member had his car at the dealer and when he picked it up, no oil pressure

Did you lose oil pressure spontaineously?

I wonder if my PRV could be slightly held open slightly with dirt?

Pre-1995 - DTC codes OBD1  >>

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How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

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drove 20 miles, was idling and noticed my oil light flickering. figured hot motor, thin oil? drove 20 miles back and shutoff car at store. came out and got a "low oil pressure" message. would not go off. constant chime. somewhat nerve racking. along with a top end valve train rattle. i knew something was up.

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drove 20 miles, was idling and noticed my oil light flickering. figured hot motor, thin oil? drove 20 miles back and shutoff car at store. came out and got a "low oil pressure" message. would not go off. constant chime. somewhat nerve racking. along with a top end valve train rattle. i knew something was up.

That is interesting that you got a spontaineous message like that, and that you were able to cure it. I as you noted have gotten the oil lite when its very hot in traffic when the oil thins... I never heard valve train noise, I see why you were concerned.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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The post you found about overfilling the crankcase to clear the PRV was originally posted by the GURU. If I vaguely recall he said it might hang open due to a dirt particle.

I never checked my crank bolt maybe I should have, I dont think it would be too hard to access from the wheel well

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

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yes, i tried to turn the bolt. easy to reach. but i do not have a flex plate locking tool. what do you think the torque value is? i know it is x foot lbs and 120 degrees? but what does that translate too, in ft/lbs?

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yes, i tried to turn the bolt. easy to reach. but i do not have a flex plate locking tool. what do you think the torque value is? i know it is x foot lbs and 120 degrees? but what does that translate too, in ft/lbs?

That is a good question, I would imagine that here is a chart someplace that can provide equivalencies, based on size the thread pitch

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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bbf, you have gotten an oil light flicker but never a low oil pressure message? it says stop motor, low or no oil pressure? maybe a oil light flicker is 4psi and "stop motor" message is zero psi. ohh, and you get a constant chime. not good.

Edited by joeb
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After I did my ISS Speed Sensor, when my engine has no oil in it and it was no run for a month, I got the light and got the chime and message, I immediately went to 15W40, and never got it again. I assumed that my case half seals shrunk,

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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yes, i tried to turn the bolt. easy to reach. but i do not have a flex plate locking tool. what do you think the torque value is? i know it is x foot lbs and 120 degrees? but what does that translate too, in ft/lbs?

That is a good question, I would imagine that here is a chart someplace that can provide equivalencies, based on size the thread pitch

I don't think you can correlate a basic torque value to a torque-angle spec. If you suspect the bolt is not tight enough, it would be easier to loosen it, torque it to 37 ft-lbs and then an additional 120 degrees. You don't need an angle meter in this case since the spokes on the balancer are 120 degrees apart - just put a mark on the bolt next to one of the spokes and tighten the balancer until the mark on the bolt aligns with the next spoke.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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yes, i tried to turn the bolt. easy to reach. but i do not have a flex plate locking tool. what do you think the torque value is? i know it is x foot lbs and 120 degrees? but what does that translate too, in ft/lbs?

That is a good question, I would imagine that here is a chart someplace that can provide equivalencies, based on size the thread pitch

I don't think you can correlate a basic torque value to a torque-angle spec. If you suspect the bolt is not tight enough, it would be easier to loosen it, torque it to 37 ft-lbs and then an additional 120 degrees. You don't need an angle meter in this case since the spokes on the balancer are 120 degrees apart - just put a mark on the bolt next to one of the spokes and tighten the balancer until the mark on the bolt aligns with the next spoke.

Kevin can this be performed through the wheel well?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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