Oil light in dash Question
 

1964 GP 389 4 bbl ….dash oil light comes on….and dip stick says Full. Can these sending units act up ? Thanks

Yes it could be bad sender or no oil pressure. Check it with a known good gauge

When does the oil light come on, at hot idle and then go off at around 2000 rpm?

The oil light measures oil pressure not the oil level. In short the sending unit can go bad and the light can come on especially during hot idle. It could also be low oil pressure due to a worn pump or worn bearings. The only sure way to know is to temporarily plumb in a gauge and check the pressure.

X2 with post 5!

Also if with the motor cold and you crank the motor and the light goes off once the motor starts up then there’s a very high percentage that the sender is still good when the motor is fully up to temp, as in 5 minutes of driving around in temps above 60.

So I started up the GP….and the light came on after 25 seconds of idle time. Then i let it warmed up at idle ,in park, for 5 minutes. The light stayed on …BUT WHEN I JABBED THE GAS PEDAL….the light went out for a second ,then came back on. I change the oil and filter every spring…but havent changed it yet. Had this car for 5 years and this is the first time this light has come on. Maybe an oil and filter change will do the trick. Probcably 1000 miles driven last year

If you hold the throttle at 1000-1500 does the light go out ?

It sounds like to like the oil pump check ball is being kept unseated by some crap from the bottom of the pan, non the less I would not run the motor any longer until I had a cheap mechanical gauge hooked up to the where the sender currently is to confirm what may or may not be going on with the pressure.

Ok …thanks for the info

The sender is set to turn the light on if pressure drops below about 4.5 pounds. If the light is on and the sender is good, the actual pressure is below that amount but you just won't know how low it is until you get a gauge plumbed in.

Could oil over fill …cause this problem. .?

100% no on that!

Thank You....got a guage coming...

Attachment 591806

We have oil pressure at a hot idle ..YIPPIE !!!!! So the sending unit was bad. I all my years …this is the first sending unit that gone bad…lol And many thanks for those of you that gave me the info on that guage . Thank You

Yup , your golden!

Great! :drive:
Money well spent for that tool.

For sure !…and when I ordered the guage….it was here THE NEXT DAY !