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3K views 15 replies 10 participants last post by  Cadillacboy 
#1 ·
I recently bought a '97 with 80,000 miles. When hot, the "Stop Engine Low Oil Pressure" message comes on at idle and there is a bit of lifter noise. I don't know what oil it has in there right now, but I would like to try some 20W-50. Any possible problems? I don't expect to start it at temperatures below 50F.
 
#5 ·
In answer to your question, Do not, at any time, for any reason, run 20W-50 in a N*. The production tolerances in the engine are not "open" enough to allow heavy duty diesel oil use.

Weights other than 5W-30 and 10W-30 are NOT recommended by GM, or practically every other passenger vehicle manufacturer. Read your owner's manual or download one from this site.

First, I would change the oil and filter, using a top grade 10W-30 and either an ACDelco or WIX filter. Do a couple of WOT runs as explained in many places in these performance threads. Do a ^^^ search. That will probably cure or lessen the idle tick. IF the low pressure at idle warning comes on again, change the oil pressure sending switch which is on the front of the oil filter adaptor. Again, there are several threads concerning this, usually clustered in the summer months.
 
#9 ·
You have a mechanical problem. Trying to cover it up with a bandaid is going to make things worse.

The N* doesn't need much oil pressure at idle, but if you're triggering the warning light, you've got a problem. I would definitely try to find out if the previous owner did any work on it.

If not, it sounds like you have an internal oil manifold leak. Underneath the oil pan is a pressurized oil manifold that distributes oil to the various parts of the engine. It is sealed with silicone beads. If some of those silicone seals are damaged, pressurized oil can leak out back into the oil pan. Kind of like "internal bleeding" I guess. I think repair involves engine removal ($$$$)
 
#14 ·
The oil pressure sensor on a Northstar has a unique calibration. Replacing the sensor with an aftermarket unit is likely to result in false indications of low oil pressure. The first step in the systematic troubleshooting of an oil pressure problem is the installation of a calibrated gauge to determine if it is a pressure problem or an indication problem. The object of the exercise is not to make the light go out but to determine what is really happening and verify adequate pressure.
 
#15 ·
let us know something. in every car i had we've ran castrol 20w50 in they went 200,000 miles+ easily. i remember when i was younger my mother had a chevette that had like 300,000 miles+ plus before it died(was the happiest day of my life when it did die). also, my 88 deville 4.5 liter has castrol 20w50 in it, and it has around 197,000 miles on it with the original motor and transmission. please give feedback how the northstar responded, like it was stated above i want to know how you turned out.
 
#16 ·
20W50 ? Well, we used to use it in our beloved XJ40 .Let me tell you a story of it .When Castrol first introduced their newest oil technology Magnatec, I thought that was the best way to protect the engine in long run despite the handbook underlined 20W50 and compatible for the engine .Then ,we filled up the car with 10W40 Magnatec.A few months later, I visited my Jag Specialist and I told them if it was good for the car ...Guess what ????
He strictly disagreed and told that it was gonna damage engine components namely crank if we used it .Then ,drain the oil and refilled 20W50 back .He told us it was the best way to keep what your handbook says when it comes to the oil . So,it's not like tranny oil .I mean Dex VI is the best and can be used in your pre DEX VI filled car but not same thing runs for the engine
In a nutshell, use what your handbook says in a Northstar . I have been hearing some owners can use 10W40 ,0W40 etc but I don't think that's a good way to go
 
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