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@eviepenn wrote:

Hi Cadillac Jim, I am a first time responder to this web site and I do not even know if I have the right place.  My problem:

I have a 97 ETC w 4.6L Northstar engine.  The car has 172,000 miles on it (I am original owner) but the engine only has 95,000 miles.  Was replaced at about 77,000 miles.

 

My current problem is "oil pressure low STOP ENGINE" line comes on after the car is warmed up.  As long as I am giving the car gas, the light is out.  As soon as I stop at stop sign the little oil can flickers.  I have been told by mechanic (independent) that is probably is rings.  Is this correct or could it be oil pump or a list of other things.  He is talking rebuild engine for maybe $4000.  Do I need to take it to Cadillac for another opinion or should I believe mechanic? 

 

If this the right place for this question and is anybody home at time time of Thanks for your help.  If it is not you, please direct me to correct place that maybe c an answer my question.

 

EVALEEN Pennington, Cincinnati, OH

 

Bruce

2023 Cadillac CT4-V Blackwing

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Dont panic and have the engine rebuilt, that mechanic is wrong about the rings, that would NOT cause this low pressure issue.  

I trust your oil level is good because I assume your oil level sensor would tell you that your oil is low.  But, to be safe check your oil, just in case your oil level sensor has a problem.

When was the oil changed and who changed it?  If they used a 5w20 that is common todays newer engines by accident your oil pressure would drop, your engine takes 10W30 dino oil.  Do not use synthetic oil it flows 7 times better and as a result could lower the oil pressure in an aging NS, I wouldnt use it in the 93 to 99 Northstars.

Does your engine sound like the lifters are noisy, ticking or clackety?, indicating possible low oil pressure?

How is your coolant temp, summer temps will thin the oil more causing the light and warning.  That will be especially true if you are running higher temps than normal.  What coolant temps are you seeing?, at idle and at highway speeds?  Your ETC should have an oil cooler unless it has been abandoned.

Well, the question is, is the oil pressure low in reality, or do you have a problem with your oil pressure switch, either mechanically or electrically sending a false low pressure signal.  You can replace the sender and make sure that the connectors are making a good connection.  That is the quickest and easiest thing to do to eliminate a potentially false signal.

Immediately change the oil and put  Rotella 15W40 that will protect the engine IF the pressure is low using 10W30, or someone used the wrong grade at the oil change.  Your light will immediately come on less.  And make sure they use an ac delco filter.

The 15W40 is thicker and will raise your oil pressure.  Rotella and Delvac make 15W40, its a diesel oil and has more zinc, which your 97 engine with its 32 rubbing element lifters will love. 

Then have the oil pressure switch changed and the connector cleaned and tightened.  The oil pressure switch is attached to the oil filter adapter behind the front exhaust manifold.

If this is a low pressure problem at idle, I believe is caused by the oil manifold gasket where the seals have deteriorated and pressure is lost internally.  It is quite a big job.  Let us know how the oil change to 15W40 works with an ac delco filter, then change the oil pressure switch and restore and clean the connector, (that will not be an expensive job) make sure your cooling system is working good and report back what you find.

Try to answer the questions I asked above.  Please come back and update us, this topic is a pet peeve of mine and I am very interested in it. 

In the cooler weather, try a high mileage oil, leave it in only 3000 miles because it will be the starburst SN spec and have less zinc. The high mileage oil has seal conditioners that may help with the oil manifold gasket seals.   Then go to Rotella 10W30 for the cold months.  

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Check the oil pressure switch and clean it out. It's probably filled with oil. But your most likely loosing pressure in the main bearings. I have fixed the problem with a undersized main bearing set. Or, you can just run 1540w Rotella. Be sure to switch the oil out to a 1030 before the cold weather hits.

