Oil Pressure Sender?

Gary S.

Member
Joined
Jun 4, 2019
RO Number
34110
Messages
6
Hi again guys and gals.......
Coming in yesterday....My Oil Pressure Buzzer started sounding......Quick look at gauges.... 60 lbs. at 2000 rpm's......dropped it to 1100 rpm's.... STILL 60 lbs......kept a CLOSE eye on it....pulling up to the dock at about 600 rpm's....dropped to 55lbs. Warning Buzzer DID get quieter but never TOTALLY stopped.
Any ideas?
I'm gonna run down to Harbor Freight this afternoon and buy a Test Gauge just to verify everything. Any chance the sending unit went bad internally? I'm gonna stop at NAPA and pick up a new sender also.....for the price...it can't hurt.
 
buzzer will alarm for high engine temp, no oil pressure, or low/no drive oil
 
...and if the alarm circuit wires get loose or chafe to ground .
But the alarm circuits and gauge/sender circuits are independent of each other so you ...may... have a bad pressure relief valve ?

Did you check the engine visually back at the dock?
 
Transmission overheat will sound the alarm also. Seems even "professional mechanics" aren't always aware of this. My brother was on a test run with the mechanic on board, alarm kept sounding. Mechanic said engine temps and oil pressure were fine so he disconnected the alarm and had him continue on. By the time they got back to the dock, the transmission was slipping and too hot to touch. Transmission being replaced this week.
 
What year, what engine? 60 PSI sounds high. Like everybody's saying, locate the actual cause of the alarm.
On GMC engines, the oil pressure is taken at the back of the block and just before the oil filter. These are the only two access points directly after the oil pump. On the older GM engines that I work on, the idle oil pressure can be as low as 10 PSI and get as high as 20 PSI. I have a high pressure relief spring that allows the oil pressure to get as high as 45 PSI. I have a 1970 SBC (small block chevy) but all the early GMC engines are interchangable from 1955 to----. Bruce will get the dates right for me.
 
I think he said in another post that they were 1989 Crusader 502s. The oil pressure on my 454s never gets above 40 at cruise.
 
Could be a bad sensor. We had that happen on both our engines (diesel though).
 
I noticed I didn't put in the reason for my post. You can add an oil sender at both oil pressure access points and makes it easy to swap the wire from one to the other....if it even matters now.
 
don't you love it when a question gets many answers and the original poster can't be bothered to come back and acknowledge them and give an update?
 
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