: Oil Pressure Drop on V8 NS



qpedd
07-14-05, 05:07 PM
I have an Oldsmobile Aurora 2001 (V8 Ė 4.0 North-Star Engine) - The oil pressure drops bellow 5 PSI at red light after driving it for over 20 minutes. This is specially true during hot days. When it is cold, PSI range is 16-60 and when it is hot 3-50. The manual calls for 5-30 oil. I have tried 10-30 and still have the problem. Should I go to 40 or I might damage something? Does oil have anything to do with this? Any insight that can point me to the right direction would be greatly appreciated specially direct emails.

p.s. I have read a few other posts in this regards but their engine were different.



Have a wonderful day

mcowden
07-14-05, 10:31 PM
I don't know that much about Auroras, so maybe I'm off base here. Where do you see that it's 5 PSI? Is there a gauge or a digital readout?

Maybe the oil filter is restrictive. What brand are you using? I would stick with the oil that's recommended in your manual. For a 4.6 Northstar it's 10W-30 for most of them. I don't know what the 4.0's require. I doubt the oil viscosity is the issue. If the oil pressure warning light isn't coming on, maybe it's not worth worrying about at all.

BeelzeBob
07-15-05, 01:07 AM
Aurora 4.0 engines were equipped with an oil pressure sending unit so oil pressure was available in the DIC information.

The question is....does the red light come on indicating low oil pressure or are you just expecting it to be higher???

The oil pressure sounds fine, actually. The engine is not supposed to make much oil pressure when hot and idling. The pump is a very high volume pump driven off the crank so as the RPM comes up the pressure comes up commensurate with what is required by the bearings. It is kept deliberately low to limit oil pump load and fuel economy loss.

If the low oil pressure light is coming on I would suggest replacing the low oil pressure warning switch with a new OEM switch as the original may be failing. Even the oil pressure sending unit may need to be replaced as those items are somewhat expendable with higher mileage on most any car due to the wear of the variable resistor wiper inside the sending unit particularily down at the lower ranges of the pressure curve where the sender spends most of it's time.

5W30 oil is the correct oil for the engine. Use conventional 5W30 for the oil and pressure the engine was designed with ... not synthetic.

qpedd
07-15-05, 11:13 AM
Thanks Boby, DIC gives me Low pressure warning(on display and with alarm sound) when it drops under 5 PSI (I have not noticed a red light) and if I donít rev it up, engine shots off. I donít want to do it with my foot on the brake and going to neutral at every stop in a backup can get quite annoying. The problem is more evident when I come off the highway to a stop. Sometime after driving slow for a while and after a few lights, it manages to stay above 5 PSI.

Any thing Iíll have to watch for when I replace these units? Do you recommend changing one first and then the other or go for both?

I used synthetic oil for a while. Last time I used conventional.

Michael, I use FARM filter. Thanks.

mcowden
07-15-05, 12:21 PM
Thanks Boby, DIC gives me Low pressure warning(on display and with alarm sound) when it drops under 5 PSI (I have not noticed a red light) and if I donít rev it up, engine shots off. I donít want to do it with my foot on the brake and going to neutral at every stop in a backup can get quite annoying. The problem is more evident when I come off the highway to a stop. Sometime after driving slow for a while and after a few lights, it manages to stay above 5 PSI.

Any thing Iíll have to watch for when I replace these units? Do you recommend changing one first and then the other or go for both?

I used synthetic oil for a while. Last time I used conventional.

Michael, I use FARM filter. Thanks.

qpedd, Bbobynski is the one to listen to around these parts. As far as using the Fram filter, I have heard and read stuff that scared me away from using Fram filters. You might find this web site interesting, but please don't take it as gospel:

http://minimopar.knizefamily.net/oilfilters.html

I think you'll at least avoid Fram filters in the future. Whether or not it will help your problem I have no idea. This is just FYI. I have personally used the PureONE, AC-Delco, Mobil1, Amsoil, and Wix filters with good success, but then again, I never had any failures with Fram filters either. Happy reading!

erroneous
07-27-05, 11:38 AM
If you dont mind me asking how did you remedy this??? I have the SAME problem in my 4.6 N* that you had/are having. Very frustrating, I have a thread going "stop engine low oil pressure" and I will try anything