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I had the same issue.  Lots of info above that explains what is going on.  I consider myself lucky that what i tried worked.  I added a bottle of motor honey to the crankcase when i changed the oil.  I now use regular plain old 10w30. My flicker and "STOP ENGINE" would happen after an acceleration, while i was stopped at a light.  Giving a little throttle used to make the oil pressure light go off, then it got worse, and would not go off.  I have a '96 Deville with 114k

 

you can put motor honey in during an oil change, or if your crankcase is a little low. "Motor honey" can be found at most chain auto stores, or walmart etc. like stated above, please keep us informed.  If you try this, i would be interested if it resolves your oil light flicker too.

Edited by winterset
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Hi Bruce and all,

In reply to your info I have checked off your questions as follows:

Oil level is good - no light,  Oil changed about 1 to 1-1/2 mos. ago by same person that told me engine needed to be rebuilt.  Engine runs like a top.  No lifter noise. Never has been (only noise is exhaust system that needs to be replaced).  Coolant temp is normal.  Same as always. I have always changed oil every 3000 miles but that takes me sometimes 4-6 mos. to put on 3000 miles.  Then oil level low light comes on before 3000 miles.  I usually add a quart and can then run for another few weeks before changing. 

I am taking it to Cadillac (the same dealer that has worked on my car for 20 years and has, I believe, been very honest with me.)  I only started taking it to local guy for oil changes the last oil change.  I also want to state that this person stated to me "I don't usually rebuild engines, but I will do it for you".  This sent off some red flags for me and my son.  I am 77 years old and cannot do any of this work myself. I am somewhat car repair knowledgeable but the NS engine is not the usual engine.  Where is a honest mechanic when you need one??????

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Thanks for clarifying some of the questions.  Hearing that the mechanic thought  it was rings made me nervous because that would not be on my list of potential causes of low oil pressure. 

One thing you said in your last post is eye opening "I only started taking it to local guy for oil changes the last oil change.  I also want to state that this person stated to me "I don't usually rebuild engines, but I will do it for you".

Since this low pressure stop engine message just started since the last oil change it is possible that the local mechanic used an inferior oil or the wrong viscosity for your engine starting this issue.   I think taking it back to Cadillac and having them change the oil and inspect or replace the oil pressure switch would be a good place to start. 

The answers you gave to my questions are positive, normal engine temps, no lifter noise, and minimal oil consumption based on 1 quart every approximate 3000 miles.

The dealer will not recommend the Rotella 10W30 or 15W40 unless they fully understand the zinc issue and the lack of it in the starburst SN spec, their stance will be that it is oil used for diesel engines, they will never recommend it. They may even state that the zinc was reduced to protect the CAT. To that let me say, we have never had a large problem with CATS going bad. Furthermore, we are more concerned with high oil shear because of the 32 rubbing element lifters and rotella has 1200 ppm of zinc whereas SN has 700 to 800 ppm.  That you appear to change your oil every 3000 miles may render that issue a moot point.  15W40 will increase your oil pressure in hot weather to turn the oil pressure light off at idle if replacing the oil pressure switch does not solve the problem and you don't want to spend the money for an engine rebuild.  This oil light problem is usually more prevalent in hotter weather.

I have spoken to Shell Oil's tech support people and lots of guys with "older muscle cars" with rubbing element lifters are running Rotella due to its elevated zinc. As you know zinc is an anti-wear compound that is sacrificed over time to prevent metal on metal contact.  We used to have one of the engineers from the Northstar design team here and he once said, the Northstar can take all of the Zddp or zinc you can throw at it!, he is the person who recommended Rotella.  Shell produces Rotella.

Good luck to you and please report back how you make out with this, Mike

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Just now saw the post.  The problem does seem well in-hand.

I do agree with BBF and others that you need to work with the dealer that you trust or another mechanic.  And, the first thing I would do if the car was mine is get another oil sending unit and ask the service tech to change it with an oil change, which I would schedule as soon as I had the oil sending unit in my hand.

