View Full Version : oil pressure light 4.9 liter

05-18-12, 10:33 AM
My 93 deville has been started every blue moon for the past four year while in a paint shop. Recently I have got the car back and changed the wires platinum plugs, battery, alternator, starter, pull down trunk motor, struts all around and oil with synthetic. After all that money spent plus 5700 in paint and body work the oil light stays in when the car is off. I was told my motor is locking up. Please guys help me on this one!

05-18-12, 11:06 AM
Motor locking up because the light stays on WHEN THE MOTOR IS OFF? Ridiculous! Sounds more like an electrical problem.

05-18-12, 11:43 AM
Well the mechanic went behind the passenger wheel and tried to turn one if the pulleys on the motor and said there is too much tension. Although I had him to come over to find the electrical problem because the car dies out after about ten minutes running. Could it just be the electrical problem is it?

05-18-12, 02:31 PM
Too much tension? He's turning the crankshaft by hand and thus trying to compress the air in the cylinders by hand (unless he had all 8 plugs removed). If the engine was "locking up" I doubt it would be running now. Might want to look for another "mechanic". My money is on a failed oil pressure switch or maybe a short or open in the circuit somewhere. Remember, the oil pressure light alerts you when the oil pressure is low. There is no oil pressure when the engine is off and should be no current to the switch when the ignition is off. Now key (ignition) ON, engine OFF (aka KOEO) is another story. In that configuration you have current to the switch, but no oil pressure so the light should be on.

05-18-12, 06:03 PM
Does the oil light go out when you take the key out? I think one of my cars did that when the horn relay blew. just my .02

05-18-12, 08:33 PM
Buy a cheap mechanical oil pressure gauge from harbor freight and put the adapter in place of the oil pressure switch. Run engine and observe. 35psi+ at 2000 rpm = :thumbsup:

05-19-12, 10:54 AM
I know this is a dumb question but you never know. Does it have oil in it? Check the dipstick? :suspense:

05-19-12, 06:26 PM
Thanks a lot cadi lovers. Oil pressure switch has been replace and the light has gone off. Love you people!

05-19-12, 06:40 PM
Well that was easy!