Jump to content
CaddyInfo Cadillac Forum

Low OIL press only @ Idle


Recommended Posts

Ok my buddy has a 1996 Deville with low oil pressure @ idle causing the the light and the message to come on. He has changed the oil press switch and flushed the car with new oil many times, still low oil press @ idle.

He was about to order a new oil pump when I remembered seeing on here many times that the oil pumps themselves in the N*Star hardly ever go out.

So what else other than the balancer torque, etc can we check before we tear into this thing??

Like I said before, only low press @ idle, once engine is above idle everything is good.

:unsure: Car only has 70K on it.

Link to comment
Share on other sites

i mentioned this before on the other thread but maybe it got lost in the clutter. in some cases, the brand of oil filter can cause this condition. i have never heard of it happening with the n/s but who knows? is he using an oem filter?


90 seville 100k

Link to comment
Share on other sites

Use a good grade of 10W30 and synthetic is not recommended. Its possible that he has diluted the oil with gas due to a bad injector. Change the oil and see what happens...

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

Link to comment
Share on other sites

Was an OEM pressure switch installed or was it an aftermarket switch? Also, have you temporarly plumbed in an oil pressure gage to check the oil pressure at idle?

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

Link to comment
Share on other sites

Second the notion that the brand of the switch can and does matter. If it were a cheaper GP Sorenson brand switch or similar, it's hard to tell how accurate that'll be. The spec oil pressure at hot idle is 5 psi...not much. Any SMALL variability in the tolerance of an already cheap switch can provide erroneous readings. We've seen before where an ACDelco switch cured the "low oil pressure" condition. Good luck!

Jason(2001 STS, White Diamond)

"When you turn your car on...does it return the favor?"

Link to comment
Share on other sites


I agree with KHE - add in a pressure gauge and see what's going on at idle.

With respect to the filter causing a problem, I recall a bypass valve on the oil system that will go around the filter if the path restricted.

One very remote problem may be the oil pump pressure relief valve that is inside the oil pump housing. If this sticks or has debris in the seat, the pressure will drop. Would be a curious problem with only 70K on the engine unless the car has been poorly maintained.

I suspect a problem with the new pressure switch or the oil viscosity.

Let us know what you find. Hopefully you won't have to dig into the engine.

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...