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The reduction in zinc is why many oil blenders are now relying on moly, titanium, and boron to provide the necessary anti friction and extreme pressure protection that was traditionally provided by zinc.  And they have no deleterious effect on emissions components and do a pretty good job.  While zinc is interesting, with modern oils, I have grown more fond of those that have generous amounts of moly and boron in them.  

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5 hours ago, Cowpie said:

The reduction in zinc is why many oil blenders are now relying on moly, titanium, and boron to provide the necessary anti friction and extreme pressure protection that was traditionally provided by zinc.  And they have no deleterious effect on emissions components and do a pretty good job.  While zinc is interesting, with modern oils, I have grown more fond of those that have generous amounts of moly and boron in them.  

Ill need to do some research, your other post on the subject provided a lot of info, thanks

Pre-1995 - DTC codes OBD1  >>

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  • 3 years later...

Hello coming from the diesel world i have had great luck with the rotella
the newer blends with moly etc from what i have read tend to be more subject to sheer than the high blend zincs but
if i may make a recommendation based on experience
archoil 1 ounce per quart every other oil change or so has a high level of nano bprate and makes a very real difference in friction and seems to help with sheer.
I run it every change in y diesel and it is absolutely amazing.

otherwise i agree with the sending switch being suspect so long as you are keeping your il clean and it sounds as if you are with 3k .
i would stay aay from the guy who wants 4k for rings which are most ceertainly not the problem. and suspect he used an inferior and wrong grade oil in your car.
for what its worth i came checking tonight because i had the same message pop up and suspected the sending switch and also i am due for an oil change and wanted to see if there were any tips i should know.
i like the rotella t6 ti[ its a god durable oil for sheer i have been running a synthetic 10 30 last change and that may have helped my own warning light to come on...
i have been a fan of valvoline high mileage in most of my high mileage gm vehicles and have had good luck with it over all but will try the rotella t6 in mine next change.
i ran it in our 340k suburban and it seemed to really like it as well. makes me think its a good cross over for gm vehicles not that the 350 and ns are the same motor but ...
anyways thanks for the ti and reassurances i will get my oil changed out over the weekend

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@John Galt what year do you have?  The 93 through 99 have rubbing element lifters and it was designed with dino oil, clearance wise.  The valve lifters are 33mm in diameter and represent 32 sources of pressure leaks as the engine wears.  The lifters tops are lubricated via splash oil from around the lifters.  As the engine wears and the clearance widens those 32 lifters leak more effectively lowering the overall system oil pressure.  If the clearance grows too wide beyond spec, the lifter will collapse at idle, causing a misfire that goes away as the RPM rises increasing the oil pressure thereby filling the lifter.  We currently have a member with a misfire at idle that goes away at highway speeds, I am attempting to have him put a real time misfire count analyzer on it to monitor the misfires throughout the RPM range. 

Synthetic oil flows 7 times better than dino oil, making the 'leaks' even worse.   Keep in mind that the oil light is calibrated comes on at 6 psi and normal oil pressure at idle is 10 psi, which increases to 30 psi at 2,000 rpm.  That 4 psi difference is what causes the light to flicker.  But what concerns me is what is happening at the top of the engine considering that psi drop at the oil filter adapter. Idle oil splash that reaches the tops of the lifters would be diminished, not good. 

I experienced the flickering oil light, as discussed throughout this board.  That flickering oil light and low oil pressure message usually shows up during the summer months based on my own experience and my experience here on the board.  That occurs because hot oil thins out badly lowering overall oil pressure due it more easily finding wide leak points at the main bearings, rod bearings, casehalf seal and lifters.  Using the 15W40 Rotella or Mobil Del Vac lessened if not eliminated the flickering on my 96, but it didn't stop it on my friends 98, and it had a new oil pressure switch as did my 96.  

A poorly performing cooling system causing temps to run higher only accentuates the problem causing oil temps to run higher also thereby thinning it.

