: 96 Deville Northstar, No Oil Pressure out of the blue.

09-08-05, 10:35 PM
This car has been a nightmare, a customer towed the car to me and a used engine to swap out was a nightmare from the beginning, motor was completely seized so i had to slide it out of the transmission, anyways after everythings all done the motor ran awesome , except the coolant tube that runs on the back of the motor had a pinhole in it, which in itself is a nightmare to repair, then after the car ran for 30 minutes with no problems, it just lost all oil pressure and started ticking real loud.. i even primed the filter with oil before i put it on the car and cranked the motor over a rediculous ammount before connecting the coil packs. Is there something known on this engine ? Its a 95 Motor in a 96 Deville, swapped the intake over and changed the wiring to the knock sensor, but i know that would not cause this lol
Please shed some light on this nightmare .

09-08-05, 11:17 PM
Have you checked with a mechanical gauge to confirm? Those oil pressure switches frequently bite the dust...

Also, did you connect the oil cooler lines to the front of the oil filter housing? You CANNOT plug them with NPT fittings, oil MUST flow through there, so you have to either loop it around or install an oil cooler.

btw- if you did the above ^^^ and ran it for 30 minutes, it's trashed.

Here are the ports I'm talking about:

09-09-05, 03:38 AM
the engine will run without the oil switch. my 94 sls just had a bad ground cable in the back that cause it to go off for some weird reason. so you might want to check those. I believe mine was in the rear of the engine on the passengers side. I think you might have to drop the back of the engine down though to get to that.. But then again , that might not be your problem.

09-09-05, 02:39 PM
Eldorado: Unfortuneatly i did check it with a guage and it has 0 pressure..

It ran fine for 45 minutes had oil pressure it was fine, then all of a sudden it said shut engine off, now its shot...

I changed the 96 oil filter adapter over to the 95 engine so there was no oil cooler in the car.


09-09-05, 03:08 PM
I changed the 96 oil filter adapter over to the 95 engine so there was no oil cooler in the car.

And? On mine there's a piece of U shaped tubing between the two ports. This is the "oil cooler delete" option, if you will. If there's nothing connecting the two ports, the engine will starve for oil...

Another option, some people have noticed no oil pressure when the harmonic balancer bolt comes undone a bit. Something about the oil pump requiring it to be torqued down adequately to function. Might want to check the torque on that.

09-09-05, 05:43 PM
The oil pump is driven by clamp pressure from the harmonic balancer and bolt.

09-09-05, 05:44 PM
We had a problem with those sticking the check valve in the oil pump with trashyou might add about ten qaurts of oil to it and run it for a little while then drain it to the proper oil level and see if that cleans it out.there was a bulletin on this at one time.

09-09-05, 06:30 PM
I recall that being mentioned before. Putting about 18 qts. in the sump, submerges the pump in the event it lost it's prime and will reprime it and possibly flush the debris out of the check valve.

09-12-05, 07:37 AM
I just tried putting the oil in ill let it sit for a while and see what happens..

As i said, i took the oil filter adapter off the old engine, the one that ran so must have been okay before.

I cant believe this would happen, this motor ran with no noises and plenty of oil pressure for almost a full hour then bam no oil pressure...


09-15-05, 12:55 PM
filling the motor with oil fixed the oil pressure problem i ran it for like 5 minutes with 18 quarts of oil, it had plenty of oil pressure and motor was ticking very slightly.. Drained it out filled back up to proper level, ran sweet plenty of oil pressure for 1 hour, shut car off started back up no oil pressure


Looks like ill have to put another motor in, Good thing its not my motor!

09-15-05, 05:33 PM
Sounds like the oil pump check valve rather than the motor.