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5.3 L, oil pressure sensor

1334 Views 6 Replies 3 Participants Last post by  apcnc
Initially after starting engine, the oil pressure gauge stays at 40psi or just under. Even once engine has reached operating temperature the gauge doesn't move until after driving for at least 5 minutes. Then the gauge starts reading correctly(going up to 60-70psi and down to 30-35 psi) depending on engine RPM. Initially it doesn't mater the RPM, it stays at 40psi.

The engine has 193K on it and I noticed this behavior around 190K. Is the pressure sensor on the motor itself failing or partially failing? Where is it located on the engine?

I don't believe this is normal behavior as I have been watching the gauge in my 2002 S10 and it goes 60psi+ everytime I start it, no matter if the engine is cold or warm. I understand the sensors are most likely different as the S10 is a 4Cyl and my Silverado is the 5.3L V8.

The behavior is annoying to say the least. The oil is not low either, even though I have a slight rear main leak and/or oil pan gasket leak. I switched to a synthetic blend oil for higher mileage and I am 99% certain that has made the oil pan gasket issue. It was never a synthetic oil motor, so I caused that issue. I didn't catch the synthetic blend detail on the bottle until after I had ran it about 1000 miles so that is my bad and I will deal with the leak. The gauge issue started before I made the oil switch though.
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Blockage, bad bypass? How bad was the oil? How often is it changed?
left rear top of the block.
Oil was fine, changed every 3-4k. I was taking it to the dealer, just don't have the time to wait around for it anymore. It's cheaper usually, but the time cost is more.

Not sure what you mean by blockage or bad bypass? Are you saying the sensor is partly blocked?
Sensor could be blocked or leaking. The bypass in the oil pump. Bypass in the filter also. Could be a bad filter or stopped up.
Unplug the sending unit and see if it has oil in the connector.
silverado2k said:
Initially after starting engine, the oil pressure gauge stays at 40psi or just under. Even once engine has reached operating temperature the gauge doesn't move until after driving for at least 5 minutes. Then the gauge starts reading correctly(going up to 60-70psi and down to 30-35 psi) depending on engine RPM. Initially it doesn't mater the RPM, it stays at 40psi.....The behavior is annoying to say the least.....
Not sure I understand why this would be annoying. Is there anything about the vehicle engine that is not operating normally? Recall that most vehicles don't even have an oil pressure gauge....most likely for this reason....folks try to read too much into what the gauge indicates.
GR2017 said:
Not sure I understand why this would be annoying. Is there anything about the vehicle engine that is not operating normally? Recall that most vehicles don't even have an oil pressure gauge....most likely for this reason....folks try to read too much into what the gauge indicates.
Not paying attention to an oil pressure gauge can also bite your in the ---. If you only had an ID-10-T light its to late and you must shut down or damage the engine. Whereas many times you see the problem coming with a gauge.
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