I personally would not use synthetic, while its temperature stability is terrific its improved flow characteristic is not advisable on an engine designed for dino oil.  Rotella sells a non-synthetic 15W40, that is a little harder to find but try to find it.

By the way, starting in 2000 the NS used roller lifters with less than half the cross section of the 93-99 lifters, thereby decreasing the potential "leak points" substantially.  But there is still the potential to be dropping oil pressure from bearings and the casehalf seal/oil manifold.  Starting in 2000 synthetic was spec'd from the factory and using it is a lesser concern probably even desired.

That said, I did a search of shell.com I don't see Rotella I now see Rimula. The Rotella T6 is available on Amazon though, but I don't see the non synthetic version.  Further research is necessary.  Ill try to put a call into Shell this week, I had heard that shell was going to decrease the zinc in Rotella and now I don't see but one Rotella (straight 40 weight I think) on their web site unless I missed it.  Ill report what I find out from Shell tech support.

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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  • 3 weeks later...

hey sorry it took me a bit to get back on this.
I've been busy (understatement of the year)
mine is a 2000 and i changed theil to full syn 10-30 toaday and sure as hell the low oil pressure light is on...
kinda thinking i ahould change the sending switch. sorta wondering if i should drive it to town to take the kid to work or take the truck?
I assume it is fine and it is just the lower viscosity syn flow rate but it does make ,e nervous driving something that is telling me it is about to explode lol.

 

update...i did just drive it and light went outand it seems fine
i suspect i will swap out the pressure switch buy a good 15-40 now that i am out of the 10-30 i had already and stop worrying about it lol

 

i need to tear into the truck and do some mods before the snow flies

and i need to cut split and haul another 6 cords or so of wood before that happens too...

in other words i have got more left to do than i am likely to get done...

 

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In 2000 roller cams were used and synthetic was used from the factory.  I wouldn't jump to 15w40 on a 2000.

You might change the pressure switch and clean and inspect the connector and see what you get.  

@John W Galt

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I would change the pressure switch before anything else period. Usually there is a dead giveaway when you unplug it. The oil leaks through the sensor into the plug.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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3 hours ago, BodybyFisher said:

In 2000 roller cams were used and synthetic was used from the factory.  I wouldn't jump to 15w40 on a 2000.

You might change the pressure switch and clean and inspect the connector and see what you get.  

@John W Galt

when i got this is was running ol 10-40 and i have run that in it mostly but i got a great deal on the 1030  synth and thought i would give it a shot

pretty sure my pressure switch is about shot i gotta get the car up again tomorrow and see what style it is and get one ordered.
i did get out and clear all the codes out of it nothing about low oil i have one of the stupid air pumps for the exhoust out and a po742 for the tranny probably a sensor again from what i have read. car drives great
but i do need to do some tinkering with it to get it back into perfect shape.

2 hours ago, rockfangd said:

I would change the pressure switch before anything else period. Usually there is a dead giveaway when you unplug it. The oil leaks through the sensor into the plug.

yea that is my next move for sure.
i did get the message to clear running it for a few minute seems to be running fantastic.
if only i could get my internet to work as well :D
the price of living in paradise
 

Edited by John W Galt
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5 hours ago, BodybyFisher said:

In 2000 roller cams were used and synthetic was used from the factory.  I wouldn't jump to 15w40 on a 2000.

You might change the pressure switch and clean and inspect the connector and see what you get.  

@John W Galt

also..thanks man i appreciate all the info and i thought it had rollers but the heads were off in 2012 and a lot has happened since then for me. LOL

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Let us know how it turns out.  Getting away from the synthetic and with the cooler weather upon us, you should be ok

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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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  • 5 months later...

I purchased my 1995 Cadillac DeVille with the 4.9 back in May 2019 from the grandson who’s grandfather past away sometime in 2017. The grandfather was the owner of the car (title never changed after he passed. At that time it had around 132K on it. The grandfather loved this car and it shows. Included with the car was a complete history of all repairs done since the original factory warranty expired. He had all work performed at Sarrant Cadillac in Farmingdale, NY which is the same dealer he purchased the car from. When I bought it, it had been sitting in the garage for over a year. I had to change the battery and alternator right there in his driveway as the battery was completely shot and the alternator couldn’t keep the car running. With that we were on our way home. First stop was gas where I used a top tier gasoline retailer and used premium unleaded. You could feel the flat spots on the tires but within a few days of driving was gone which is good because the tires have tons of tread and are fairly new. Anyway, on the way home that night I got the dreaded digital read out “Stop Engine, Low Oil Pressure. I immediately pulled into another gas station and checked the oil which was at the correct level. It appeared to only come on when stopped at idle speed (not instantly but after a few seconds after being at idle speed). Any application caused the warning to immediately stop. The car runs smooth and there were no engine noises so I drove the remaining approx. 40 miles home without any problems except the low oil pressure message when stopped at a light etc. I had the oil changed right away and had them use full synthetic which I’m planning on going back to conventional oil. My gut was telling me that it’s the oil pressure sensor. I began driving the car quite regularly and after a few weeks the warning stopped coming on without further corrective steps to correct the problem. I wrote it off as just having sat so long it needed to be well run in and then all was fine. Then I had the car pretty much just sitting for over a month as I took my time first using rubbing compound then polishing compound and finally a hand wax. Once done I began using the car again but our old friend came back, the low oil pressure warning message. So I’m wondering if having had been sitting so long before I bought it then when I had it sitting doing the cosmetic stuff it came back, if it has something with sitting for extended periods. Anyway I decided to go with my original gut feeling and bought an oil pressure sensor to put in as it’s amazingly easy to access. I’m wondering if anyone knows the proper torque spec for when tightening down the sensor. Thanks for taking the time to read through all my ramblings, I like to provide as much info and back information as possible to help come up with the correct answers. Incidentally the sensor I purchased is a Duralast part number PS267 with the pre-coated threads. It comes with a lifetime warranty. It was not the cheapest one they had so I’m hoping it’s better than the real “cheapoes”. Here is a picture of it:

 

3CCBB141-42B5-49DD-AF0A-6A8595727731.jpeg

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@Pelinaca1

First off, I had a 91 4.9, the alternator will NOT keep the engine running, if the battery is bad, I was in Bay Terrace, Queens and had a battery go bad and as soon as I hit the gas, the engine would stall as the alternator alone does not have the current capacity to drive the coils.   So changing the alternator was unnecessary.  In addition, never try to charge a dead battery with an alternator, charge the battery outside the car.  Jumping a dead battery and expecting the alternator to charge it whilst running the engine will overheat and damage the alternator quickly.   

By the way, I am on Long Island and have been to Sarant Cadillac on Hempstead Turnpike many times.  

Do not use synthetic oil in this engine, I didn't like the results in my 4.9, in a high speed run from LI to Virginia beach, the synthetic oil was consumed and I was 3 quarts low by the time I got to Philadelphia, in summer heat, when I pulled off into a rest area all my lifters were making a racket and I was 3 quarts low.  No problems for the life of the car after that using 10W30 mineral oil. 

Stop all the guessing and change the oil pressure sender, as you see it is very easy to change on this engine as the oil filter adapter is high on the engine.  Use a good grade of 10W30 and see what you get.  If the light comes back, I would tap and oil pressure gauge into the oil pressure sender location and see what pressures you are getting.  Don't worry about the torque, just snug it up and check for leaks after it is installed.   If you have synthetic oil in her, it could be your low oil pressure problem, synthetic flows 7 times better than mineral oil and that engine was not spec'd for synthetic and it has quite a bit of miles on it, I would get it out asap.

Also, make sure you are using an AC DELCO oil filter

 

Pre-1995 - DTC codes OBD1  >>

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